everyone if you want to make your way in and take a seat and we will get started. Welcome back to week eight of the semester everybody.

Before we get started on today's content we're going to have a check-in again. So the aim of today's class is we're going to be talking about the development of executive functions.

What executive functions are, how we might measure them and why we want to understand how executive functions do or do not change across development.

not change across development. First, as I say, let's have a check-in. How are we all feeling today or this week?

all feeling today or this week? I was listening to some rants going on in various corners of electrical, so I think there's a spreader feel.

Whoever's feeling number 16, I think I'm with you today on that one, so.

Okay, we've got a good variety again of different feelings going on. I feel like we are over the mid-way point of this semester but there's still quite a way to go so you can understand some of those feelings going on if everyone is doing okay.

those feelings going on if everyone is doing okay. Before I start talking about executive functions I just wanted to get an idea of what kind of things you already know. I know some of you will have come across them before in level one level two but also you may have general thoughts about them so what comes to mind when you think of executive functions terminology wise usefulness often wise, when do we use them, what kind of words?

what kind of words? I believe there's more than one person that can think about executive functions.

Okay, good, a couple of good ones to kick us off. So planning, yeah, we might use our executive functions to plan things, problem solve, thinking about different potential options and how we can plan ahead to solve different problems, using them to make decisions, to pay attention to things, nice.

Any other higher order functions.

Nice. That's kind of a more academic way of viewing them, that they are these higher order functions. Brilliant. We'll come back to those.

Working memory. Nice one. Top down, attention, planning, goal-directed actions.

So making sure we're using things abstract thinking, that's a nice one as well. So looking at things not just as they are, but thinking of different counterfactuals, different options and things more abstractly. ADHD, really nice link there.

So yes, executive functions tend to be less well developed or less utilised in ADHD or that's what ADHD is typically associated with, goal directed actions, I've said some of these, sorry it's moving around, top down, decisions frontal lobe, excellent, okay, we have a good overview of those different things. All right, keep mentoring me to open until later and we will come back to do some quiz questions later on.

So as I say, we are in week eight now and we are going to be week eight of semester two and we're going to be focusing on the development of executive functions. We're going to talk about executive functions including working memory towards the end of today, although I'm not going to talk too much about memory because we're going into that in much more detail next week and then we'll be looking at medical admission in the final week. Today we're going to be learning about what the executive functions actually are, how would we define them and how can we conceptualize them. We're then going to focus on three specific executive functions, inhibitory control or inhibition, cognitive flexibility, which is also known as switching, and working memory or updating as it's sometimes referred to.

Finally, we're going to be looking at whether these are three of the same thing that just have different labels. We're using them in a different different context or are they actually separable things? So can I have cognitive flexibility without having inhibition and working memory or are all of them really intertwined and we're going to talk about what executive functions are, how they can be defined, and then we're going to zoom in on this idea of inhibitory control inhibition. Executive functions, many years ago, used to be referred to as possession of willpower, highlighting its role in directing our attention to behaviour to achieve different goals, as you all just said in that word cloud.

The term executive functions itself is an umbrella term, referring to a number of different subcomponents, as we're going to talk about throughout today. We can clarify the component or the title and the meaning behind executive function further by looking at some of the different meanings that might be withheld underneath it. So let's first have a look at this idea of executive and what this may mean. Executive is used across many different contexts and across different scenarios. For example, if we think of executive as being the chief executive officer of a company, is referring to someone who manages other people, who directs different actions and different goals to work towards a more common or bigger goal, or overall goal. Executive can also be used in a context of something, for example, like the executor of a will. And here the term is referring to someone who executes a plan, who puts a plan that they already have into action, again, helping to plan and achieve a specific goal. Each of these definitions of the term or the word executive helps us to understand that broad nature of executive functions in terms of their role, as again was mentioned in that word cloud, of being in charge of various lower-level processes that occur in behaviour, being the person that's issuing those directives and getting the overall smaller goals accomplished to achieve a larger higher-order goal.

More specifically then, we might define executive functions themselves in a multitude of different ways or a family of top-down mental processes needed when you need to concentrate and pay attention to something.

Other reaches have also used the term top-down referring to the neurocognitive processes that are specifically involved in goal-directed behaviour and Carlson defines executive functions as higher order self-regulatory cognitive processes that are helpful in the monitoring and control of both thoughts and actions.

So as we can see here and it's really important to note, Executive functions can be defined in subtly different, slightly different ways, but they're all tending to converge on similar themes of abilities that are designed to help you achieve higher order goals, directing of intentions and attention, and involving self-regulation of control, what you're focusing on at any given task point. They also tend to indicate the role of these top-down processes, which specifically means that these capacities are both intentional and voluntary, as opposed to being automatic or subconscious processes that we're doing.

So this is when we're actually thinking about something we want to achieve and we're using those abilities to do so. Executive functions are typically, although not completely exclusively, associated with the frontal lobes and particularly the prefrontal cortex. There are some other brain regions that are identified as being associated with executive functions, but these are the most dominant brain regions that are commonly associated with executive functions and the use of these executive function processes.

The prefrontal lobes and the prefrontal cortex.

Given this then, we should be able to make some pretty solid predictions about what would happen if we have damage to the prefrontal cortex.

If executive functions are associated with the frontal lobes, the individuals who experience damage to the frontal lobes, and that could be as a result of an accident, a stroke or some sort of brain injury, they should experience impaired executive functions as a result of this.

So we have to ask then is this actually the case? Is it a case of when you have damage to those areas of the brain we have these problems in executive function? Well as always in psychology and because I wouldn't really include this if it was a straightforward answer, nothing is ever as straightforward as we'd like it to be and the answer is that there's mixed evidence about whether damage to the prefrontal cortex has the effects that we would expect to see.

Now hopefully for some pretty obvious ethical reasons we cannot go around damaging people's frontal lobes just to see what the impact on their executive functions are. But what we can do is make use of case studies where this damage has already been acquired to look at what the impact is on that individual. One of the most famous cases of this kind of damage is that of Phineas Gage.

Phineas Gage was a construction worker working on a train line when he was 27 years old when he accidentally triggered an explosion and as part of that explosion he was involved in a work accident which sent a metal rod right through his brain particularly destroying much of his left frontal lobe and this image here illustrates where this pole went through and where his injury was acquired.

Now Gage is a particularly miraculous story because he survived this injury but with noticeable impairments afterwards.

In particular it was noticed that his personality and behavior were vastly different following this injury compared to before He was defined or described as being a lot more temperamental, very quick to anger, and he had less of a filter in terms of his speech, with it noted that post-injury he was very free with his cursing, which was unlike him before the injury. These changes in behaviour and personality could be attributed to changes in executive function abilities. For example, if you have less ability to inhibit yourself, that might be where you're a little bit more blunt with your friends, or you say things that you would usually kind of inhibit and not actually say in the context. I'm sure we've all had the odd moments where we've maybe had to bite our tongue and not say the thing that we really want to say. Without inhibiting control, we wouldn't be able to hold those thoughts back. Interestingly, though, despite his seemingly changes in his temperamental and personality outcomes, Phineas Gage still performed at average or normal levels in terms of other tests of intellectual abilities and general cognitive abilities, even measures that require some level of executive function, such as his memory.

So his memory didn't seem to be hugely impacted by the injury that he had acquired. So he didn't therefore have absolutely no executive function at all, and this suggests that other parts of his brain must have been involved, must be compensating in some way, although his overall executive function was greatly reduced. Now, one of the problems with case studies like this is we can't make big claims and develop full scientific theories, particularly about the role of executive functions, based on one particular person, so on one single case study.

We need more evidence. And in this published paper by Cater and colleagues, they also had a second case study with Patient CD.

Patient CD received a very similar injury to Phineas Gage with damage to their left frontal skull and following this injury patient CD reported behaviours were very similar to those of gauges wherein their intelligence was overall unaffected by the injury they had normal IQ scores and good broad cognitive function so they could go about their daily lives with some semblance of normality although it definitely changed from before the injury.

In contrast patient CD like Phineas Gage did suffer from dramatic problems in their social lives.

So this included their ability to form relationships, to manage their own behaviour, to hold a job and to control their impulses. So essentially, and as I say, it's a case study, so this is kind of people describing things, but they essentially described him as becoming a very unpleasant person to be around, they were unreliable and they were hard to work with, they would say things were inappropriate and made them uncomfortable to work with. In this paper, they present detailed case studies of both patient CD and Gage, and in their case study of patient CD.

Kater and colleagues found that following their injury, CD is still presented with average or even slightly above average IQ level and even showed relatively average performance on some tests of executive function.

So this seems to suggest that damage to the prefrontal lobe is not directly related to capacities such as intelligence or broad cognitive abilities. However, some of the symptoms experienced by both Phineas, Gage and patient CD do indicate some links with poor executive functioning.

For example, despite these relatively positive outcomes, patient CD was shown to have very poor levels of inhibitory control, greater levels of impulsivity than average, which is linked with this inhibitory control or changes in that, the inability to withhold a response or inaction, and well-documented difficulties in forming relationships. In particular, patient CD was found to have significant impairment in their ability to engage with a task which requires coordination of multiple abilities at once.

So this seems to be likely linked with this executive function of cognitive flexibility, being able to do two tasks at once or answering the phone while also taking something out the oven. Multiple things are happening at one time and you have to flip your attention between those. So patient CD was particularly affected when trying to coordinate multiple different actions.

Okay, so having talked about executive functions more globally, defining their purpose, so they're helping us to actually engage in everyday life to perform actions and things.

We're going to break down what executive functions actually are, so how they can be specifically defined.

There are a number of different abilities or capacities that have been argued to be an element of executive function.

For the purposes of today's class we're going to focus on three of these, so three core executive function abilities, that there is pretty much a general consensus about.

And by that I mean that there is a consensus that these three abilities do exist and are executive functions. So we're going to focus on inhibition, which is also known as inhibitory control, working memory, which is also known as updating and cognitive flexibility, which is also known as shifting.

We're not going to talk about planning, which has also been argued by some researchers to be a fourth executive function. And there are other researchers that think that planning is just a side effect of the combination of all of these three abilities, which is why left them out for today but you may come across them in some of the literature. Okay let's focus first on inhibitory control. Inhibition refers to our ability to resist distraction as well as to inhibit a pre-potent response such as habits or motor response that we've already started and we need to hold back so something we start doing and then we realize we need to actually change.

So it's the ability to stop ourselves from doing something, whether as a result of external or internal stimuli. Because I try and make some of these examples memorable, I'm going to tell you one of my most embarrassing moments that has ever happened in my life, but I won't talk about it again afterwards. But it's a really good example, I think, of inhibitory control. So this is pre-COVID, so it's a few years ago now, but I was at a Cayley. It was one of those dances where you get moved around lots of different people and I was about to stomp my foot down and as I looked down I realised that somebody had got so enthusiastically flung around that there were some false teeth on the floor and if I carried on with my foot they would be very crushed false teeth and I managed thankfully to stop my foot from going but that was me stopping a prepotent action. I was already in the middle of the, I wouldn't call myself dancing, but movement, my foot was stomping down and thankfully the teeth were not crushed. But this is an example in the real world of when you start an action something happens in the environment that means you need to change and bring the action back and we have wide individual differences in how well people can actually inhibit those responses once you've already started them.

I don't know who the teeth belonged to because I just left them on the dance floor so who knows what happened after that.

Anyway okay two of the most well-known measures of inhibitory control are the delay of ratification tasks, the marshmallow task, which we're going to come back to shortly, and the stroop task.

The stroop task involves presenting participants with words, colour words such as this, and they're either in matching congruent ink, so the word blue in blue ink, or incongruent ink, so the word blue in yellow ink. In this task, participants are asked to ignore the ink colour, ignore the word and focus on the So here the correct answer would be blue, yellow, red, purple, black, but here the correct answer would be yellow, red, blue, green and purple. When we are reading things, we want to just, we want to take the easiest route. And in this route task, there is this dependency or presumption that people want to just read the word that's presented to them. And so we have to inhibit, suppress that, that desire and instead focus on that ink colour. So this is measuring inhibitory control and the faster you present the stimuli, the more areas people tend to make.

I wanted to highlight these two tasks in particular to note that inhibition is not just one thing.

These tasks both measure inhibitory control but they seem to tap into very different things.

The marshmallow tasks has a particular thing, a marshmallow or a sweet whatever it may be, that has that immediate gratification for people if they choose to actually engage in inhibitory control.

The stroke task is more just a measure of the ability to do but there's no inherent reward for doing so.

And thus the motivation to inhibit in each of these tasks is very different.

The words interfere with each other, but there's no apparent intrinsic reward.

I'm going to use a generic term of inhibitory control across the rest of this class, but I just wanted to highlight that when we're talking about these things, they're not one thing. We can use this inhibitory control across many different domains and different contexts, and it may change how it's defined for individuals in that.

Okay, so let's have a look at some of the different ways we can measure inhibitory control, particularly in infancy and childhood. Inhibitory control can change with age and therefore different tasks need to be developed to allow accurate assessment of inhibition abilities across childhood.

This allows us to get a better insight into how inhibitory control first starts to develop and how it may continue to develop across childhood, adolescence and into adulthood. Working with children, if any of you have, across, or even if you've just heard about the course of semester, can have lots of challenges and it requires appropriate tasks to be developed to make sure they are suitable for the age group you're looking at to check that you're actually getting valid insights into different cognitive abilities of interest.

There are a number of tasks that have been developed to tackle questions of inhibitory control development in childhood and we're going to focus just on three of them. We're going to look at the freeze frame task, which was used developed to measure inhibitory control in infancy, a delay of gratification task, which is for preschoolers, slightly older children, and then a stop signal task, which has been developed to be used with older children about eight or nine through two early teenagers. Okay, let's focus first then on measuring inhibition during infancy. I'm going to talk about particular paradigm developed by Carla Hombot and colleagues, who wanted to measure or wanted to establish when does inhibitory control first emerge in infancy.

We know that by their first birthday infants do have some level of inhibition or inhibitory control, meaning these capacities must develop throughout the first year of life, we just don't know when it is that they first start to emerge.

Newborn babies tend to be quite reflexive rather than purposeful in their actions, meaning they may not be proactively engaging in inhibitory control and therefore it must emerge a little bit later on. Holmgurman-Curry has conducted a longitudinal study to try and establish when we can first see inhibitory control during infancy.

And for this study infants completed a number of different measures including the A0B task which we've talked about a few times and a couple of weeks ago in the first lecture of this series and in particular we mentioned about the fact that the A0B task has a a pure measure of inhibitory control that may also require working memory abilities. So if an infant fails the A, not B task, it's not clear whether it's due to their inhibitory control not being developed enough yet, or whether it's their working memory that is failing them, or both. The second task that they used in this study was the freeze frame task which they developed in order to measure inhibitory control in infancy. One of the key strengths of this study, or of this task I should say, is that it is argued to assess inhibitory control itself. So they're trying to have a pure or as pure as possible measure of inhibitory control independent of working memory. So that is to say the task itself removes any need for working memory to perform well but retains the need for use of inhibition.

In this freeze-frame task, infants are presented with an interesting moving stimulus in the centre of the screen and then they see four distractor objects appear around the side of the screen.

If the infant looks towards the boring distractor objects around the side of the screen, then the one in the middle stops dancing and disappears.

And so if the infant wants to keep the interesting stimulus up on the screen, they need to use their inhibitory control to avoid looking at the distractor objects, excuse me.

me. So that looks something like this. You've got the dancing star in the middle of the screen, we then have four boring squares appear around the center, around the outline of the square screen. If the infants want to keep that star dancing and moving, they need to keep looking at it. The minute they look over to one of these squares, the star in the middle disappears. And so this star is meant to be a rewarding thing that they want to look at, and therefore they need to use their inhibitory control to focus their attention on that specific thing. So this task, along with the A not B task, was presented to infants age six and nine months old, and they wanted to see whether performance on each task was correlated. So if they did one, would they do the other and whether there was any differences between performance on these two tasks. So what did they find?

So what did they find? Well, results show the infants were able to use inhibition.

Well, infants they're a level of inhibition at six months old. So their ability to keep their attention focused on the moving star in the freeze frame task predicted the infant's ability and performance on both the freeze-frame task and the A0B task at nine months old. In contrast, there was no relationship between performance on the two tasks at six months old. So at six months old, even if they could do the freeze-frame task, it didn't necessarily mean that they were passing the A0B task, but their performance on the freeze-frame task at six months old did predict how well they would do on both tasks at nine months old.

There was no relationship between performance on the two tasks at six months old suggesting that the A0B task and the freeze-frame task are requiring or tapping into two different types of inhibitory control.

Or as we mentioned a second ago it could be that the A0B task performance could be explained by working memory development as opposed to inhibitory control.

So maybe they're not remembering the location of the object when it's been hidden, the working memory isn't developed and therefore they can't pass the A0B task yet.

By the age of nine months, however, infant's performance on these two tasks was found to be related.

So similar performance at nine months old, such as if they pass the freeze frame task that also pass an A not B task and vice versa, suggests that they do have both of these abilities by the time they're nine months old.

And so the researchers argue that these results indicate that some form of inhibitory control is emerging and developing by the age of six months old, indicating that from this age onwards, infants are better equipped to use their inhibitory control across a number of different contexts.

Now, again, if we're being critical scientists, a note of caution, this is a really interesting paper and it suggests that some level of something is developing around six months old, the fact that infants can maintain their attention on that star in the freeze frame task. However, we do need to keep in mind that there are limitations to these designs.

For example, here they've interpreted results from looking times. Looking times provide us with an indication that something is happening, something different is being processed across these different contexts, but it doesn't tell us what the infant is thinking or what their strategy is, if there is indeed a strategy. So although we can make some assumptions and assertions about these looking times, we have to be cautious in how much we actually attribute to the infant in terms of their inhibitory control. So maybe something else can explain the results as well, but this gives us an indicator that some form of inhibitory control is present at these ages. Okay, so let's move on to the assessment of inhibition in preschool age children, a little older than the previous study. The most infamous test of inhibition in this age group is, as I mentioned earlier, a degree of gratification tasks such as the marshmallow task. In the classic version of the marshmallow task, a child is given a single marshmallow before the experimenter says, I need to leave the room for a minute. They leave the room. The child is told that if they can wait until the researcher returns, they will get a second marshmallow, so they get more sweets that way. Whereas if they eat it while the research is gone, they will not get that extra reward.

So this means the child has a choice. They can either eat a single marshmallow in front of them or they have to engage and delay their gratification and wait so that they get more sweets at a later time point. So let's have a look at some of the responses to the marshmallow task.

The marshmallow test is a really great way to show how children delay gratification.

We tried it out with the four children we've been following since September 2010, Alfie, Millie, Mackay and Pratma. Here's how it works.

We have each child on their own sit at the table at a desk with a plate and one marshmallow. They could either choose to eat the marshmallow, the one marshmallow, right been in there or they could wait until I came back into the room and have two marshmallows. I left them alone in the room for 15 minutes.

Take a look. The marshmallow test has been used for decades by psychologists.

It's been used with children to predict later academic success including literacy, SAT scores and other academic outcomes.

There's no definitive answers from the marshmallow test. It's not a matter of passing or failing.

What we're looking for is whether children can really resist this piece of white candy sitting in front of them that's sweet, that you know the smell of it, the lure of the marshmallow. In Pratmesh's case, we really saw this added curiosity because he'd never actually tasted a marshmallow before. All of the children managed to show some level of self-control and resist the temptation to eat the whole marshmallow. As you can see from the footage, you can catch a glimpse into children's ability to control their impulses.

This ability which is developed around the time of kindergarten can be linked to other outcomes later in life. At the end the marshmallows were in kind of different states. Some had been squished ripped apart and nibbled around.

There was this temptation and there was this impulse to kind of try it out.

So we can see there a variety of different approaches to the task And as was mentioned in that video, performance on this marshmallow task at around four years old or three or four years old is argued to predict later performance in academic settings and in IQ tests, etc., which I think we'll come back to in a little bit. Okay, so results across a number of studies have shown that if left alone with nothing to do but stare at the marshmallow, four-year-old children often last less than a minute when left alone with that marshmallow before they decide to eat it.

However, if you give the children a distractor or they're prompted on how to distract themselves in this, they can actually last between eight to 15 minutes, successfully not giving in and not eating the marshmallows. If you say to them, think of something fun, distract yourself, play with this toy instead of the marshmallow before I come back, before the researcher returns, then they do much better at delaying the gratification of that marshmallow task. Further researchers wanted to find out what factors may actually influence a child's performance on the marshmallow task. Is it just what you do in that marshmallow task is what you do or can we influence how we perform in that? So to test this they had children between the ages of three to five years old take part and a key manipulation in a study was before completing the marshmallow test children were implicitly manipulated to believe that the research the model in the task was that they were interacting with was either reliable or unreliable.

So, to achieve this, there were two prior tasks the child had to do before they were doing the marshmallow task. One involved colouring in and one involved stickers.

When the task first started, or the experiment first started, the children were presented with a colouring book and some crayons and stickers. The crayons were really worn out, so really run down as small. The stickers were mostly used, there were only a couple left on the page. The researcher would then say something like, oh, I think I have some new crayons or some new stickers, let me go and them and then it would leave the room for two and a half minutes. After this time had passed, the researcher would return to the room and children were randomly assigned to one of two conditions.

In the unreliable condition, the researcher who had said they were going to go and get some new pencils or crayons and stickers came back and said, oops, I couldn't actually find any, I don't have them, sorry about that, you'll have to use the ones that have already been used.

And in the reliable condition, the model, the researcher did return with new crayons and new stickers.

And the aim of this study was to see whether this manipulation of this reliable or unreliable researcher would affect the performance on the marshmallow task when the children were left alone. So after they completed this they completed the task of the colouring in and these stickers and then they were set up as we just saw in that video the marshmallow task left with a plate with just one marshmallow on it and what the researchers wanted to see was would the unreliable versus reliable condition drive different performance? And to get straight to the point, yes, that is exactly what they found. So results showed that when children were in the unreliable condition, when they couldn't trust the research was going to come back with that second marshmallow, which is this black data here, they found that the children could last, I think that's about three and a half minutes before they would actually eat the marshmallow, whereas the children where they'd been shown that the research was reliable before could last almost 15 minutes, so we're much more able to delay that gratification. So what these results highlight is that previously established poor performance of young children on this delay of gratification type task is actually very flexible.

If a model or a researcher has previously failed to follow through on a promise, children are less likely to dedicate the resources to delaying that gratification, instead going ahead and eating the marshmallow. However, if they know that the research is trustworthy and has been reliable previously, they're able to engage in that delay of gratification for much longer amounts of time. And this further highlights something very important about executive function abilities, which is that they are very flexible and can be affected by context.

So your inhibitory control could be really good in some contexts, but in other contexts really struggle with it. Okay, so given these results, then, it seems that standard delay of gratification tasks may have some problems.

Specifically, classic tasks such as the original marshmallow task in its original form fail to show this flexibility in children's inhibitory skills. Given the important role that contextual factors can have in modulating or changing a child's performance on this task, it may mean that a particular measure is quite an inaccurate assessment of pure inhibition or inhibitory control abilities.

It may instead be assessing the context in which you're measuring in their inhibitory control, rather than their inhibitory control itself. And this would lead to different outcomes. Okay, finally, let's look at how inhibition may be measured in older children of more primary school age. The task I'm gonna focus on was developed by Caragon Nation, although it's been used across a number of different contexts for many decades. So this is just an updated version of this type of task, the stop signal task that they developed to be suitable for use in children. So the stop signal task involves children being asked to press a particular button when they see a particular type of stimulus, so let's say a football, and then they need to withhold a response or inhibit their response when they see a different type of stimulus, such as a rugby ball.

The trials in which children see a football versus the rugby ball are intermixed, with the rugby ball being seen much less than the football coming up on the screen. So they might get into the habit and press football and press the button 10 times and then all of a sudden the rugby ball appears.

The fact that the rugby ball is shown less than the football can mean that it becomes much more difficult to stop that response because you kind of get into the habit of pressing the button, you're automatically pressing it, so children have to quickly learn to stop themselves from pressing the button when they see that distracted the rugby ball.

Some prior studies have found that stop signal inhibition measures for children around eight years old show actually quite mature adult like abilities on this task meaning they seem to be at eight years old as good at inhibiting their responses as adults. Other studies however have found that children do not reach this age until, sorry, not reach this level of performance, adult-like performance, until much later ages. In Craig and Nathan's study they hypothesized that it may be that what's changing and improving across childhood and adolescence is the speed with which an individual can activate their inhibitory control.

So that is to say they have inhibitory control, they can do this at eight years old and we get better at using these abilities as we get older, as we develop. And to examine whether this was true or not, they examined whether inhibition speed can be seen to increase between the ages of five years and 11 years old.

In their version of the stop signal task, children were required to continuously hold down the left mouse button.

So this provided a baseline response ensuring that the child was actually and actively involved in the task, rather than assuming that a no-response trial is purposely withheld, so having to do something no matter what the trial type.

When the children then saw the football appear on the screen, the children needed to release the button and press the, release the left button and press the right button of the mouse, and these were considered the go trials. When the rugby ball appeared on the screen, children should keep pressing the left button down and not switch to the right button, and these were the no-go trials.

So the tarts measured the accuracy of participants in terms of whether they were able to keep their finger pressed on the left button when the rugby ball appeared. The results showed that older children between 9 to 11 years old had significantly better inhibitory control compared to the younger children aged 5 to 8 years old. Of particular interest and the kind of novel insight from this study though was this wasn't just a case of whether they can inhibit or not, instead the results showed some kind of intermediate results as well. For example, and this is kind of the key point of this study, the older children aged nine years and up showed less partial inhibition trials than the younger children on the NOGO trials.

And what this means is, when the rugby ball appeared on the screen, the older children were better at keeping their finger pressed on the left button, they didn't move it at all. Whereas the younger children may have started to lift their fingers so the pressure was off, they weren't pressing the left button before recognising and stopping their action. So that is to say if we just had they had to press a button or not we would only know when they do or do not successfully press the button.

Our younger children here five to eight years old are showing some evidence of inhibitory control because they're not switching to press the right button but they're not able to completely inhibit their response because they are lifting their finger off of the left button and so it seems that at younger ages although we have possession of inhibitory control we're not completely activating or completely ready to respond to that inhibitory control until a slightly later point, a delayed point compared to our older children. And so again, this shows that kind of intermediary development of inhibitory control where you're able to do a thing, but it's taking you longer to get there than at younger ages compared to older ages.

It seems then that Claggenation's prediction was correct.

As children get older, they get better inhibiting actions at an earlier time point in the response process, becoming more efficient at inhibiting proposed motor responses.

This study did report that despite these observed improvements in inhibitory control, older children were not yet performing at adult-like levels, so they're not as efficient as adults still despite this improvement seen.

Taking together these results indicate that inhibitory control can be developing until quite late in childhood and indeed some of my own research has suggested that we continue to develop inhibitory control inhibition up until around 35 or 36 years old and so it's not a case of we're developing inhibition abilities in childhood and as soon as we've got them we've got them they continue to change and evolve across young adulthood and into I'm going to say 35 is still young adulthood so into early 30s we'll say it like that and then they gradually decline as you get into older age. Okay so let's pause here to reflect on what we've learnt in this first section. The term executive function refers to this family of different abilities which are utilised for the planning and implementation of goal-directed behaviours. Executive functions are typically associated with frontal lobes and the importance of executive functions can be particularly illustrated by investigations and case studies of individuals who have experienced frontal lobe injuries. There is general agreement that there are three core executive function abilities including inhibitory control, cognitive flexibility and working memory, although it's noted that other abilities such as planning may also be involved as an executive function or it may be a side effect of these three executive functions. Inhibition or inhibitory control refers to the ability to stop pre-potent responses or pre-prepared responses and to resist distractions allowing individuals to focus their attention on a particular goal or task. Three key measures tell us about the development of inhibition come from studies looking at inhibitory control at different ages. In infancy, Holmland colleagues used the looking times in the freeze-frame task to measure infant's ability for inhibitory control, and they suggested that inhibition capacities begin to emerge and develop from at least six months old. At preschool age, we see a delay of ratification tasks such as the marshmallow task, have suggested children at this age struggle to inhibit their desire to gain a sweet or an edible reward in the form of eating a single marshmallow rather than waiting to get the increased number of marshmallows at a later time.

However, further research has shown that performance on this task can be context-sensitive, such as whether a child has learnt that a researcher is reliable or unreliable, and indicating that we may need further measures to fully understand what's happening with older or primary school-aged children, Okay, before we go on to, before we have a break, we're going to switch over to Mentimeter again and do a couple of quiz questions and then we'll have a break for the second thing. So if you want to get onto minting into please, a few more people get logged in. Okay, so let's do some quiz questions from the first half of today's class. This is a good measure of executive function actually.

This is a good measure of executive function actually. Executive function can be best defined as bottom-up lower order processes, bottom-up higher order processes, top-down lower order processes or top-down higher-order processes? Which of those is the best definition of executive functions? Excellent. Yes. So top-down higher-order processes, the picture in that kind of CEO of a business, looking down all the other things and work, not looking down, working with all of the other people at different levels to try and instruct them in order to achieve an overall goal. Excellent. Next question. Delay of gratification tasks are most often used to assess inhibitory controllabilities in which particular age group?

in which particular age group? Newborns, young infants, preschoolers or primary school age? Hopefully this is a hundred percent question. Okay, so delay of gratification tasks are most often used to assess inhibitory controllability with preschoolers.

Yes, slightly out of that young infants, this is now children that can actually use their motor responses and engage with things but before they get to primary school where we know inhibitory control is present. Which of the following is not an example of inhibitory control? Blurting something out without waiting for someone to finish speaking, taking a deep breath when angry instead of yelling, thinking something funny during a serious moment but not saying it, or waiting until after a lecture to get a drink. which is not an example of inhibitory control. Excellent. So if we're saying something that we maybe shouldn't be saying in the context, that would be that we have not engaged our inhibitory control, whereas all the others choosing to take a breath instead of yelling, thinking something funny, but realizing this is not the moment to say it or waiting until we finish the section of the lecture before eating a drink would all be engaging inhibitory control. Excellent.

Two more questions in this part. Cracking nation stop signal tasks suggested that inhibitory control is fully developed in early childhood, continues to develop into late childhood and continues to develop into adulthood. This is a slightly trick question, so please be careful to read what the question says.

says. Cracking nation stop signal task suggests that inhibitory control, which one of those is the best summary?

is the best summary? Okay, so the reason this is a trick question and the reason that the continues to develop into late childhood is great. I did mention that it continues to develop into adulthood, but that was my research. The cracking nation stop signal task is talking about their study and they only had children up to 11 years old, so they cannot comment on what happens into adulthood and therefore the correct answer is they've shown it develops into late childhood, they don't know what happens, it could be at 12, they're all fully done and ready to go. So that was a little bit of a trick question, but maybe it's helpful for when we're reading exam questions and things like that, to remember to actually check what it says. This last question, I've put a correct answer, but actually this is more of an opinion. I wanted to know whether you think, and particularly based on evidence discussed in lecture, do you think there would be greater differences in inhibitory control at five years, there'll be gender differences, sorry, gender differences in inhibitory control at five years old? Do you think that boys and girls at five years old have differences in inhibitory control capacities? interesting a lot of you say yes why do we think yes there was no correct answer as I say this is an opinion it's interesting but I thought it would be a good moment to watch this video so I don't know how many of you've seen the secret life of five year olds or the shorter the secret life of four year olds it's a little bit old now but this is where they have children of four five and six years old in these nurseries that are being videoed obviously with parental permission and things like that and in this one they're looking at people's moral compass, so the development of the moral compass, but I also think it's a really nice illustration of gender differences in inhibitory control.

It's not a scientific study, but have a go, well after this video we'll have a break, but have a think, have a look at the gender differences in this. I'm just looking at it.

It just looks delicious. She's a elf.

No, I didn't eat it. The girls managed to resist temptation and leave the cake alone. now for the boys this is just olives cake for later okay so in that sort of situation what you really need to do is to get away from the source of the temptation and some boys did that what Alfie did was the worst thing possible which is to sit myself over the cake and smell it and look at it. This makes my mouth full.

That looks yummy. I love chocolate. It smells chill. Yummy.

Smell the cake. Smell the cake. Oh, he's eating it. No, I just took an egg.

That's all. I love the fact that touching the cake or altering its appearance in any way is treated with moral outrage by our group of boys, but licking it isn't. And I think this tells us something really important about their moral world. They don't care about doing wrong, but they do care about getting caught. So the illustration in there, of course, this, as I say, it was not a fully scientific study, but suggests there may be some differences, but what they were looking at there is that moral outrage, so that level of what we can do, and as they were mentioned there, the kind of getting caught versus not getting caught, but it's interesting to see the differences in how the girls versus boys at those ages were looking at. Okay, let's take a 10 minute break. Now we'll come back at five past. If you have any questions, please move to ask or put them up on here and I'll see you in 10 minutes. Before we get started again, I've got to say at the beginning, somebody has pointed out that the audio isn't working on the first recording of the cognitive development seconds or two weeks ago. I will try and upload a different version. For those of you who are trying to watch it, so apologies, it might be last year's one. So if you're doing last year's one and I mentioned coursework or anything like that dates, please very panic. Everything is still the same as this, but just just to flag that.

Okay, so in the next part of today's class, we're going to be talking about the two other executive function components, cognitive flexibility and working memory.

Let's start by looking at the capacity of cognitive flexibility.

Cognitive flexibility is also sometimes referred to as shifting, and it refers us to our ability to modify our current goals and to plan in various ways by adding new rules or perspectives and adjusting to new demands in an old situation.

So in other words, cognitive flexibility allows us to switch between different concepts or to think about multiple concepts simultaneously.

This may require applying new rules to a familiar or known situation, allowing individuals to adapt quickly to changes or new situations and allows us to tolerate and adjust to change demands of different situations such as when problem solving or carrying out a task allowing you to create alternative solutions to current contexts. If you're trying to do something that's not working, flexibly switching to something that might work. Sorry.

Cognitive flexibility also allows individuals to change perspectives, seeing things from different points of view which in turn may allow them to more easily established solutions or compromises to particular problems that they're presented with. There are many different ways to measure cognitive flexibility in a number of different tasks, but one of the most commonly used ones is the Wisconsin card sorting task pictured here. This task is most often used with adults and in the task participants are required to sort the cards according to different dimensions or different rules. So this could be number, shape, colour and throughout the task the rule will change without the participant being told. They get feedback on whether what they're doing when they're sorting them is correct or not and the participant needs to flexibly adapt to the new rule to get the answers correct to work out what the rule is and then to follow it. A simplified version of this task has been developed for use with children and this is called the Dimensional Change Card Sort Task or DCCS. An example is pictured here, so in this simplified version of the task, children have two potential rules, color or animal or shape, I should say, color or shape to match the objects by. So they could be matching it by blue and blue of the bunny and the boat, or it could be that they need to match the shapes of the two boats and ignoring the rabbit. We're going to zoom in on this particular task or these types of tasks of cognitive flexibility in a bit more detail. So in the classic version of the dimensional change card thought task, children are shown a set of two cards turned up like this and in cards one and two, they have two dimensions. So you have the shape, star versus diamond, and you have the colour, the red versus blue. Children need to work out what the rule that they're actually following is.

They're asked to sort the pile of cards over here on the right hand side, according to the different rules which they have to work out to try and establish what the rule is. So for the first few trials they may need to use trial and error to see what the correct dimension to classify the cards by is and if they identify that they first need to sort out the cards by shape they would then keep doing that for an unknown number of trials that says unpredictability introduced and then suddenly the rule will change to being they need to be sorted by colour. What we look at in these types of tasks is how quickly children can adapt to a new rule and how quickly they can work out what that new rule is. Results have shown that typically children start to pass this version of the task at around the age of four or five years old, suggesting development of cognitive flexibility capacities around this age, so they're able to flexibly switch to follow different rules when sorting the cards as appropriate by around four years old. Three-year-olds, in contrast, tend to be unable to flexibly shift to the new sorting rule, continuing instead to sort the cards by the originally established dimension, such as in our example, sorting the cards based on shape rather than colour, for example. And this is an example of a preservative error, where the three-year-old children are continuing to respond to an old rule, even though this rule is no longer correct. They're made aware that the rule is no longer correct. They're given accuracy feedback in the task, and yet they still make these errors, still continue to do this. And so the question becomes, why aren't children able? Why are three-year-olds making these errors at this stage, if they're aware of the rules? We know that children can understand the two separate rules, in that if you simply tell them to sort the cards by shape or by color, they are able to understand that and do as appropriately. Indeed, they're even able to explain the two separate rules if they are asked to do so. It's also been shown that they can pass these types of dimensional change card sort tasks if they're presented with more than just two colour options. So if, for example, the cards are red, blue, yellow and green, children seem to be able to pass the task. And so it can't be then that the number of options, whether that's colour or shape, is preventing children from succeeding on the task instead something else is happening.

So adding more options in terms of the colour or more shapes allows them to pass the task.

So that so in colleagues suggested it may be that at three years old children lack the ability to look at one thing in more than one way from different perspectives.

So depending on the situation they're unable to think about something in more than one way because this involves reflection or the ability to detach from reality which they've not yet developed. And following these suggestions, Zalatso and colleagues developed a theory that may explain these feelings, these findings, not feelings, sorry, these findings. Zalatso and colleagues proposed something called the cognitive complexity and control theory. This theory suggests that what makes a task complex and what may therefore prevent children under four years old from succeeding on the task is the use of a hierarchy of different rules rather than the number of rules.

So that is to say it's not just that we have rules to follow to complete a task but these rules have a hierarchy.

Higher order sets of rules are much more challenging to use according to this theory. So in this way the cognitive complexity and control theory suggests that to make something more complex it's the number of degrees of embedding that need to increase. In other words, it's the levels of hierarchy rather than number of individual rules associated with the task. The way something becomes more complicated then is not just regarding the number of choices that are at one level. So I can add as many shapes as I want, that's at one level and that's easy to do because there's lots of different shape options but I'm still focused on shape. That's not going to increase the difficulty of the task. What is going to make the task more complicating is when a higher order rule is created such as creating if this then that rules. So for instance if the rule can change during the task such as in this, so we start by sorting by color and then we're going to switch to playing by shape, the dimension on which we've classified objects has changed. So then in order to be successful, children need to keep in mind different sets of sub rules in order to pass the task. If we're playing the shape game, then I need to organize by this. If I'm playing the colour game, then I need to organise by this. Is this embedding or this hierarchy that these authors argue increases the complexity of the task for young children? It involves the ability to look at a single card in a number of different ways depending on the game being played at any given point in time. This ability of reflection, of observing something from multiple perspectives, has been suggested to be related to other things such as false belief reasoning and counterfactual reasoning in which again we need to be able to reflect on things from different perspectives or different viewpoints how somebody else can see something versus how I can see it and indeed the age that children start to pass counterfactual and false belief reasoning seems to align with when they develop these more flexible cognitive flexibility skills so they're developing this perspective shiftings cognitive flexibility around the same age.

The as card sorting tasks used to assess shifting or cognitive flexibility is typically passed around four or five years old. So prior to this, at three years old and below, children are struggling to pass the task, although they're able to understand the individual rules that underlie the game. So they can compute and follow individual rules, but not when they're embedded in this higher order structure. However, relatively recent results have found that much like with inhibitory control abilities, children's shifting abilities can be altered by context, they're sensitive to contextual cues.

So back in 2015, Dobel and Zalatsu conducted a meta-analysis, a review of literature using this card sorting task, the DCCS, to identify key contextual cues that may influence a task performance.

They found that the number of trials before a rule switch took place could influence results, so the more trials that happen, in, let's say, sorting by shape, before they then switched to a colour rule, led to worsening performance by young children.

They also found that studies where children were given verbal cues to highlight the conflict between the two sets of rules. So if the researcher said something like, look at this from different perspectives, or look at this, it's a blue star highlighting those things.

When you emphasise the presence of a rule switch, it made the child we were sorting by colour, now we're going to sort by shape or vice versa, that seemed to help the child switch to the new rule.

And they also found that how the card was labelled could also influence the task performance.

So if the card was only labelled at the beginning by its target dimension when they turn it over, so look this is a blue card, rather than by including both dimensions, this is a blue star or a blue boat, this increased children's performance on the task, so keeping it restricted to the actual topic or the actual thing being targeted, so blue versus another colour, in that moment improved task performance when the rule switched.

So it seems then that cognitive flexibility, much like inhibitory control, can be influenced by task context and so this needs to be considered when we look at the developmental trajectory of these abilities. So once again, we can't do or give a task to infants at three, four and five years old, and then whatever their performances assume that tells us everything, we need to take into account the factors and context that underlies that. Okay, moving on to working memory then.

I'm not going to say too much about working memory because we're going to cover this in much more detail in next week's lecture, but we're going to dip into it today because it is an aspect of executive functioning.

So working memory is sometimes referred to in the literature as updating, which in most places that we refer to as working memory, but if you see updating, that's what it's referring to. And working memory or updating specifically refers to the ability to hold information in your conscious mind to allow it to be used. It is separate from long-term memory. It's not necessarily something that we have and can remember for a long period of time. And it's also not short-term memory because working memory involves this active component of holding information in mind to allow it to be manipulated for a particular purpose.

Working memory is purposeful, it's not for instance if I see somebody walking along the corridor over there for a very brief moment in time I might remember their face but then it's gone, it's irrelevant to me I'm not paying attention so I'm not actively trying to hold it in my mind. If I see someone and I want to remember their face and I'm actively trying to hold that in my mind that would be worth your memory. When we try and purpose the whole piece of information in mind to allow us to achieve a particular task, this is what is involved in working memory. For example, if we're trying to follow along with an argument and people keep talking, you're thinking, I need to come back to that point. So you're actively keeping that in mind. If you're trying to do some mental arithmetic or even if you're reading a sentence, you need to keep in mind the first part of that sentence as you're reading the second part of the sentence to make sure that it's clear and understood. You need to know what you're reading makes sense. So working memory classes are extremely important. They allow us to engage in many daily activities to follow through on things and know what it is we're trying to do at any given point. This picture here is of Badly's working memory model, which is a very popular model of working memory in the literature. I'm not gonna talk through it today because we're gonna go through this in much more detail next week. But I wanted to put it in because when it comes to revision, just to highlight that this is very much linked to what we're gonna go through next week. Okay, so let's have a think about working memory abilities in children and how we might assess these.

To test working memory, tasks typically involve asking participants to see or hear a set of information such as words or numbers, which need to be both remembered, recalled, but also manipulated in some way.

So this is how we make sure we're actually tapping into working memory abilities rather than anything else or different memory capacities. For example, in the backwards digit task, participants may be presented with a set of numbers and they're then asked to recall them in reverse order. So there can be easier trials like 247, which would be recorded as 742, or they can be more challenging involving numbers such as 587-601 and we could ask people to recall them in reverse order, so 106-785. A really terrible or mean researcher who wanted to really push working memory to its capacity may present 587-601 and then ask the participant to report them in chronological order or reverse chronological order.

So it's that manipulation of the data rather than just holding it in mind. I personally have a really terrible working memory so I do terribly on all these types of tasks but some people have expert working memory and can do all different levels. So again we have lots of individual differences in working memory abilities.

Another measure of working memory is the Coursey of working memory.

In this task participants are showing a grid like this. They observe different blocks light up and then they're asked to recall the order of the blocks or the reverse order of the blocks to see how well they can remember the order that they lit up in. If anyone wants to have a go at that then on the slides on my Dundee I have put a link for you to see an example of the task. Okay as I mentioned a moment ago working memory is not the same as short-term memory. There is both a, this is both in terms of their functionality, but also in terms of their developmental trajectory. For example, Diamond, Adele Diamond has presented evidence that suggests that working memory develops both later and more slowly than the development of short-term memory. We're going to look at some of the factors that may influence working memory development and how we can actually assess this across different cohorts. Working memory is often stated to be related to other individual abilities such as executive functions more generally as well as intelligence or IQ.

It also seems related to other more generic cognitive capacities such as language abilities. And in this study back in 2013, Morales and colleagues conducted a study with five to seven-year-old children who were even monolinguals speaking just one language or bilinguals speaking two languages.

And they found that bilingual children significantly outperformed monolingual children on the measures of working memory, even when different task demands were controlled for. So that is to say, this isn't just a feature of the tasks that we use, but actually bilingual children seem to have enhanced working memory abilities when compared to monolingual children. And this is an effect that is found across older and older childhood and even into adulthood. So two people that can speak more than one language tend to have better working memory capacities more generally than those who speak only one language. Although, as a side note, it doesn't seem to be that if you speak more than two languages, you don't continue to get those improvements. It's that bilingualism and further still has that effect. As I mentioned, I'm not going to go into great detail about different memory components, as we'll look at those more specifically next week, but I did want to flag this study by Alaway and colleagues, because it's an important one for the working memory literature.

They wanted to examine the presence of potentially different working memory components in children between the ages of 4 and 11 years old.

They suggested that the structure of working memory and memory in general as we observe in adults is already in place by 4 years old. So according to them at 4 years old you have the memory structures that you're then going to be using for the rest of your adult life.

If this is the case it would suggest that structurally children and adults do not have different forms of memory, suggesting that memory in its mature form develops very early on, reaching potentially adult-like levels in terms of structure by four years old. The capacity, efficiency and flexibility of this memory mechanism may continue to develop, so they're not saying that four-year-olds have exactly the memory that adults would have in terms of its efficiency, but the core structure seems to be present, according to Alaway colleagues.

I'm not going to go into any more detail on this yet. We'll talk about this in more detail next week. So does a four-year-old have the same working memory structure and memory structure as an adult? So it's a cliffhanger to keep you going for next week, but something to link here with the literature. Sorry, I'm going to take that off while you're Diamond suggests that executive functions play a really important role in explaining A0B search errors.

Diamond argues that both inhibitory control and working memory are required for an infant to successfully perform on the A0B search task, so remembering where an object is hidden and then reaching for it in a new location. Both inhibition and working memory are required in the A not B task, as suggested by the finding that children can inhibit their long lasting memory of the object's previous location in order to search for it in the new location, location B, but only for a brief moment of time. So that is to say, the longer you make a child wait in the A not B task, the longer or the more errors they make. If you do an immediate change and then let them reach, they can actually find it.

The longer the gap between a toy being hidden and a search opportunity, the more likely the child is make a search error.

And Diamond argues that this is because the memory of the object being hidden at location B is a relatively fragile thing for infants to hold in mind, and children have not yet got strong enough for lack of a better expression, that executive functions to allow them to keep this continuously inhibiting the memory and keeping this in their working memory.

And so according to Diamond, over time the working memory structure is kind of to actually keep a memory actively in their working memory. Looking at the development and emergence of working memory and inhibition abilities, Diamond therefore argues that this strengthens her suggestion with executive function development aligning with task performance on the A0B task, indicating that executive functions, as she argued, executive function development can explain A0B search areas seen in early infancy. She documents that infants, even in their first year, can successfully inhibit their responses in an A, not B search task, but only if they're able to search for the object in the new location without a prolonged delay between the hiding event and the search opportunity. This suggestion, which is that executive functions drive performance on a particular task, allowing children in certain circumstances to pass tasks prior to their first birthday. In this contrast with Piaget's view of infant performance on the task, given that he argued it would be impossible for them to do this until later ages. So in other words, A0B task performance, according to Diamond, is not actually to do with whether the infant is able to follow where an object is hidden. It is about their executive functions of keeping the new location in their working memory and inhibiting a response, which counters Piaget's argument. Okay, let's pause again here to summarize what we've covered in this section. First in regards to cognitive flexibility. Cognitive flexibility refers to the ability to look at stimuli from different perspectives as well as flexibly implying new rules to familiar known situations as appropriate. These abilities can also be referred to as shifting and is often assessed in preschool aged children using a dimensional change card sort task in which children need to sort cards based on different dimensions. The cognitive complexity and control theory proposed by Zelaso suggests that prior to four years old, children are not yet able to pass this task because they're not yet able to embed higher order rules such as understanding the if this then that type of relationships. Because according to them, this requires development of the ability to engage in reflection, viewing things from more than one perspective, such as the object on this card being both blue and a star at the same time. Looking at working memory, working memory refers to the ability to hold information in mind and to use it to achieve a particular active and current goal. This capacity can also be referred to as updating. And working memory differs from short-term memory with working memory developing both more slowly and at a later time compared to short-term memory. Diamond argues that it is the development on emergence of both working memory and inhibition together that enables infants to learn to succeed on tasks such as the A0B search tasks, and we'll talk more about the development of memory in its different forms in next week's lecture. Okay, before we move on to the final part of today's section, let's go back to Mentimeter for a moment.

Okay, so we've got a few more quiz questions on working memory and cognitive flexibility, and then we've got the last section on executive functions. I'll just let you get logged in.

Okay, let's get started. So first question, cognitive flexibility allows individuals to resist distractions in the environment, adjust the changing situational demands, do mental arithmetic.

Which of those is the best definition of what cognitive flexibility allows an individual to do.

Excellent, yes so cognitive flexibility allows us to adjust to change the situational demands and switching what we need to focus on at any given point. The cognitive complexity and control theory says that cognitive flexibility tasks get harder when the number of response options increase, verbal cues are used, or the number of higher order rules increases, which of those is the correct option? Perfect, yep, so the number of higher order rules for the more embedding, so that if this, then that kind of rules, they seem to make things more complicated, whereas actually increasing the number of response options increases performance positively for preschoolers. All right, an ultimate question.

Which of the following characteristics is not an example of work in memory, the ability to hold information in your memory to be used, the ability to remember a journey you took some time ago, the ability to read sentences or the ability to follow arguments.

So not an example of work in memory. Excellent.

Okay, so not an example of work in memory, the ability to remember a journey you took some time ago, that would be a longer term memory because I remember it from some time ago, reading sentences involves that work in memory because we're holding a sentence that we're currently reading in mind so that we can understand it in context, following arguments, remembering what someone's just said, so you can respond to them and things, and holding information in your mind to be user active component.

Excellent. Okay.

Last question. Speaking more than one language in childhood. Hopefully we can all get this one. Improves working memory, decreases working memory, has no effect on working memory.

So speaking more than one language in childhood.

Exactly. Improves working memory. So if you're raised speaking more than one language, we see an improvement in working memory capacities compared to those who are monolingual. Excellent. Let's have a look at the leaderboard. Oh, it's quite close today.

Excellent. Congratulations to B. Okay, I will leave the question board up here.

Before we move on to the final section, does anyone have any questions about what we've talked about so far? either on here or in person. Okay, I will leave the question box open, so if anyone wants to submit questions, please do, but rather than standing here silently, I will go back to the slides. Okay, so last section.

In the final part of today's class, we're going to look at the overall structure of executive functions.

And what I mean by this is, rather than looking at the three individual executive functions that we just talked about, we're going to look at the different abilities to see whether they're actually the same thing, we're just looking at different sides of them, or whether they are entirely separable abilities.

So I mentioned earlier, when defining executive function, that there is some disagreement in the literature as to which abilities should be included under the umbrella term of executive function.

So there is mostly consensus around the idea of inhibitory control, working memory and cognitive flexibility being three core capacities of executive functions although there are some people that say actually they're all the same thing or other people that say that there's more than just the three of them.

There's also another debate in the literature regarding whether the three separate components or three components do reflect separate abilities or whether they're actually just different expressions of one common underlying executive function.

executive function. In other words given that in different ways each of these executive functions are argued to more generally help with goal-directed actions, are they reflecting one unitary concept where executive functions are one overarching capacity, which would mean that they use the same brain regions and develop in the same way across different abilities, or are they separable distinct abilities that are captured by this umbrella term of executive functions? Are they distinct abilities or just two sides of the same coin?

the same coin? Duncan and Colley stated there are actually quite low correlations between different tests of executive function deficits when examining patients with different types of brain injuries.

In other words, they found that patients could be impaired on one aspect of executive function, let's say inhibitory control, but could retain relatively intact if not completely intact other executive function abilities such as working memory.

And this finding seems to indicate an open and shut case. if it's a case that I can have a problem with one of these but retain the abilities in the others, this suggests that different executive function capacities must be relatively independent of one another. It would seem then that we don't need to utilize the same underlying process it says when recruiting different executive function abilities. However, once again, the story isn't quite as black and white in that. Because this study also reported that for each of the tests of executive function capacities, Patients' performance on these tasks correlated with their assessed level of fluid intelligence. So fluid intelligence, as opposed to crystallized intelligence, has been suggested to be linked to an individual's problem-solving abilities. This relationship indicates that there is some sort of common ability underlying performance leading to this similar relationship across different types of executive function. And just for clarity, fluid intelligence is your ability to process new information and learn and solve problems, whereas crystallized intelligence is your stored knowledge accumulated over the years.

So these two types of intelligence, fluid and crystallized, work together and are both equally important, but one is kind of what you already know and one is your openness to acquiring new information.

So the question became then, could it be that fluid intelligence is the key ability that's underlying each of these executive function capacities. The short answer is we don't actually know because evidence is really mixed. Although people with frontal lobe injury do show reduced performance or measures of executive function as I mentioned, there is also evidence that individuals can be impaired on one task but not another.

And this again highlights that there must be at least some level of independence between different types of executive function abilities. This leads us to the idea once again of the task impurity problem. I mentioned this first a couple of weeks ago in our first lecture about Piaget's theory of cognitive development, and this is a really important issue to be aware of in psychology literature. The task impurity problem refers to the need to be aware that most psychological tests, in fact almost always, measure more than they're meant to measure. So that is they rarely process pure.

For example if you're doing a lot of online research during COVID almost all studies were online.

It's difficult to know whether we were measuring stroke task performance but were we measuring it based on how noisy the environment was, how quiet the environment was, we have no idea what factors may have been going on in that background.

We couldn't control it as opposed to it's in a lab and we can have a more controlled environment. So therefore we could indirectly be measuring the impact of doing a study in the living room versus a bedroom versus at the kitchen table with lots of people around.

Executive functions are particularly susceptible to this task impurity issue.

In particular this is because they're all involved in execution and regulation of goal-directed behavior and therefore it's very difficult if not impossible to assess any of them completely in isolation or in a vacuum.

So again if we think of the street color word task as a measure of inhibition for example it's aimed at looking at how well we can inhibit our want to just read the word and focus on the ink color but we also have to use our working memory to keep the instructions in mind to remember what we're trying to do in this task which is read the ink color and so by although we're measuring inhibitory control there's a working memory element because we need to remember what the aim of the task is and what we're trying to do when responding.

When testing executive functions, we need to get people to do something, a task, in order to figure out how they may regulate themselves whilst they're doing it. So we therefore have to balance our task design with the risk of this task impurity issue.

To try and address this, executive function tasks usually utilize novel measures asking people to do things that they're not familiar with.

And this is because executive functions are specifically involved with conscious effortful control.

We do not need executive functions to deal with habits.

For example, if you think about how you put your shoes on, you probably do not have to effortly control your actions and explicitly figure out how to tie your laces together once you've learned how to do this. For most adults, tying shoe laces is a habit or I had a meeting with a student earlier and when you, I have a Mac, and when you're doing the kind of shortcuts and you're copying and pasting things here and I do it so habitually that when they say to me, when someone says to me, what do I press? I think I have absolutely no idea and you have to really concentrate to remember that. So we don't need our executive functions for these habits we've already established. We need them when we're doing these more effortful conscious processes. Once something has been performed enough times, you get more efficient at doing it, you no longer need this effortful control to do that thing. For executive function research, this means that in order to get an accurate measure or assessment of people's effort for conscious control, we need to get to them to do something new, something they're not familiar with.

Back in 2000, Mayaki and colleagues published a really important key paper in executive function literature.

If you're going to read any papers from the this lecture, I really suggest this one is a really important one to read.

What they were interested in is the question of whether executive functions are unitary or separable components.

They wanted to try and establish this by also combating the issues with task impurity.

So to address the task impurity problem, that is the problem of measuring executive function tasks and potentially measuring more than it's meant to measure, they had their participants each complete a large number of tasks measuring different aspects of executive function and measuring different aspects of executive function across different perspectives.

So using multiple different tasks to assess inhibition capacities rather than just one measure of inhibition.

In using this approach they argue that the different tasks would measure different aspects of executive function and that performance on each task should vary but only due to different task demands but also the participant's abilities. So you might get some small variation across let's say three measures of inhibitory control but you also might if you have a participant that's really good at inhibitory control they should be good on all three tasks and if they're really bad at inhibitory control they should be bad on all three tasks.

They argued that by running lots of executive function tasks, they'll be able to see if this is true, if people's performance on various tasks of common abilities tend to correlate.

So that is to say, do all three measures of inhibitory control, are they more closely related than measures of cognitive flexibility or work in memory? They then used factor analysis to determine how different executive function components measured in their task battery may relate to each other in an adult sample of participants. Okay, so I know there's a lot of numbers on this slide, but this is a factor analysis. And factor analysis looks at the performance of participants across a number of different tasks to look at whether performance across the task can be explained by different constructs or factors. So in this particular study, the constructs or factors that they were interested in were our three executive functions. so the cognitive flexibility or shifting, working memory, updating, and inhibitory control or inhibition.

And these were the results from my achiatale study.

So on this figure, the relationship between the different tasks, we've got the correlations between cognitive flexibility and working memory, working memory and inhibitory control and inhibitory control and shifting, denoted by these lines here.

And then you've got the loading factors of the, these are different tasks, so three measures of cognitive flexibility, three measures of working memory, and three measures of inhibitory control. This is how much they related to each of these, and these are broad correlations.

So the arrows on the side show the correlations between the different types of executive function abilities, and the other lines are showing how much variance is predicted by each of the three components.

And I realize there's a lot of numbers and things going on in this figure. But in essence, what Mayaki and Colleagues argue is that the best fitting model for all of these nine tasks that all the participants did is this three structure model of executive functions.

That is to say the tasks as expected, the tasks that measured cognitive flexibility loaded onto this cognitive flexibility or shifting factor, the tasks that were meant to measure working memory or updating loaded onto updating and the same with inhibitory control.

And what this data means, according to my acting colleagues and many other research since is that although these three factors are closely related they are independent abilities. You can have inhibitory control that's really good but have working memory that's not good and have cognitive flexibility that's somewhere in the middle. They are three related but separable abilities.

A particular strength of Mayaki and Colley's paper is that they were able to evaluate several different models in their study.

They had enough data so they looked at whether the best way of describing the data was to view it as one general executive functionability or three completely independent abilities.

And this analysis approach is particularly strong as it allows overcoming of this potential task impurity problem by using a number of different tasks for assessed performance. They're not relying on just one measure of inhibitory control or other, instead they're looking at multiple factors. And as we just saw, the model that had the best fit to the data was found to be the one that had three separable executive function components identified as working memory, inhibition and cognitive flexibility. And the authors argue that these were shown to be related but separate capacities, meaning one could show a deficit in one whilst the others were spared. Now we're in a developmental course and development continues across the lifespan, but Mayaki's paper looked at the structure of executive function in adults. And so that leads us to the question of what about in children? What do executive functions look like in children and are they structured in the same way? So to examine this, Stephanie Carlson, who is pictured here, conducted a very large-scale review of different types of executive function tasks used with children between the ages of two to six years old. Her aim was to see whether children succeeded on some tasks at earlier stages of their development compared to other tasks, and what the implications of this would be in terms of our understanding of executive function development and structure in childhood. And so for this paper, she reviewed a wide range of previously published papers leading to a total sample size of 602 children and 24 tasks being used in the analysis. Carlson found that children did not seem to develop the ability to perform some tasks before others. So this suggests that tasks were of equal difficulty for them at different ages. Specifically, there was no difference found in the age of the emergence of the ability to pass measures of inhibitory control or working memory.

So if they could pass one, they could pass the other. If they couldn't pass it, they couldn't pass the other. And so it seems that it did not seem that children found one type of task such as inhibition easier to complete than another task such as working memory or vice versa.

So this indicates that capacities for both inhibitory control and working memory are emerging at around about the same time. One doesn't have the edge or develop earlier than the other.

Carsten also reported that tasks which require participants to use both of these executive function abilities, so working memory and inhibition, were found to be the hardest for children to complete regardless of age. So they could pass tasks, even once they started passing tasks that were meant to be measuring just inhibition or working memory, but they were able to do that. If they were then asked to do a task that combined the two, they found those a lot harder and would still fail them for quite a while.

So Carson, as I say, identified that tasks requiring the use of multiple executive functions were the most difficult for children from two to six years old. She identifies here the specific tasks that children found hardest to complete at various ages and as we can see, so the reverse categorisation, the dimensional card change thought in task which we've looked at, backwards digit span, Simon say so this is where you have to flexibly adapt to different rules and change what you're doing. Each of them is requiring multiple executive functions to correctly interact the task, inhibiting a proponent response, remembering the new rule and flexibly switching between those rules. I'm not going to go into more detail on that, you can find out more from the paper, but it's really interesting to see what kind of tasks infants were or children were struggling with at different ages. The important take home message of this though is that Carlson highlighted that children did not find one particular type of task to be any easier than the other at any of these ages, suggesting that their ability for inhibition and work in memory are emerging at the same time, and this differs from our adult literature where you can be good at one and less good at another. So given these findings where children's ability to succeed at different tasks seems to emerge at the same time, they don't pass inhibition before for working memory for example, Carson suggests that in young children, unlike in adults, executive function abilities may not actually yet be differentiated.

actually yet be differentiated. Young children's executive function performance does not vary much based on the type of ability they're tested on, and this could mean that these abilities are not dissociated to the same extent as they are in adulthood. Indeed, perhaps executive functions first develop as this kind of unitary idea which only becomes differentiated as age advances and develops into the more mature abilities that we see in older childhood and adulthood. Why might this be so?

Why might this be so? What could be driving this? It kind of seems odd to think that we would have this massive developmental shift where we learn and acquire executive functions and then another one where they start to differentiate in older age or become more specialized.

Well the suggestion is actually not so strange if we look at the biological factors that may underlie these developments.

Executive function abilities as we said earlier have been related to the prefrontal cortex and it's well documented that this region of the brain undergo substantial change to its structure throughout childhood.

It's perhaps not implausible then to suggest that executive functions may become more and more specialised as the underlying brain structure, the neural structure in the prefrontal cortex, also becomes more efficient and specialised. And this suggestion has been further supported by a study by his urine colleagues. So similar to Mayaki and colleagues, they wanted to examine the goodness of fit of different models of executive functions in childhood.

That is, they wanted to see whether, what type of or the three-year factor model of executive function best describes data in childhood. They tested children between the ages of 7 to 15 years old, so slightly older than the Carlson study, and they used factor analysis again to examine potential changes to executive function abilities throughout childhood.

As they predicted, their results found that the best model fit differed between earlier versus later childhood.

For children up to the age around 12 years old, the best-fitting model was the one-factor model, suggesting one overarching executive function capacity or node, whereas for the older children between 13 to 15 years old, this is more akin to the adults where we see a three-factor model as best fitting the data. To take them together, these results further support the idea that executive functions only begin to dissociate, as seen in the adolescents and adults, after around the age of 12 years old. have these maturational changes in the prefrontal cortex and this seems to be leading to the differentiation between the three executive functions. Prior to 12 years old, executive functions are more immature and develop as a unitary executive function capacity. Okay, let's summarise that section.

There has been substantial debate about whether executive functions are independent capacities or just different expressions of one overarching capacity. Miyaki and colleagues argue that in adults, executive functions are separate but related abilities and they used factor analysis to strengthen their results and thus conclusions overcoming the potential for the task impurity problem. Carlson, in contrast, documented that executive functions are unitary in preschoolers only separating into three related components as seen in adults in later childhood.

These findings were supported by Zoom colleagues who found that who argued that the prefrontal cortex develops and matures across early adolescence becoming more specialized and executive functions go alongside that.

Let's see if there's some questions. How does the this is a blue card help the kids pass this um sorry so this is about the dimensional card chain sort cards. How does the this is a blue card help the child to pass the card to sort tasks better than this is a blue star? So what this is doing when we're trying to do it is basically breaking things down for the child so they only have to process in the first one this is a blue card one rule at a time. When we then switch to a new rule you might help them by saying this is the star card so you're guiding them on the shape. Whereas if you immediately say this is a blue star you're giving them those two rules immediately to try and process and so they're not differentiated between that. So the reason it seems to help the children is you're guiding them to focus on one dimension and then reallocate their attention to a second dimension whereas when you say blue star you're already introducing two dimensions, and they're not sure which one is the important one to focus on. Hopefully that makes sense. Anyone have any other questions at the moment? If not, oh, sorry, I went past one. Why are individual executive functions better or worse in adults if they develop as one function in childhood? Individual executive functions better or worse in adults at least. Because although they develop as a unitary thing, so that is our executive function is developing seemingly together in childhood up until around 12 years old and then they're differentiating 9-2-3 abilities. What that is not saying is that at 12 years old you then have your full executive function abilities, they're continuing to change, develop.

So at 12 years old you might find that people are performing similarly across inhibitory control, working memory and cognitive flexibility because they've all matured to a certain level but then you're going to see some differentiation because they're after 60 years old. So even when they're saying they reach a certain point, and at that point, they've reached a certain level of maturity, that's not the end of the development of these individual abilities.

One more question, difference between fluid intelligent and crystallized intelligence.

So fluid intelligence is the acquiring information as we go. So things that I can take on board. And so hopefully you were all a lot smarter than two hours ago, right? Because you've acquired loads of information in this lecture. And that is your fluid intelligence, Crystallized intelligence is things I already know, things that are embedded and that I can do habitually and I already have. So fluid, if you think of that as information that's coming through and passing as it goes, but it's like crystallizes, I've already got this and this is kind of my core knowledge there. They're both very much related and we're both really important that they tackle the more active component versus those abilities that we've already got. So, for example, language, we might learn new words and that could be adding to our IQ and things, but the crystallized knowledge is I know how to speak and interact with people. I have that baseline. Okay, because of time, I will move on from that. Again, I put some exam questions and things into or practice things into these slides. And next, we will be back to talk about memory. Thank you. Sorry about the cough today, but thank you very much for your attention. I'll see you next week.