Multisensory Research 29 (2016) 29–48 brill.com/msr Crossmodal Correspondences: Four Challenges Ophelia Deroy 1,* and Charles Spence 2 1 Centre for the Study of the Senses, Institute of Philosophy, School of Advanced Study, University of London, Senate House, Malet Street, WC1E 7HU London, UK 2 Crossmodal Research Laboratory, Department of Experimental Psychology, Oxford University, UK Received 6 December 2014; accepted 6 March 2015 Abstract The renewed interest that has emerged around the topic of crossmodal correspondences in recent years has demonstrated that crossmodal matchings and mappings exist between the majority of sen- sory dimensions, and across all combinations of sensory modalities. This renewed interest also offers a rapidly-growing list of ways in which correspondences affect — or interact with — metaphorical understanding, feelings of ‘knowing’, behavioral tasks, learning, mental imagery, and perceptual ex- periences. Here we highlight why, more generally, crossmodal correspondences matter to theories of multisensory interactions. Keywords Crossmodal correspondences, sound symbolism, metaphors, multisensory interactions, unity assump- tion 1. Introduction For three decades or so, multisensory research has made a great deal of progress, and yet, until the last few years, has really hardly touched on the topic of crossmodal correspondences. Looking back over the field, discussion of the correspondences is notable by its absence from most seminal reviews of the field. For example, neither Welch and Warren’s (1986) influential review of human psychophysics, nor Stein and Meredith’s classic (1993) book on the neurophysiological underpinnings of multisensory integration mention the correspondences at all. Discussion of the correspondences is also largely ab- sent from Calvert et al.’s (2004) Handbook of Multisensory Processing, except * To whom correspondence should be addressed. E-mail: ophelia.deroy@sas.ac.uk  Koninklijke Brill NV, Leiden, 2015 DOI:10.1163/22134808-00002488