Would letters forming a word survive motion-induced blindness?

Abstract

Motion-induced blindness (MIB) refers to fluctuation in awareness of salient stimuli superimposed on a moving mask (Bonneh et al., 2001). MIB is known to be influenced by various perceptual grouping cues (Mitroff, Scholl, 2005). However, a question remains whether grouping of separate stimuli into a meaningful perceptual unit would be enough to prevent them from independent perceptual disappearance and reappearance. In other words, is there a word superiority effect (Cattell, 1886) for letter stimuli which are expected to be independently fluctuating in awareness due to MIB? In our experiment, we analyzed dynamics of MIB measured as disappearance frequency and duration for separate letter stimuli forming a word as compared to standard dot stimuli and meaningless letter strings. Four types of stimuli organized in a line above the fixation were presented to 21 subjects against the moving pattern in a counterbalanced block design: three yellow dots similar to used by Bonneh et al., three yellow empty circles (O's), three letters forming an easily readable Russian word (KOT, which means “a cat”), and three consonants, with two of them repeating the framing consonants of the word (KHT). No statistically significant differences either in the amount of disappearances of separate stimuli or in the total duration of disappearances between four conditions have been revealed. Thus, in spite of the recent neurophysiological evidence of early influences of WSE upon visual processes (Martin et al., 2006), letters against the moving mask seem to suffer from MIB before they can be grouped into a meaningful word.