The word superiority effect: modulation by language familiarity, handwriting, and inversion

Literate humans are expert in reading text. On proposed reflection of this expertise is a whole-word influence on the identification of letters. In the present study, we investigate the word superiority effect, and how language familiarity, orientation and script regularity modulate this effect. We recruited two groups of 20 subjects, one fluent in Farsi and one in Punjabi. Members of neither group were familiar with the other group's language. We presented four-letter words or pseudowords briefly, following which subjects had to indicate which of two letters had been part of the four-letter stimulus. We present blocks with Farsi and Punjabi separately, as well as upright or inverted stimuli separately, to measure the impact of both language familiarity as well as experience with orientation, given that most of a subject's exposure to text is with upright words. Within blocks we varied whether stimuli were shown in a computer font or in handwriting. We found a significant word superiority effect for the familiar language but none for the unfamiliar language. For the familiar language, the word superiority effect was greater for upright stimuli, but still present with inverted stimuli. The word superiority effect was of similar magnitude for font and handwritten text. We conclude that the whole-word influences that generate the word superiority effect arise solely through experience with a language and depend strongly on the learned orientation of text, but are not modulated by script regularity.