Cogsci Lecture 5 - Attention

Attention

Why do we need attention? When is it not needed?

What is attention in terms of information processing?

what affects attention?

what happens when we attend to more than one thing?

what happens to unattended information?

What is meant by “attention as a filter”?

we have a limited amount of cognitive energy, and attention as a filter helps us divert our cognitive resources towards the most important thing. This is related to Donald Broadbent

What is the cocktail party effect? What is dichotic listening?

cpe is the ability to focus on a single conversation or stimulus while filtering out other distracting sounds (like if you are having a conversation with just one person at a cocktail party). dl is the technique Donald Broadbent developed when he wanted to understand how you focus on one audio source when the cocktail party effect is taking place. The listening technique he developed is one where you hear a different stimulus in each of your ears simultaneously and researchers can observe your attention based on what information you appear to take in and how quickly.

What is the Broadbent bottleneck model?

1) auditory message
2) enters sensory memory
3) goes through a filter (like attention)
4) this filter determines what information will go forwards into memory

in broadbent’s model — if you aren’t interested in it or attending to it, then it doesn’t get pushed forward to memory, but it is worth noting that the things you didn’t attend to you could still pick up on the low level linguistic features (for example if the volume was soft or loud, or if the voice was male or female)

What are the challenges to Broadbent’s model?

1) your own name captures your attention (implies that you know meaning/ it is processed despite the Broadbent claim that if you aren’t paying attention you only process low level features… but to respond to your name you need to be able to process more than just low level features)

2) the “Dear Aunt Jane” experiment: you tell a participant to only focus on things that are said into their left ear and ignore what happens in their right ear… but when they repeat what they hear they almost always say “Dear Aunt Jane” instead of just “Aunt Jane” or whatever was on only the left side. So they had no choice but to process auditory information even when told to ignore other things.

What is the Ann Treisman “Leaky Filter” model?

1) you get sensory messages

2) the attenuators filter processes low level policies
3) the unattended message is attenuated (not completely gone like Broadbent) — still goes to the dictionary unit
3.5) there is an attended message that all goes to something called:
4) the dictionary unit — the dictionary unit gets strong signals from words that you are paying attention to, but weak signals from words that you are not paying attention to

Key difference with Broadbent: the message that doesn’t pass the filter isn’t completely demolished it still gets put into the dictionary unit, it just has varying thresholds based on where your attention goes.

What is “Early” selection? “Late” selection?

we don’t know the mechanism in the brain well enough to know how selection of important vs unimportant auditory information actually happens in the brain/ with what mechanism

What is the processing capacity and perceptual load experiment?

What were the results of the experiment?

What does the differential effect of perceptual load on perceptual tasks that are highly demanding vs non-demanding tell us?

a) the experiment is one where they tell you what letter to focus on and then a circle appears with letters in it (on easy mode- its the one letter you are looking for and then the rest is just the letter o, on hard mode the circle is comprised of about 6 different letters), then they repeat the process but in addition to having letters, they have other distracting cartoons etc. on the screen

b) the results of the experiment show that without the additional visual noise (cartoons) the easy mode is easy and hard mode is hard, but with the cartoons, interestingly the level of difficulty for the already hard-mode task isn’t that much harder, while the level of difficult for the easy-mode task is significantly harder, and the change from the control (which is just the easy mode without the additional visual cartoon noise) was significantly larger than the change between hard mode with no cartoons and hard mode with cartoons.

c) interestingly it appears to show that when you are doing a task that you believe is easy, you are more easily distracted than when you are doing a task that you perceive as difficult. IE your categorization of a task as difficult leads to this inherent internal shift or implicit acknowledgement that this task will require more of your focus.

in terms of perceptual resources: the easy task doesn’t take much of your perceptual resources, but if you are doing a hard task you are already using more perceptual resources, so the additional noise added doesn’t really make much difference in general

What is the Stroop Effect?

its an experiment where you are shown a bunch of shapes that are a bunch of different colors, then you have a bunch of words you are told to ignore the word itself and only focus on the color but it takes longer because the words are the name of the wrong color (ie the word green is actually in the color blue).

it shows how powerful words are as distractors.

What is overt attention?

shifting attention from one place to another by moving the eyes — because we can see conscious attentional shifts by observing where the eyes are looking

What is a fixation? What is a Saccade?

the fixation is a point at which a participant of an attention study is looking at. Saccade is the movement of the eyes from one fixation to another.

What is covert attention?

attentnion that we can’t observe. Shifting attention while keeping the eyes still. This type of attention involves shifting attention “with the mind” as you might do when you are paying attention to something off to the side while still looking straight ahead.

What is Saliency in visual attention?

it refers to how much something in an image stands out. If it stands out the more salient it is and the more likely you are to divert your attention to it.

What are low level features of a stimulus?

what are high level features of a stimulus?

why is the distinction between these two things important to understand?

a) the physical properties of an image — its brightness, its contrast etc.

b) things we know about the stimulus that aren’t based on the stimulus itself but instead our prior knowledge

c) the distinction is important because if our attention/ information processing is based on the low-level features of something it is a bottom-up processing, but if it is based on the high-level features of something it is top-down processing

What is bottom-up information processing?

What is top down information processing?

How is top-down knowledge expressed in the guiding of attention, and which experiments show this?

a) bu info processing is when looking at sthing/ the image or stimulus itself is being processed and it is based on the most basic/ low-level properties of the image that our attention is directed one way or another

b) td info processing is based on prior knowledge or an idea of how a stimulus will look. you start by searching that image with top-down expectation. it involves information in addition to the foundation provided by bottom-up processing (processing that involves factors like a person’s knowledge of the environment, and expectations the person has for the perceptual situation)

c) prior knowledge affects the way that people scan images or scenes. You have prior schemas for example of what a kitchen looks like and what items should be in a kitchen, but if you see an item that is out of place you are more likely to fixate on it because it is not consistent with your prior schema. Eye tracking experiments demonstrate this.

What was Posner’s experiment?

What is Posner’s Precueing Paradigm?/ What do the results of Posner’s experiment tell us about covert visual attention?

a) the experiment is that participants are told to focus on a cross in the middle of a screen and not pay attention to the yellow arrows that appear, they are then told to clap the moment that they see the letter X which will appear either on the left or right side of the center cross. Then an arrow is shown pointing one way, followed by the X and the participants claps and this process is repeated where the arrow is sometimes pointing in the direction of where the X will appear, and sometimes pointing in the opposite direction

b) the pre-cueing paradigm is: you divert covert attention to location (your overt attention was on the cross, but the covert attention must have been on the arrows). Why? because when the arrows were a “valid cue” (pointing in the correct direction of the X), the response times were faster than when there was an invalid cue. Without some kind of covert visual attention, we would not have seen such results. IE it means that covert visual attention is real

What is object-based attention?/ What is the Egly experiment?

What do the results of the Egly experiment teach us about how we allocate attention spatially?

a) it shows you 2 objects (rectangles), there is a cue on a part of the screen that indicates which part of the object is about to be shaded in (A and B on two ends of one rectangle, and C on the end of an equivalently sized rectangle right next to it). Interestingly, when the cue is invalid (ie hints that A will be filled in when in fact instead it is C or B), people are quicker to divert their attention to B than they are to C even though both are equidistant from A, and they posit that this is because A and B are on the same object/ rectangle while C is on a different rectangle.

b) the results show us that we allocate our spatial attention to objects or according to objects and not just through locations in space. We know it is via objects because the experiment still holds true when you rotate the rectangles such that A and C are now on the same object

What is divided attention?

can we attend to more than one thing at once?

a) the idea that we can try to pay attention to two / multiple things at once.

b) yes if all of the “things” that you are trying to do at once are simple/ “automatic“ tasks from procedural memory like walking or chewing, but as tasks increase in their difficulty it is much harder to divert attention between multiple things

What is the Murphy & Greene Visual Divided Attention Experiment? (What modality is the task probing? What kinds of load are shown to affect it?)

What is the Murphy & Greene Cross-Modality Divided Attention Experiment? (What modality is the task probing? What kinds of load are shown to affect it?)

What is the Strayer & Johnston Divided attention experiment? (What modality is the task probing? What kinds of load are shown to affect it?)

What is common to all of these 3 experiments?

a) the divided attention while driving simulator — perform 2 tasks at the same time 1) decide if the car can pass between the two small cars (easy task) 2) decide if the car can pass between two big cars (hard task) — there was a pedestrian coming across in both simulations — the results showed that when the task was easier there was less visual perceptual load and so the participants were more likely to notice the pedestrian. When the task was harder however, they were less likely to see the pedestrian because the perceptual visual load was concentrated on the difficult task at hand.

b) the second Murphy experiment tested attention across Modalities (Ie testing both auditory and visual perception not just limited to one or the other). They had people in a driving simulation focus on the auditory stuff happening on a simulated car radio with both a difficult task and a hard task, then they had visual stimuli of elephants and other wild animals crossing the street, for the easier task they were more likely to notice the animals crossing than for the hard task because of the varying perceptual load between both tasks.

c) Strayer and Johnston studied talking on the phone while driving both holding the phone in your hand and then hands free. Interestingly, both diverted the driver’s attention in almost equal measure, so it wasn’t really about having a physical phone in your hand it was about the attentional load that comes with having to listen and speak to a device — interestingly the same results were not observed when there was a live passenger — IE drivers were more aware of the road when having a conversation with a passenger vs a hands free phone call

d) all of those 3 experiments test division of attention between “hard” and “easy” tasks and demonstrate to varying degrees that when a task is difficult/ requires more attention it is much harder to divide your attention to something else.

What is the Mack & Rock Inattentional blindness Visual Field experiment?

what does this experiment show about filtering out visual information?

a) its the experiment where participants are flashed a cross with a blue line and a green line — they are meant to figure out which line is longer in the brief second that they are shown the visual image — most people miss the fact that in addition to the cross there was also a small square on screen because their attention was so focused on the task at hand, they literally were blind to the other visual noise on the screen

b) when we attend to something — even if something else is super close to it in our visual field, the noise still might get filtered out and we won’t see it

What is inattentional blindness in everyday life? What are some examples?

1) students didn’t notice a clown unicycling on the way to class

2) people jogging missed a fight next to them

3) people didn’t notice money hanging from trees when they were walking in public

4) student cops didn’t notice a gun on a dashboard

this is blindness due to the fact that you aren’t paying attention to something and you are using your attention on something else

What is change blindness? What’s an example of change blindness?

This is blindness due to the fact that something subtle in the surrounding environment. For example: in class we were shown two similar images in rapid succession, when told to stare at the center you can’t really see the change or difference between the two images, but when you are allowed to move your attention around the image during the change, then you might be able to see it.

We were also shown a clip where the actors, decor, items etc. were switched out and changed right in front of us but we failed to notice because we were looking at the person who was speaking.

Another example was the Simon experiment where they had a receptionist at a front desk drop something in the middle of helping someone and when they bent down under the desk they had a new person pop up, but most people still didn’t notice that the receptionist had changed

What happens to stimuli that we don’t pay attention to/ are unattended? How do we process unattended stimuli?

What was the Li experiment? What type of stimuli was shown to be processed more easily outside the focus of attention?

a) The main task is that you are supposed to find the L among the pile of Ts presented, and the side tasks are 1) if you are looking at a nature scene in the bottom corner of your screen see if there was an animal or not, and 2) if you see a circle then tell me where the red or green is on a circle

b) the experiment found that the images of nature were easier to process in the periphery than the colors of a computer generated circle

What is meant by “Attention as a binding mechanism”?

What is a feature search? What is a conjunction search?

How are those tasks used to inform us about attention’s role in binding?

a) this is different from attention as a filter — attention is supposed to bind different elements together (for example a rolling red ball has multiple properties — red, rolling, round, etc. but you perceive it as one unified object even though your brain )

b) Conjunction vs feature search is relevant when observing patients with Balint’s syndrome. These patients have parietal damage. They are shown two images one has all vertical green lines and one horizontal green line that they are told to identify (they have no issue doing this). The second image is the same but they also add a bunch of red horizontal lines, and these patients can’t find the one green horizontal line anymore. These patients confuse properties in objects. They have trouble binding properties together. so they have an issue with “Conjunction Search” ie when multiple properties are shown in conjunction with each other, not feature search (when everything shares similar features except for one thing)

C) this informs attention as a binding thing to make something called “feature integration theory”: there are 4 stages:
1) there’s an object in space that your senses have picked up on
2) the pre-attentive stage is where your mind analyzes the sensory information into its features (color, shape, size, etc)
3) the focussed attention stage is where your brain actually pays attention and combines features
4) the final stage is conscious perception of the original object