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Is synaesthesia one condition or many? A large‐scale analysis reveals subgroups
Author(s) -
Novich Scott,
Cheng Sherry,
Eagleman David M.
Publication year - 2011
Publication title -
journal of neuropsychology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 37
eISSN - 1748-6653
pISSN - 1748-6645
DOI - 10.1111/j.1748-6653.2011.02015.x
Subject(s) - psychology , feeling , perception , sensation , stimulus (psychology) , cognitive psychology , confirmatory factor analysis , exploratory factor analysis , sensation seeking , developmental psychology , social psychology , psychometrics , neuroscience , personality , economy , economics , service (business)
Synaesthesia is a broadly defined neural phenomenon in which stimulation of a sense or concept triggers a second perception not normally associated with the stimulus. For example, letters or numbers may trigger a colour experience, sounds may trigger a taste sensation, or tastes may trigger a feeling of touch. Dozens of forms of synaesthesia have been reported, but the relationship between the different forms has not been studied: is someone with a particular form of synaesthesia likely to possess other types? If so, which ones? As an inroad to illuminating underlying mechanisms, we here examine which different synaesthesia types tend to co‐occur. We analyzed reports of the forms of synaesthesia experienced by 19,133 participants who completed the Synaesthesia Battery (Eagleman, Kagan, Nelson, Sagaram, & Sarma, 2007), using correlation analysis, exploratory factor analysis (EFA), confirmatory factor analysis (CFA), and multidimensional scaling (MDS). Our analyses converged on the finding of five distinct groupings of synaesthesia forms. We label these coloured sequence synaesthesias (CSSs), coloured music synaesthesias, non‐visual sequela synaesthesias, spatial sequence synaesthesia (SSS), and coloured sensation synaesthesias. Collectively, our findings reveal that synaesthesia is an umbrella term that encompasses several distinct groups with independent probabilities of expression, and this may in turn suggest distinct underlying mechanisms and the possibility of different genetic bases.