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Interoception can contribute to social cognition by shaping emotional experience, the interpretation of others’ affect and the regulation of attention and action; it is not established as a universal prerequisite for understanding minds. Internal bodily signals are one source of information among visual, linguistic and contextual cues. A useful account must distinguish physiological state, detection of that state and interpretation of its significance.

Interoception includes processing signals related to the internal body. For social cognition, a faster heartbeat might contribute to experienced arousal, influence the significance of a threatening face or become evidence in an interpretation of one’s own discomfort during an interaction. The same change could accompany fear, effort or excitement. Bodily input therefore does not arrive with an unambiguous social label. Its contribution depends on context, expectations and the person’s ability to distinguish their own state from another’s.

Measurement is consequently central. Interoceptive accuracy is performance on an objective task; interoceptive sensibility concerns subjective reports; interoceptive awareness, in a more specific metacognitive framework, concerns how well confidence tracks actual performance. A primary comparison found these dimensions empirically dissociable rather than interchangeable. Someone who often attends to the body need not detect its signals accurately, and someone who performs accurately need not know when they are correct. A study connecting a questionnaire to empathy therefore cannot automatically be interpreted as connecting sensory accuracy to empathy.^[ref]

Neuroimaging provides a plausible substrate. During heartbeat-timing judgments, right anterior insular/opercular activity related to objective performance, alongside a wider set of responses. This links a region involved in representing bodily state to measured interoceptive behaviour. Other work found affect-related insular recruitment when participants experienced pain themselves and when a partner experienced it. These observations support a possible bridge between self-state representation and vicarious affect, but anatomical overlap does not prove that exactly the same neurons or computations implement both functions.^[ref][ref]

Manipulating when a social stimulus arrives offers a different test. A cardiac-phase experiment presented emotional faces at systole or diastole, using cardiac monitoring to time stimuli. Fearful faces were detected more easily and judged more intense at systole than diastole; associated imaging showed greater amygdala responses to fearful faces at systole. This shows that the bodily cycle can influence processing of an external affective cue even when the observer is not explicitly reasoning about their own heartbeat. It does not establish that consciously accurate heartbeat detection is necessary for the effect, or that cardiac phase explains every social judgment.^[ref]

Individual-difference evidence suggests another pathway. Alexithymia concerns identifying and describing one’s emotions, not having no emotions. In one study, empathy-related insula responses varied with alexithymia rather than autism diagnosis after adjustment. A separate psychophysical study associated alexithymia with interpreting facial expressions, while physical expression discrimination and identity judgments supplied important controls. Together they suggest that access to, or interpretation of, affective states may contribute to selected social-emotional tasks. They do not prove a single bodily-sensing deficit causes all these effects.^[ref][ref]

A direct interoceptive comparison also found that heartbeat-counting performance tracked alexithymia more clearly than autism across its tested groups. Its interpretation depends on the validity of the counting task. A common heartbeat counting score compares recorded counts $N_j>0$ and reported counts $C_j$ over $m$ intervals:A perfect heartbeat-counting score does not establish heartbeat detection: it only shows that reports matched recorded counts. Someone estimating from prior heart-rate knowledge can match the count without detecting individual beats. The score also depends mechanically on the denominator, so a relationship with actual heart rate needs interpretation. Empirical measurement analyses have exposed such problems; they qualify the inference from counting to perception, not the existence of bodily influences on cognition.^[ref][ref]

The statistical critique also needs qualification. A published reanalysis argued that several bivariate findings arise from analysing a ratio score and are less decisive than first claimed. This does not resolve every strategy or validity concern, and it does not invalidate the logical counterexample above. Mathematical dependence, sensory detection and behavioural usefulness should be tested as separate questions.^[ref]

A strong interoceptive account must therefore specify the intermediate mechanism. Bodily input may change experienced affect, which changes attention to another person; uncertainty about one’s own state may complicate separating self-generated distress from another’s needs; physiological regulation may help sustain a demanding interaction. These are different causal routes. Each requires measurements of its proposed intermediate steps, temporal ordering and controls for general anxiety, task comprehension and sensory or motor demands. Merely correlating two questionnaires cannot choose among them.

There are also clear limits to generalization. Cardiac detection does not measure every visceral modality, and evidence about recognizing emotional faces does not automatically explain representing a false belief. A shared insular signal is not a complete theory of interpersonal understanding. Good tests combine validated bodily tasks, objective physiology, confidence measures and independently defined social outcomes, ideally manipulating bodily input while testing competing explanations. By the examination date, converging studies supported a contribution to some affective aspects of social cognition; the claim that one interoceptive deficit explains all social difficulties was substantially stronger than the evidence.

The strongest explanation is a heterogeneous developmental account in which specific cognitive and sensory differences interact with co-occurring conditions and the social environment. No single deficit adequately explains all psychological difficulties experienced by autistic people. For particular emotional difficulties, alexithymia is a well-motivated candidate mechanism; for interpersonal difficulties, mismatched communication and exclusion are important competing or interacting causes. A useful explanation must say which outcome it explains and distinguish evidence from a broad label.

The outcome itself needs clarification. Differences in social communication, distress during unpredictable or sensory-demanding situations, difficulty identifying emotions and anxiety are not one psychological variable. An autistic person may show one without another, and outwardly similar avoidance can reflect different causes. Diagnostic criteria describe a pattern; they do not identify a single neural lesion, establish an absence of empathy or determine an individual’s quality of life. A theory should predict a specified process and explain variation within the autistic population as well as average differences from a comparison group.

A global theory-of-mind deficit is therefore insufficient. Mental-state reasoning can be difficult in some situations, and language, executive demands or spontaneous use can influence performance. Yet explicit task success and fluent conversation need not covary perfectly, while sensory overload and repetitive behaviour are not automatically consequences of failing a false-belief test. Calling every social misunderstanding mindblindness risks redescribing the outcome. The more precise question is which information the person represents, how it is accessed and whether the interaction supplies cues that both participants interpret similarly.

The broken-mirror hypothesis offers a neural mechanism but faces related specificity problems. One child study found preserved goal-imitation and action-representation measures despite differences in theory-of-mind performance. This challenges a universal failure of action matching as the cause of all autistic social difficulties. It does not prove every mirror-related response is typical; it shows why evidence about one imitation task or one activation contrast cannot stand for an entire diagnostic explanation. The developmental origin, current function and social consequences of a matching response require separate tests.^[ref]

Other single-process theories can contribute without becoming universal explanations. Differences in executive control may affect switching, planning or managing competing demands. Weak-central-coherence accounts emphasize local and contextual processing; social-motivation accounts emphasize orienting, reward and developmental experience. Predictive-processing accounts can formulate differences in expectations or the weight given to sensory evidence. Each needs independent measures and competing predictions. Observed withdrawal alone does not distinguish low social interest from anxiety, sensory strain or previous rejection, and a flexible account that explains any behaviour after the event is weak evidence for a mechanism.

For identifying emotions in oneself or others, alexithymia provides a more discriminating hypothesis. Across two psychophysical experiments, alexithymia related to difficulty interpreting emotional expressions, while controls separated expression interpretation from physical discrimination and identity judgments. An interoceptive study likewise associated its measured difficulty more clearly with alexithymia than autism. These results favour measuring a co-occurring dimension rather than treating emotional difficulty as a necessary feature of autism. They do not establish that every autistic person is alexithymic, or that alexithymia explains every communication or sensory difference.^[ref][ref]

This account has testable limits. Alexithymia questionnaires require insight into one’s own emotional abilities, and heartbeat counting can be influenced by beliefs and timing strategies. Anxiety, language and overlapping questionnaire content may create or obscure associations. Consequently, converging behavioural, physiological and longitudinal measures are needed before inferring a causal chain from interoception through emotion identification to social difficulty. A selective association is useful evidence against diagnostic essentialism, but it is not a complete causal theory of autism.

A relational explanation addresses another level. The double-empathy proposal treats mutual understanding across differing experiences as a two-way problem. It was initially a theoretical argument, not proof that all difficulties are socially imposed. Experimental story-transfer work subsequently found that mixed-neurotype chains lost information more readily than same-neurotype chains in the tested setting. This is evidence that communication success depends on partner composition. It supports investigating shared expectations and conventions, while leaving open effects of familiarity, recruitment and the particular task.^[ref][ref]

The wider environment can also contribute. In thin-slice studies, non-autistic observers formed less favourable first impressions of autistic speakers and expressed less willingness to interact; evaluating speech transcripts did not produce the same pattern as audiovisual presentation. Thus some barriers can arise from other people’s reactions to communication style rather than the substantive content conveyed. These controlled judgments do not establish the cause of every real-world relationship difficulty or later mental-health outcome. They nevertheless show why a theory confined to an autistic individual’s presumed deficit omits an experimentally demonstrated part of the interaction.^[ref]

The most plausible explanatory programme combines these levels without treating them as interchangeable. A sensory or cognitive difference may change an interaction; repeated misunderstanding can alter expectations and anxiety; co-occurring emotion-identification difficulties may complicate recognizing or communicating distress. Those pathways are hypotheses to test prospectively, including autistic people with varied language and support needs. Results from verbally fluent research volunteers cannot represent the whole population, and support needs must not be dismissed merely because interpersonal context matters.

The decisive criterion is explanatory specificity. For a facial-emotion task, an alexithymia-related interpretation account can outperform a global autism-deficit explanation. For a difficult conversation, partner mismatch and exclusion may add explanatory power beyond an individual task score. For other outcomes, sensory, developmental or co-occurring clinical factors may dominate. This evidence favours multiple interacting mechanisms and individually measured needs over either a universal inability to understand minds or a claim that the social environment explains everything. It motivates scientifically testable, outcome-specific explanations rather than conclusions about an individual based solely on diagnosis.