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

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 (n129) 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.