Empathy as a driver of prosocial behaviour: highly conserved neurobehavioural mechanisms across species

Abstract

Empathy reflects the natural ability to perceive and be sensitive to the emotional states of others, coupled with a motivation to care for their well-being. It has evolved in the context of parental care for offspring, as well as within kinship bonds, to help facilitate group living. In this paper, we integrate the perspectives of evolution, animal behaviour, developmental psychology, and social and clinical neuroscience to elucidate our understanding of the proximate mechanisms underlying empathy. We focus, in particular, on processing of signals of distress and need, and their relation to prosocial behaviour. The ability to empathize, both in animals and humans, mediates prosocial behaviour when sensitivity to others' distress is paired with a drive towards their welfare. Disruption or atypical development of the neural circuits that process distress cues and integrate them with decision value leads to callous disregard for others, as is the case in psychopathy. The realization that basic forms of empathy exist in non-human animals is crucial for gaining new insights into the underlying neurobiological and genetic mechanisms of empathy, enabling translation towards therapeutic and pharmacological interventions.

Keywords: biological mechanisms; caring; development; empathy; evolution; prosocial behaviour.

Figure 1.

In humans, empathy is supported by a network of distributed, often recursively connected, interacting neural regions including the brainstem, amygdala, hypothalamus, striatum, insula, ACC and orbitofrontal cortex, as well as autonomic nervous system (parasympathetic and sympathetic branches which represent antagonist and coordinated regulation of internal states) and neuroendocrine processes implicated in social behaviours and emotional states. Thus, the experience of empathy and motivation to care for others emerge from the interaction of multiple areas in conjunction with the autonomic nervous system and the neuroendocrine system. (Online version in colour.)

Figure 2.

Empathically motivated prosocial behaviour in non-human animals begins with the perception of another conspecific's cues of need or distress, causing an orienting response and activation of attentional processes. The social context (e.g. kinship, relationship) influences the valence and intensity of the affective response. The observation of an affiliated other in distress causes a negative tension, aka stress. The other's distress is experienced as aversive to the observer, recruiting neural circuits related to aversion, including the brainstem, amygdala, ACC and insula, and a systemic stress response is initiated. In individuals with low resilience, or high stress reactivity, emotional distress can be overwhelming and lead to avoidance rather than approach behaviour. Signals of distress are a powerful call to action, experienced as a prosocial drive. In humans, perceiving or even imagining another in distress may also lead to empathic concern and caring, and comprises the basic motivating factors for behaviour directed at improving the well-being of the other. Activation of neural circuits involved in approach, caregiving and social decision-making processes are engaged, including the basal ganglia, hypothalamus and vmPFC. A high cost or lack of perceived ability to help successfully can reduce the motivation for helping. Successful helping is followed by the reduction of distress, and return to homeostasis in the victim, and by proxy in the helper. The social response from the victim is experienced as rewarding, and causes activation of reward circuits involving the striatum and NAcc that reinforce the behaviour and increase likelihood of its re-occurrence in the future.