ATTENTION & PATTERN RECOGNITION:Word Superiority Effect

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Cognitive Psychology PSY 504

Lesson 20

ATTENTION & PATTERN RECOGNITION

Attention is required to combine features to perceive patterns.

Treisman & Gelade (1980) performed an experiment. They had the subjects try to detect a T in

an array of 30 I's and Y's. They reasoned that subjects could do this by simply looking for the

cross-bar feature of the T that distinguishes it from all I's and Y's. Subjects took about 800

milliseconds to make this decision. Triesman and Gelade also asked subjects to detect T in an

array of 30 I's and Z's. In this condition, they could not use just the vertical bar or just the

horizontal bar of the T; they could have to look for the conjunction of these features, performing

the feature combination required in pattern recognition. It took subjects more than 1200

milliseconds to make their decision. Thus, a condition requiring them to recognize the

conjunction of features took about 400 milliseconds longer than one in which perception of a

single feature was sufficient. Triesman and Gelade varied the size of the display they found that

subjects were much more affected by display size in the condition that required recognition of the

conjunction of features. Subjects showed little difference between the single feature and the

conjunction condition for displays containing fewer than five letters. Only with displays presenting

more distracters did subjects' attention become substantially overload. It might seem surprising

that attention is required to detect patterns of features that define common letters. We have

experience of automatically recognizing letters. For familiar letters the deficit in perception of

feature conjunctions only becomes apparent with large displays.

Attention is not just orientation.

Context & Pattern Recognition

Look at the top line you see a hen, a rabbit, after the rabbit there is dog and cat. After that there is

an animal even it is not clear. In bottom line you can see a picture of man, woman, child and girl.

We perceive the last picture as a picture of human. Even this picture is same like the above

picture. Because of the context we perceive things. Same picture when is included in animals

picture we perceive it as animal and when this is in human pictures we perceive it as human.

Top-Down Processing

Cognitive Psychology PSY 504

The general context provided by the words forces the appropriate interpretation. When context or

general world knowledge guides perception, we refer the processing as top- down processing,

because high-level general knowledge determines the interpretation of the low-level perceptual

units.

THE CAT

The middle letter can be seen as A or H.

Top Down Processing or contextual effects. It means surrounding has effect on our perception.

Word Superiority Effect

This phenomenon can be understood by the experiment of Reicher and Wheeler (1970).they

presented a brief presentation of either a letter (D) or a word (WORD). Immediately afterward

they were given a pair of alternatives and instructed to report which they had seen. If they had

been showed D, subjects might be presented with D or K as alternatives. If they had been shown

WORD, they might be given WORd, or WORK as alternatives.Subjects showed a letter alone or

in a word. Subjects were about 10% better in word condition. They more accurately discriminated

between D and K in the context of word than as letters alone. This phenomenon is called word

superiority effect (WSE).

Why WSE?

Rumelhart & Siple (1974) has provided one explanation for Why subjects are more accurate in

the word condition. Suppose subjects are able to identify the first three letters as WOR. Now

consider how many four-letters words are consistent with a WOR beginning WORK, WORD,

WORM, WORN, WORT

Suppose subjects only detect the bottom curve in the fourth letter. However, when the letter is

presented alone and subjects detect the curve, they will not know whether the letter was B, D, O,

or Q, since each of these letters is consistent with the curve feature. Thus, in WOR context

subjects need only detect one feature in order to perceive the fourth letter, but when the letter is

presented alone they must identify a number of features. Their analysis implies that Perception is

inferential. Like curve in D will help in recognition

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