Hemispheric asymmetry and theory of mind: Is there an association?

Abstract

Introduction. In autism and schizophrenia attenuated/atypical functional hemispheric asymmetry and theory of mind impairments have been reported, suggesting common underlying neuroscientific correlates. We here investigated whether impaired theory of mind performance is associated with attenuated/atypical hemispheric asymmetry. An association may explain the co-occurrence of both dysfunctions in psychiatric populations.

Methods. Healthy participants (n=129) performed a left hemisphere (lateralised lexical decision task) and right hemisphere (lateralised face decision task) dominant task as well as a visual cartoon task to assess theory of mind performance.

Results. Linear regression analyses revealed inconsistent associations between theory of mind performance and functional hemisphere asymmetry: enhanced theory of mind performance was only associated with (1) faster right hemisphere language processing, and (2) reduced right hemisphere dominance for face processing (men only).

Conclusions The majority of non-significant findings suggest that theory of mind and functional hemispheric asymmetry are unrelated. Instead of “overinterpreting” the two significant results, discrepancies in the previous literature relating to the problem of the theory of mind concept, the variety of tasks, and the lack of normative data are discussed. We also suggest how future studies could explore a possible link between hemispheric asymmetry and theory of mind.

Keywords:

• Autism
• Functional hemisphere dominance
• Schizophrenia
• Theory of mind

Notes

¹We performed a second ToM task, namely the hinting task (Corcoran, Mercer, & Frith, 1995), but do not report on its performance because participants made very few errors (ceiling performance). We consider it worth mentioning that performance in the VCT and hinting task did not correlate with each other (see also Fernyhoug, Jones, Whittle, Waterhouse, & Bentall, 2008).