The factors modulating the Colavita visual dominance effect
Poster Presentation

Camille Koppen
University of Oxford, Department of Experimental Psychology

     Abstract ID Number: 5
     Full text: Not available
     Last modified: February 26, 2007

Abstract
The Colavita visual dominance effect refers to the phenomenon whereby participants presented with auditory, visual, or audiovisual bimodal stimuli in a speeded response task sometimes fail to respond to the auditory component of the bimodal targets. We report a series of experiments designed to investigate the factors that modulate the Colavita visual dominance effect. Our results show that the magnitude of the Colavita effect is affected by the sensory modality (vision/audition) to which participants direct their exogenous (but not their endogenous) attention. The Colavita effect was also modulated by spatiotemporal factors: being larger when the auditory and visual stimuli were presented from the same position than from different positions, and larger when the visual stimulus preceded the auditory stimulus (as long as both stimuli were presented within the temporal window of audiovisual integration). Third, using signal detection theory, we demonstrated that auditory sensitivity decreases during the concurrent presentation of a visual stimulus while visual sensitivity is unaffected by auditory stimulation. We suggest that the Colavita effect decreases when the ‘unity of assumption’ is broken: i.e., it is reduced when participants perceive the auditory and visual stimuli as distinct events. The Colavita effect also results from prior entry and sensitivity shifts.