Explaining the Colavita visual dominance effect.

The last couple of years have seen a resurgence of interest in the Colavita visual dominance effect. In the basic experimental paradigm, a random series of auditory, visual, and audiovisual stimuli are presented to participants who are instructed to make one response whenever they see a visual target and another response whenever they hear an auditory target. Many studies have now shown that participants sometimes fail to respond to auditory targets when they are presented at the same time as visual targets (i.e., on the bimodal trials), despite the fact that they have no problems in responding to the auditory and visual stimuli when they are presented individually. The existence of the Colavita visual dominance effect provides an intriguing contrast with the results of the many other recent studies showing the superiority of multisensory (over unisensory) information processing in humans. Various accounts have been put forward over the years in order to try and explain the effect, including the suggestion that it reflects nothing more than an underlying bias to attend to the visual modality. Here, the empirical literature on the Colavita visual dominance effect is reviewed and some of the key factors modulating the effect highlighted. The available research has now provided evidence against all previous accounts of the Colavita effect. A novel explanation of the Colavita effect is therefore put forward here, one that is based on the latest findings highlighting the asymmetrical effect that auditory and visual stimuli exert on people's responses to stimuli presented in the other modality.