Cross-Modal Dynamic Capture: Congruency Effects in the Perception of Motion Across Sensory Modalities Salvador Soto-Faraco Universitat de Barcelona Charles Spence University of Oxford Alan Kingstone University of British Columbia This study investigated multisensory interactions in the perception of auditory and visual motion. When auditory and visual apparent motion streams are presented concurrently in opposite directions, partici- pants often fail to discriminate the direction of motion of the auditory stream, whereas perception of the visual stream is unaffected by the direction of auditory motion (Experiment 1). This asymmetry persists even when the perceived quality of apparent motion is equated for the 2 modalities (Experiment 2). Subsequently, it was found that this visual modulation of auditory motion is caused by an illusory reversal in the perceived direction of sounds (Experiment 3). This “dynamic capture” effect occurs over and above ventriloquism among static events (Experiments 4 and 5), and it generalizes to continuous motion displays (Experiment 6). These data are discussed in light of related multisensory phenomena and their support for a “modality appropriateness” interpretation of multisensory integration in motion perception. The environment is perceived through an array of differentiated sensory channels (e.g., while standing near a railway track, one can see, hear, and feel a train as it passes by). However, people do not experience the world as a fragmentary collection of individual sensations corresponding to the information transduced by each separate sensory epithelia. Instead, the usual experience is that of unified and coherent perceptual events (e.g., a single train passing that produces different but related sensations to several senses concurrently). In fact, integrating information from different senses is essential to ensuring the maintenance of coordinated and veridical representations of the environment (e.g., Gilbert, 1941; Stein & Meredith, 1993). Moreover, there is growing agreement that a satisfactory account of multisensory processes will be inte- gral to any comprehensive theory of perception (e.g., Churchland, Ramachandran, & Sejnowski, 1994; Driver & Spence, 2000). A rapidly expanding body of research is now beginning to tackle the question of how information from the different senses is combined to form the multisensorily derived percepts that fill daily human life (e.g., see Driver & Spence, 2000; Stein & Meredith, 1993; Welch & Warren, 1986, for reviews). One particularly important class of multisensory interactions relates to biases in spatial perception. Spatial biases occur when the perceived loca- tion of an event in one sensory modality is modulated by the location of a concurrent event presented in another modality. The classic example of this is the ventriloquist illusion (Howard & Templeton, 1966), whereby a professional performer induces the impression that the sounds that he or she is producing (in a concealed manner) come from the agitated mouth of a puppet (see Connor, 2000, for a historical review of ventriloquism). In the laboratory, the ventriloquist illusion can be produced with simple stimuli, such as synchronized beeps and light flashes presented from spatially disparate locations, producing the illusory displace- ment of the sound source toward the location of the visual stimulus (e.g., Bertelson & Aschersleben, 1998; Urbantschitsch, 1880; see Bertelson & de Gelder, in press, for a review). The ventriloquist illusion, like other intersensory biases, depends at least in part on certain physical properties of the stimuli (these have been called “structural factors”), that convey the likelihood that two sources of information belong together, such as common onset (e.g., Soto- Faraco, Kingstone, & Spence, 2003; Welch, 1999). Indeed, one effective way to break down the illusion of ventriloquism is simply to introduce a temporal asynchrony between the auditory and visual events (e.g., Bertelson & Aschersleben, 1998; Caclin, Soto- Faraco, Kingstone, & Spence, 2002; Jack & Thurlow, 1973). An interesting characteristic of many intersensory biases is their asymmetric nature. For example, in the ventriloquism situation, visual events often modulate the perceived location of sounds, Salvador Soto-Faraco, Departament de Psicologia Ba `sica, Universitat de Barcelona, Barcelona, Spain; Charles Spence, Department of Psychology, University of Oxford, Oxford, England; Alan Kingstone, Department of Psychology, University of British Columbia, Vancouver, British Columbia, Canada. This research was supported by a Killam Trust postdoctoral fellowship to Salvador Soto-Faraco and by grants from the Michael Smith Foundation for Health Research, the Natural Sciences and Engineering Research Coun- cil of Canada, and the Human Frontier Science Program to Alan Kingstone. Correspondence concerning this article should be addressed to Salvador Soto-Faraco, Departament de Psicologia Ba `sica, Universitat de Barcelona, Passeig Vall d’Hebro ´n 171, 08035 Barcelona, Spain. E-mail: ssoto@ psico.psi.ub.es Journal of Experimental Psychology: Copyright 2004 by the American Psychological Association Human Perception and Performance 2004, Vol. 30, No. 2, 330 –345 0096-1523/04/$12.00 DOI: 10.1037/0096-1523.30.2.330 330