Lecture 3- Feature Integration

Question 1

why do we need feature integration

Answer 1

to correctly combine object featuresand avoid perceptual errors

Question 2

what is feature integration also known as ?

Answer 2

Binding

Question 3

what do majority of studies use as a method of assesing perceptual feature integration?

Answer 3

Visual Search Tasks

Question 4

what is a target in a Visual Search Task

Answer 4

thing your searching for

Question 5

what is a distractor in a Visual Search Tasks

Answer 5

other items surrounding the target

Question 6

what is the aim of Visual Search Tasks

Answer 6

to assess the time taken to detect the target

Question 7

what variables of Visual Search Tasks can there be?

Answer 7

what the target looks like, number of distractors

Question 8

who provided evidence for Visual Search Tasks

Answer 8

treisman and Gelade 1980

Question 9

what is thefeature integration theory

Answer 9

claims that visual perception can be characterised by two functionally independent and sequential (one must happen for other to occur) stages

1st = pre attentive
- features are coded independently and in parallel using feature maps for colour, size shapes etc

2nd = attentive
uses cross dimensional processing
features from distinct feature maps are combined with each other via a window of attention which operates on a master map of locations

Question 10

describe the conjunctive (attentive) search stage of the feature integration theory

Answer 10

in order to combine individual features of an object- attention required and selection of that object occurs within a master map of locations

master map contains all locations in which a feature has been detected - with each location in the map having access to the multiple feature maps

when attention is focused on a particular location on the map - features currently in that position are attended to and stored as object files

if object is familiar -associations are made between the object and prior knowledge which results in identification of the object

Question 11

describe the relationships between the attentive and preattentive stages when using the visual search task

Answer 11

feature search (pre attentive)

• eg when many red T’s on a screen- with one green T - have to find green T
• differs by one feature- being its colour
• task can simply be solved by checking feature maps only to find what differs (colour)

Conjunctive search (attentive)

• target differs from distractors by 2 features ( you can only find the target based on the correct combination of features)
• integrate colour and shape
• 1 level up on master map of locations as recruits spatial attention

Question 12

From the observations by triesman and gelade what has been suggested abpout spaticial attention

Answer 12

• Sa is the glue that integrates features in visual perception

Question 13

what is another form of evidence for the roles of spatial attention in perceptual feature binding

Answer 13

illusory conjunctions

Question 14

what is predicted from Illusory conjunctions

Answer 14

• without focal attention- (without anythingto focus on) errors (illusory Conjunctions) should be observed
• in illusory conjunctions - report of features is correct (form checking featur maps - stage 1) but binding of features incorrect (something went wrong at second attentive stage )

Question 15

How can u measure Illusory conjunctions

Answer 15

Flanker Task - A behavioural task

Question 16

how doe sthe flanker task and illusory conjunctions relate

Answer 16

the occurance of illusory conjunctions is high in situations where spatial attention is diverted and when stimuli are presented very breifly ( so attention is unable to focus)
- demonstrated in flanker task

Question 17

what is the stimuli in Triesman and Schmidt 1982 task

Answer 17

4 shapes presented in a square- these shapes vary in size colour and format

flanked each side by 2 black numbers

Question 18

what is the task in Triesman and Schmidt 1982 study

Answer 18

1) you have to report the numbers then report the features of one of the four shapes
2) report the features of one of the shapes (focused attention condition)

Question 19

what are the findings of Triesman and Schmidt 1982 study

Answer 19

illusory conjunctions occur in the condition where flankers (numbers) have to be reported

interp=
- focussed attention was prevented since the arrayy was presented briefly (200ms) and attention was spread across stimuli and flanker letters

Question 20

what did Triesman and Schmidt 1982 alteration study allow

Answer 20

altered to allow focussed attention-

task= this time with same stimuli- relevant object location cued 150ms before the rest of the array

Question 21

what were the findings of Triesman and Schmidt 1982 altered study

Answer 21

when attention could be focussed- illusory conjunctions disappeared