Directional letter-by-letter analysis and the word-superiority effect.

Abstract

Manipulations were introduced in three experiments to produce letter-by-letter analysis of orthographic (CVC) and nonorthographic (CCV or VCC) trigrams. Letters in the trigrams were presented in a different form (normal orientation and order, normal orientation but reversed order, reversed orientation but normal order, or reversed orientation and order) to each of four groups in the first experiment, and in each of the two normal orientation forms to different groups in the second experiment. Subjects both detected the presence or absence of a target letter and classified each trigram as a word or nonword. Additional changes were introduced in the third experiment to ensure that letters were being analyzed in the desired order. Performance was consistently better on orthographic trigrams, but only if the letters were oriented normally. This word-superiority effect (WSE) was related to feature testing that may be carried out letter by letter, with more efficient testing on words. Failiar orientation of letter features seems to be necessary; otherwise, testing becomes so difficult that there is no WSE. However, testing apparently is not finished on a given letter before it is begun on the next.