Cognitive Psychology Exam 2

CAT and THE objection recognition example found

Identical stimuli or features can be recognized as different objects/representations

Example - the middle figure is seen as an H when in THE, but is read as an A when in CAT. The same figure is being interpreted differently in a way possibly influenced by familiarity, context, etc

Chair views object recognition example found

Different features/input can be recognized as the same object

Example - The chair is shown from 3 views that produce very different representations, but they are all three recognized as the same object.

Why is object recognition a challenging information processing task?

Due to the challenge presented since the system must make it so that

The same features can be recognized as different objects

Different features can be recognized as the same object

The problem of invariance

Object invariance references the ability to recognize objects regardless of point of view

Any successful theory of object recognition must be able to explain how object invariance is achieved.

Ventral Processing Stream

Begins at V1 and projects to the temporal lobe

This stream deals with object recognition

Dorsal Processing Stream

Begins at V1 and projects into the parietal area of the brain

This stream deals with location recognition

Agnosia is defined as 

impaired object recognition resulting from ventral stream damage.

Apperceptive (integrative, visual) Agnosia

patients get features of object but cannot put them together properly in recognizable representation. Thus they cannot recognize/identify everyday objects.

Suggests that objects are represented as combinations of basic features

Associative Agnosia

patients minds can represent well-formed objects, but cannot connect those representations with their meaning (semantics). Malfunctioning part-based 

Suggests recognition requires associating perceptual representations with stored representations

Prosopagnosia (Face-blindness)

an example of category-specific loss; an inability to recognize faces even though other objects can be recognized. Can’t recognize face of family from a stranger. Sometimes cannot even recognize their own face.

Recognition consists of multiple separable systems which may function differently

How are words represented in a simple feature network

They are represented as orientations of simple lines.

i.e. a bottom curve as seen on a C, or a vertical line such as in L

The are then turned to letter detectors. The word only forms from frequency

Frequency

Detectors that are partially activated due to being activated more often

Priming

Detectors that are partially activated because they have been activated recently

How do frequency and priming effects occur within a simple feature network?

With either of these, the detectors are already partially activated. They therefore require less additional activation to reach threshold and send activation to other detectors. As a result, words and their features that are more frequent or primed are recognized more easily

Explain how adding a bigram layer helps with recognition when the input is poor but can also cause recognition errors

The Bigram detectors are an added layer to the feature networks which represent grouped parts that frequently appear. This helps us to more easily recognize words with groupings (such as TH). If one letter is missing, bigrams represent the common pairs that might complete to missing letter.

Bigrams reflect the rules of the language; no TJ bigram detector in an English speakers brain...but would be in a German or Swedish speaker’s brain.

Thus why nonsense spelling which conforms to language rules such as CQRN is more likely to be mistaken as CORN due to bigrams. The system will activate CORN if it sees CQRN as an input-error (misperception)

What is the problem of invariance with regard to object recognition?

Object invariance refers to the ability to recognize objects regardless of point of view. Any successful object recognition must explain how object invariance is achieved

The problem of object invariance can be appreciated by what is wrong with template models of object recognition. Essentially asking How does the system achieve object invariance.

EX. Template theory—we would need multiple stored templates for every object and its angles. Thus simple template theories do not solve invariance. These theories are also poor at explaining human recognition

Explain the Recognition by Components (RBC) theory of object recognition. How does it handle the problem of invariance? 

Recognition by Components (RBC) theory of Object Recognition – Object representations are built out of representations of component parts (structural description model)

The individual parts (36 total) are called Geons defined by viewpoint-invariant properties, and objects are a set of geons. The structural description is a list of parts and their spatial relations.

If parts are recognizable regardless of viewpoint, and objects are defined by a set of parts, then objects can be recognized regardless of viewpoint

Explain the Recognition by Multiple Views theory of object recognition.  How does it handle the problem of invariance differently from RBC?

Recognition by multiple views theory of object recognition - composite representations are established by storing many images of an object from many different points of view and condition. These are essentially elaborated template models.

Invariance is solved by having representations across many views and exemplars against which to compare the input.

Explain the difference between part-based and holistic processing.  How does the Thatcher Effect suggest that face perception relies on holistic processing? 

Part based – structurally based, which is made up of simple parts, doesn’t really apply when most people have 2 eyes, nose, and a mouth

Holistic Processing – recognition depends more on the representation of relations between parts or configurations than on parts ‘the whole is greater than the sum of the parts’

Thatcher Effect – when  viewing a face in normal orientation, they are processed as faces (alterations made seem obviously wrong). However when viewed upside down we cannot identify the difference between them, as they are processed by the normal object recognition, not our face processing. Veggie painting- the ‘face’ is only detected when at the orientation of normal faces

When upside down it is part-based processing as it is not in the usual orientation

When right side up it is holistic processing, as you see the face all together and it looks wrong.

 What is the Inversion Effect? Describe an experiment (logic, results, and conclusion) using the inversion effect that supports the hypothesis that recognizing faces is different from other kinds of object recognition because it relies more on holistic processing.

The Inversion Effect – face recognition is impaired more by inversion than non-face object recognition is impaired. Upside down faces don’t engage the holistic face-processing system

 If we have a marked difference in recognition being affected (still errors, but many more in one case), there is then some evidence that faces are processed differently than objects.

What are the key characteristics of attention that are captured in William James’ quote that starts out “Everyone knows what attention is…”?

-        One out of several objects (selective)

-        Taking possession (active process)

-        Clear and vivid detail (causes relative enhancement)

If human information processing were not limited capacity, then attention would be unnecessary.  Explain why this is true.  Include an explanation of what “limited capacity information processing” means.

Limited capacity information processing – we cannot process multiple things with the same amount of efficiency as when we process a single thing

If our information processing was not limited, we would not need attention on a single thing in order to better and more efficiently understand it when dealing with too much input. Essentially we then wouldn’t need to filter information

Explain the visual search experiments with red/green horizontal bars (feature search and conjunction search). 

The Task - Find the green, vertical rectangle.

Difference in experiments -  In the first, all the other rectangles are red (vertical or otherwise)

In the second, the rectangles were half of each color, so all other green rectangles were horizontal and all other red rectangles were vertical

Explain how the conclusion that representing individual features is unlimited capacity, but representing conjunctions of features is limited capacity follows from the results of the two experiments.

individual features is unlimited - when the only feature different was green, it was an very quick reaction time to find the out-of-place object, processing the difference

Conjunction of features is limited - when the features were combined the reaction time grew as the number of objects did, since the observer needed to shift attention by each item, taking much longer than with a varying number of objects but only one unique feature.

Change Blindness

The failure to notice (sometimes large) changes if you happen to not be attending to whatever changes as it changes. (cooler on boat)

Cannot be overcome by virtue of knowing it exists

Inattentional Blindness

The failure to notice things in your environment that you aren’t expecting and therefore are not attending…even though there are easy to notice when attended. (gorilla in video)

Cannot be overcome solely by virtue of knowing it exists

What is the attentional blink?  Describe how it is measured experimentally. 

Attentional blink – a period of time following the engagement of attention during which we are effectively blind to other things and fail to register new information. Even though our eyes are open

Identical stimuli but different task demands

Made people look at a cross and tell which line was longer. At the same time flashed a simple shape on the screen. When not aware of it, most didn’t notice and only 50% could say what it was correctly. When aware the number of people who got it correct drastically rises

Control task importance - If T1 is presented, but you don't have to process it, then you should not miss T2.

From discussion: When you select an item you temporarily block any other info while processing the first item, before recovering enough to process the second item

Describe the ERP evidence that is often interpreted as evidence of early selection? Discuss the difference between “early” in time versus functionally early (i.e., in the type of processing that has occurred).  Does the ERP evidence concern time or function?

Evidence found that attended and unattended stimuli are processed differently, speed was very early after stimulus. However this does not actually provide evidence for early/late selection, as they are related to where in the processing stream selection occurs. Not actually related to timing/speed

Describe the Stroop effect and why it suggests that selection is late?

Stroop effect – when required to name the color of a word stimuli. When the word stimuli correspond to a color name that is different from the actual color that the word is typed in, you cannot block the word meaning. Stroop suggested that reading is automatic.

Evidence of late selection as the meaning of the word was interfering, meaning that the meaning of the word was still being processed, so the early filter couldn’t be interfering

Explain how the cocktail effect is similar to the Stroop effect

Cocktail party effect – If you hear your name in the unattended ear with dichotic listening/noisy environment, you will notice.

It is similar to Stroop in that it supports late selection, and contradicts early selection with meaning poking through. Later suggested also that the filters are not all-or-nothing, and so important things with low thresholds, such as your name, can still be recognized

Describe the logic and design of the spatial-cueing experiment. What is the evidence that there are both costs and benefits to selective processing.

Using arrows to indicate where something pertinent is likely to appear. Some trials had no arrows, some correct, and some incorrect.

Found that valid cues had smallest response time, but invalid cues had the longest reaction time.

Benefit of speed of being told where it would be, but cost of speed if that cue is incorrect.

Describe the difference between bottom-up and top-down attentional control.

Bottom-up attentional control – controlled by stimulus – attention guided by capture. Stimulus has to be unique in a single positive (additive not subtractive) aspect to surroundings to capture attention.

Top-down attentional control – controlled by observer – attention guided by goals

What is unilateral neglect (a.k.a hemispatial neglect)?  What type of brain damage is it associated with?

Unilateral neglect - a form of dysfunction with attentional guidance that occurs following unilateral damage to the parietal cortex/posterior parietal lobe.

Presents as people only being able to attend to the one side of space. Does not affect memory though.  They can see the lines on the left side with no problems, when their attention is drawn to them. They just fail to shift their attention to them on their own. (The clock in Hannibal is an example)

Describe two experiments—one using response time as a measure and one using activity in FFA versus PPA—showing that selection can be object-based (i.e., we select objects) as contrasted with space-based (i.e., we select regions of space).  

The invalid cuing with same difference in space, but only one in the same object. speed was faster for same distance in the same object, than in the same distance but a different object. Because space was not a factor, only object could have affected results. The cue highlighted the entire object for selection not just one end, and that is why the response was quicker.

House and faces alternating flashing in the same space. Stimuli don’t change, but activity changes when which stimulus is attended changes. There is more activity in the FFA when faces focused on. More activity in the PPA when houses focused on.

What is divided attention

Divided attention is when we try to distribute our focus among multiple things

Some tasks interfere with each other more than other tasks…suggesting that there are specific resources in use

Explain two sources of divided attention: task/domain specific versus domain general. Reference the concept of executive control in your answer.

Task/Domain specific - Two tasks can interfere with each other because they both require access to some specific process (domain specific) ie. both visual or need motor response

Domain general - Two tasks can interfere with each other because they both require access to a general control mechanism (domain general) ie. Cognitive control

Executive Control - refers to processes that determine how specific resources are allocated across multiple tasks

Describe the experiment showing that driving and talking on the phone impairs driving performance more than driving and talking to someone who is in the car.  What is an explanation for that difference?

It is safer to take to someone in the car because talking to someone who isn’t present causes problems.

Passengers can react to the same events as the driver. Be quiet when certain events need more attention, or even speak up when there seems to be something the driver might not notice.

Drivers talking to someone on the phone often visualize the person on the other end (like their facial expressions in reaction). This visualization takes a lot more visual cognitive processing than it should if you are also driving and predicting the movements of other cars.

Describe the example of perseveration in a task that we saw in the video with the child being asked to switch from playing the “shape game” to playing the “color game”.  That is an example of undeveloped executive control.  Brain damage to what part of the brain can cause similar behavior in adults?  

The phenomenon in which a person continues doing a task even though they are instructed to switch, and the first task is no longer relevant to the second task. Damage to ability in shifting attention is in the frontal lobe and executive control. It is a failure of executive function.

Brain damage in the frontal lobe can result in the brain can cause perseveration in adults