Increased Heartbeat Interoception Is Predicted by Autism Spectrum Traits in the Typical Population

Background: The term interoception describes the sensitivity to or awareness of internal bodily processes such as arising from the heart or visceral organs. Interoceptive awareness has been proposed as fundamental building block of self-awareness, emotions, decision making and empathy. Decreased interoception has been associated with alexithymia, which is characterized by difficulties in processing one's own emotions. Although impairments in, for example, self-referential and affective processing as well as empathy have been described for Autism Spectrum Disorders (ASD), the link to a fundamental deficit in interoception has not been made yet.

Objectives: We sought to investigate the relationship between interoceptive awareness and autistic traits, empathetic concern, perspective taking, and alexithymia in the typical population.

Methods: A classical heartbeat counting task was used to measure cardiac awareness as one type of interoception in 37 typically developed adults. Participants were asked to introspect and count their own heartbeat. The extent to which typical adults displayed autistic traits was measured using the autism-spectrum quotient (AQ). Moreover, empathetic concern and perspective taking were assessed with the Interpersonal Reactivity Index (IRI) and Alexithymia with the Toronto Alexithymia Scale (TAS-20).

Results: Heartbeat counting was positively correlated with the overall extent of autistic traits on the AQ. That is, the more accurate the participants' ability to count their own heartbeat, the more autistic traits they reported. There was no other correlation with cardiac awareness but perspective taking correlated negatively with the "communication" subscale of the AQ (i.e., self-reported use of language in a social context). In addition, difficulties describing feelings on the TAS correlated positively with "attention to detail " and "social skills" subscales of the AQ as well as with empathetic concern on the IRI.  

Conclusions: In contrast to previous assumptions, higher autistic traits are not associated with low interoceptive sensitivity but the opposite: typical adults with high AQ scores showed higher cardiac awareness. Instead of a deficit, higher egocentrism in ASD or typically developed adults with high AQ scores could represent an advantage for interoception. The present result contributes to the present discussion whether the self in ASD is best characterized as absent or as all too present.