On functional brain asymmetries in perceptual priming.

Brain asymmetries in implicit memory were studied using a perceptual identification priming paradigm. At the study phase, Subjects rated either the readability or the likeability of words. At the test phase, perceptual priming for these words was measured by presenting stimuli briefly either in the left or in the right visual hemifield. The typeface of the words was varied between the study and test. The orientation task manipulation at the study phase did not influence priming, although it had a powerful effect on a test of explicit memory. Priming effects were form-specific: words which were studied in the same typeface as they were tested were primed more strongly than words which were studied in a different typeface. No hemispheric asymmetries were observed in form-specific priming, but in general, priming was greater in the right hemifield/left hemisphere. These findings suggest that the hemispheres are equally effective in analysing and storing form-specific information at the early stages of word recognition process. Asymmetries favoring the left hemisphere may develop at a higher, more abstract level of presemantic visual word form processing.