Reconfiguration of parental defense by offspring presence in humans

Offspring survival depends on parental behavior, both for providing immediate protection from danger, and for transmitting information about what is dangerous and how best to avoid it. In rodents, the presence of offspring changes parental responses to danger, facilitating active threat coping over freezing. We investigated whether offspring presence reshapes human parental defense in a similar way, and whether parental defense in turn affects how effectively children learn vicariously about threats. We developed a virtual reality-based naturalistic paradigm where parents were able to display unconstrained defensive responses to a virtual attacker. Eighty-five parents participated with their own child, and forty with an unrelated child. All parents performed the task twice, once alone and once in the presence of the own/unrelated child. With their own child relative to alone, parents showed reduced freezing-like behavior, fought the attacker faster and more precisely, and stayed closer to their child. In turn, children sharing the environment with their parent showed enhanced physiological differentiation of sound cues predicting threat or safety. Moreover, increased proximity to the parent (but not to an unrelated adult) enhanced attack expectancy reported by the child afterwards. Altogether, our findings parallel and extend prior reports in rodents, and suggest that offspring presence induces an evolutionarily conserved reorganization of parental defense that facilitates both offspring protection and transmission of threat information.