Mirror-Touch Synaesthesia Is Not Associated with Heightened Empathy, and Can Occur with Autism.

Simon Baron-Cohen,Emma Robson,Carrie Allison,Meng-Chuan Lai,Hidenori Yamasue

doi:10.1371/journal.pone.0160543

Abstract

Research has linked Mirror-Touch (MT) synaesthesia with enhanced empathy. We test the largest sample of MT synaesthetes to date to examine two claims that have been previously made: that MT synaesthetes (1) have superior empathy; and (2) only ever experience their MT synaesthesia in response to viewing a person being touched. Given that autism has been suggested to involve deficits in cognitive empathy, we also test two predictions: that MT synaesthetes should (3) be less likely than general population individuals without MT synaesthesia to have an autism spectrum condition (ASC), if MT is characterized by superior empathy; and (4) have fewer autistic traits. We selected three groups: a pure MT synaesthesia group (N = 46), a pure grapheme-colour (GC) synaesthesia group (N = 36), and a typical control group without synaesthesia (N = 46). Participants took three measures of empathy and one measure of autistic traits. MT synaesthetes did not show enhanced empathy. In addition, 30% of all MT synaesthetes recruited into this study (N = 135) reported also having ASC, and MT synaesthetes showed higher autistic trait scores than controls. Finally, some MT experiences were reported in response to viewing objects being touched. Our findings dispute the views that MT synaesthesia is linked with enhanced empathy, is less likely to occur with ASC or elevated autistic traits, and is specific to seeing a person being touched.

Highlights

Synaesthesia occurs when stimulation in one sensory modality elicits an automatic response in another unstimulated perceptual modality [1]
The neural cross-wiring theory of synaesthesia proposes this arises through hyper-connectivity between sensory brain regions as a consequence of a genetic predisposition towards reduced axonal pruning that typically results in cell death in non-synaesthetes [12,13,14]
The present study aimed to test four important claims/predictions that have been made about MT synaesthetes: that (1) they have enhanced empathy; (2) that MT synaesthetes should be less likely than general population individuals without MT synaesthesia to have an autism spectrum condition (ASC); (3) MT synaesthetes should have fewer autistic traits; and (4) that MT synaesthetes should only feel the perception of touch in response to viewing a human being touched

Summary

Introduction

Synaesthesia occurs when stimulation in one sensory modality elicits an automatic response in another unstimulated perceptual modality [1]. The neural cross-wiring theory of synaesthesia proposes this arises through hyper-connectivity between sensory brain regions as a consequence of a genetic predisposition towards reduced axonal pruning that typically results in cell death in non-synaesthetes [12,13,14] The present study aimed to test four important claims/predictions that have been made about MT synaesthetes: that (1) they have enhanced empathy; (2) that MT synaesthetes should be less likely than general population individuals without MT synaesthesia to have an ASC; (3) MT synaesthetes should have fewer autistic traits; and (4) that MT synaesthetes should only feel the perception of touch in response to viewing a human being touched

Participants

Ethical Approval

Procedure

Results

Discussion