A comparison of upper vs. lower and right vs. left visual fields using lexical decision

A series of experiments using the lexical decision task was conducted in or der to investigate the functional differences between the upper and lower v isual fields (UVF, LoVF) in word recognition. Word-nonword discrimination w as swifter and more accurate for word stimuli presented in the UVF. Changin g the eccentricity did not affect the UVF advantage over the LoVF. UVF supe riority over LoVF was found to be equivalent for both right and left visual hemifield (RVF, LVF). In general, presenting related word primes enhanced all visual field differences in a similar manner (UVF over LoVF and RVF ove r LVF). However, primes consisting of semantically constraining sentences e nhanced the RVF advantage over the LVF, but did not affect the UVF and LoVF differentially. The argument is made that UVF superiority cannot be due to perceptual or attentional differences alone, but must also reflect top-dow n information flow.