The second agent effect: Interpersonal predictive coding in people with schizophrenia

Interpersonal predictive coding (IPC) enables one to use the information conveyed by the communicative action of one agent to predict the response of another agent. IPC relies both on explicit reflective processes (processing of communicative intentions) and automatic reflexive processes (motor resonance). Predictive coding deficits may underlie positive symptoms in people with schizophrenia (SCZ), yet IPC has not been analyzed in SCZ. Thirty-nine SCZ and 22 controls (HC) completed a simultaneous masking detection task, during which they observed either communicative (Com) or individual (Ind) actions of agent A and had to report the presence of the agent B, who was shown in half of the trials. In line with previous findings, detection criterion was lowered after Com as compared to Ind, suggesting a higher tendency to report the presence of a second agent after observing agent A's communicative gestures . Surprisingly, this effect was found to a similar extent in both groups. Communicative criterion was linked to mentalizing abilities, but not to symptoms in SCZ. Finding that SCZ show similar IPC as HC adds to the previous evidence that reflexive processes may be relatively intact in patients. Furthermore, the level of reflective processes may be crucial for patients' social functioning.