Thursday, October 28, 2010

Cna yuo raed tihs snetnece amd are yuo srupiriesd taht yuo can.

Jack Dikian
October 2010

Can yuo rmemeber to pruchsae tmoato suauce, can of baens, btuter, beard, and vegeatbels

There are (and have been) a number of models psychologists have adopted to describe or explain how we might recognize words (word recognition). Historically psychologists have moved from a theory where we use the overall shape of a word to one of using letters for word recognition.

Word shape or ‘Bouma shape”

The idea here is that we perceive words as complete patterns rather than a sequence of letter parts. Some claim that the information used to recognize a word is the pattern of ascending, descending, and neutral characters. This method was first described in the 1880’s by James Cattell, suggesting that we recognize word patterns as an overall image because we have seen these patterns on many occasions.

This model is supported by what is in cognitive psychology, the word superiority effect (the phenomenon that people are more accurate in recognizing a letter in the context of a word than they are when a letter is presented in isolation).

Some experimental support for the word shape model has been reported by Woodworth (1938) in his book Experimental Psychology.

Serial Letter Recognition

The method for word recognition is that words are read letter-by-letter sequentially from left to right. In essence, recognizing a word is equivalent to looking up a word in a dictionary. You start off by finding the first letter, than the second, and so on until you recognize the word. This model, however, can’t explain the word superiority effects.

Parallel Letter Recognition

Here, letters within a word are recognized simultaneously, and the letter information is used to recognize the words. This is a model that is currently accepted by most psychologists, with much of the evidence coming from eye movement work.

There are a number of [recognition] heuristics that are used to explain parallel letter recognition. An activation based parallel letter recognition model (an activation flow) requires stimulus letters to be processed simultaneously by first recognizing the features of the individual letters, such as horizontal lines, diagonal lines, curves, etc.

Activation flow from feature units towards word units and from word units to letter units may be used in a bottom-up and top-down process. In the bottom-up flow, stimulus letter features are sent to the “letter detector level”, where each of the letters in the stimulus word are recognized simultaneously. In this cascade system, the stimulus word is processed by first, the feature detectors, letter detectors, and finally word detectors.

Cattell, J. (1886). The time taken up by cerebral operations. Mind, 11, 277-282, 524-538.
Woodworth, R.S. (1938). Experimental psychology. New York; Holt.