The heart knows you are wrong: Heart rate modulations associated with perceptual errors

Subjective experience is rich, although it can be inaccurate. When tasks require the integration of features, they can be erroneously integrated, creating illusory perceptions. Some studies have explored the brain responses associated with subjective perception and correct/incorrect feature integration although the role of the peripheral nervous system has largely been neglected in this field. The main goal of the present study was to explore whether the heart rate is modulated by the perceptual process of feature integration. A color-shape discrimination task, titrated to produce 70 % correct (hits) and 30 % incorrect (illusions) responses, was used. Targets were preceded by a tone in 50 % of the trials to manipulate phasic alerting. Moreover, the role of top-down expectancies in feature integration was explored by introducing an unexpected attribute at the end of the experiment. Behavioral results indicated that phasic alertness did not influence feature integration; however, responses were faster when an alerting signal was present, compared to when it was absent. Moreover, correct feature integration (hits) elicited faster responses than incorrect integrations (illusions). Heart rate was modulated by feature integration, resulting in an enhanced deceleration pattern for illusions compared to hits. Participants who were aware or unaware of expectancy manipulation exhibited opposite heart rate patterns, possibly reflecting differences in preparatory strategies and internal error monitoring. These findings demonstrate that the peripheral nervous system differentially responds to distinct visual experiences, highlighting the need to consider peripheral physiological measures in perception studies.