PRELEXICAL SPATIAL REPRESENTATIONS

The Simon task was employed to establish the nature of the representat ion of printed words with which the mental lexicon is accessed. In the first five experiments, the subjects were required to discriminate ta rget letters in words or nonwords, presented vertically or horizontall y. The targets were located in the left (upper) part or the right (low er) part of the letter string. The response keys were placed either ho rizontally or vertically. In Experiments 1, 3, and 5 the subjects were asked to make a lexical decision and to respond only to targets withi n words or nonwords. In Experiments 2 and 4 the discriminative respons e was emitted regardless of the lexical status of the letter string. I n all experiments, a Simon effect was found that was congruent with th e mode-horizontal or vertical-of stimulus presentation. In Experiments 6 and 7, the letters were all presented at fixation. The results show ed the Simon effect in the horizontal dimension, as long as the subjec ts were given enough time to produce a visual image of the letter stri ng. It was concluded that the canonical representation of the word is produced only when the mode of stimulus input does not itself yield a spatial representation.