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Philipp Kanske and collaborators. NeuroImage 122:6–19. Primary behavioural validation and neuroimaging; emotionality and mental-state reasoning manipulated independently.

DOI: doi.org/10.1016/j.neuroimage.2015.07.082

Geoffrey Bird and collaborators. Brain 133:1515–1525. Primary neuroimaging study with alexithymia assessed in both diagnostic groups.

DOI: doi.org/10.1093/brain/awq060

A researcher who coauthored neuroimaging studies separating alexithymia from autism in responses to another person’s pain. Measuring both characteristics helped distinguish a diagnostic-group difference from a correlated individual trait.^[ref]

Hugo D. Critchley and collaborators. Nature Neuroscience 7:189–195. Primary heartbeat-timing task and functional neuroimaging.

DOI: doi.org/10.1038/nn1176

Neuroimaging measures structural or functional properties of the nervous system. Different methods record different physical signals, so anatomical images and activity-sensitive measurements support different inferences.

For example, electroencephalography records electrical potential differences, while many functional vascular measurements depend on neurovascular coupling. Spatial overlap in an image is not by itself proof that one location implements a complete psychological process.

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.

Philipp Kanske studies social-affective and social-cognitive processes. His EmpaToM study independently varied emotional content and the need to infer a speaker’s mental state, combining behavioral measures with neuroimaging. The design helps separate empathy from theory of mind rather than assuming that a response to an emotional story measures both. ^[ref]

Researcher in neuroimaging and coauthor of work examining false positives in clustered functional magnetic resonance imaging results. The study revisited assumptions used to assign significance to spatial patterns, illustrating why analysis software and its statistical model must be evaluated together.^[ref]