Social interoception: Perceiving events during cardiac afferent activity makes people more suggestible to other people's influence

Our judgements are often influenced by other people's views and opinions. Interoception also influences decision making, but little is known about its role in social influence and particularly, the extent to which other people may influence our decisions. Across two experiments, using different forms of social influence, participants judged the trustworthiness of faces presented either during the systolic phase of the cardiac cycle, when baroreceptors convey information from the heart to the brain, or during diastolic phase, when baroreceptors are quiescent. We quantified the extent to which participants changed their minds (as an index of social influence) following the social feedback, in order to compare two competing hypotheses. According to the ArousalConfidence Hypothesis, cardiac signals create a context of heightened bodily arousal that increases confidence in perceptual judgements. People should, therefore, be less subject to social influence during systole. By contrast, according to the Uncertainty-Conformity Hypothesis, cardiac signals increase neural noise and sensory attenuation, such that people should display greater effects of social influence during systole, as they then underweight private interoceptive signals in favour of the external social information. Across two studies that used different kind of social interactions, we found that participants changed their minds more when faces were presented at systole. Our results, therefore, support the Uncertainly-Conformity hypothesis and highlight how cardiac afferent signals contribute to shape our social decision-making in different types of social interactions.

Automated summary

Our judgments can be influenced by other people's opinions and interoception, but the role of interoception in social influence and the extent to which others can influence our decisions is not fully understood. In two experiments, participants were asked to judge the trustworthiness of faces presented during different phases of the cardiac cycle. We found that participants were more likely to change their minds when faces were presented during the systolic phase, supporting the hypothesis that cardiac signals increase sensory attenuation and neural noise, leading to greater susceptibility to social influence.