The Selfish Brain: What Matters Is My Body, not Yours?

Abstract

Our behavioral response to our own crisis situations activates an automatic neural mechanism for protecting ourselves, while our response to others’ crisis situations is not always toward saving them. That is, this automatic neural mechanism is implemented in our brain essentially for protecting not others, but the self, based on a biological principle. In this regard, it can be said that we have a type of Selfish Brain mechanism, which works primarily for protecting the self. Here, we focused on bodily unstable situations, and investigated whether the Selfish Brain could be observed or not, by viewing these bodily unstable situations of the self and others, and comparing the neural and behavioral responses, based on a third-person perspective paradigm. We found significant brain activity specific to one’s own bodily crisis, but no significant activity in others’ crisis situations. These self-specific regions included the regions that would be activated during genuine unstable bodily states: the right parieto-insular vestibular cortex, inferior frontal junction, posterior insula, and parabrachial nucleus. These right-lateralized cortical and brainstem regions may mediate vestibular information processing for detection of vestibular anomalies, defensive motor responding (in which the necessary motor responses are automatically prepared/simulated to protect one’s own body), and sympathetic activity, as a form of alarm response during whole-body instability. Furthermore, there were no significant differences between the self and others in terms of subjective feelings. These findings suggest that the Selfish Brain mechanism is integral to our brains, and it works unconsciously and automatically to resolve one’s own crisis.