Analysis of standard and non-standard visual word format in the two hemispheres

A dual-route model for the recognition of written words is hypothesised. The model postulates that the two cerebral hemispheres differ in their sensitivity to the visual format of verbal stimuli. Such stimuli may be 'standard', that is in Standard Visual Format (SVF), or 'non-standard', i.e. in non-standard Visual Format (NSVF). In the left hemisphere (LH), SVF words are routed directly to the lexicon, while NSVF words must go through an additional encoding phase prior to lexicon access. In the right hemisphere (RH) all words (SVF and NSVF) must proceed to an additional encoding phase prior to accessing the lexicon. Two lateralized lexical decision experiments are reported. In Section 2, angle of orientation was used to define SVF and NSVF. In Section 3, presentation of verbal stimuli was preceded by a cue indicating whether the coming lexical stimulus was in SVF or NSVF, while SVF was defined as in Section 2. The results showed that the difference in RT, favouring RVF stimulation was found for orientations up to 30°. Greater angles of presentation significantly reduced RVF superiority. The largest differences between responses to stimuli presented to the two visual fields was found when word stimuli were in SVF (up to 30°) and presented after a priming cue. The results are discussed in terms of the model, but alternative explanations are suggested.