Figure 1.

Key factors influencing bystander intervention. Affective empathy is a process in which humans directly experience the emotional state of another. Key brain areas implicated in affective empathy include the amygdala, insula, anterior cingulate cortex, and frontoparietal mirror neuron system (superior temporal sulcus, inferior parietal lobe, and the ventral premotor cortex). Cognitive empathy is the process of identifying with another person’s perspective and is thought to involve the medial prefrontal cortex, orbitofrontal cortex, dorsolateral prefrontal cortex, temporoparietal junction, superior temporal sulcus, and temporal pole (5,6). Cognitive empathy appears to be most important for bystander intervention (6,7). This process is influenced by individual, group, and contextual factors. At the individual level, witnesses are more likely to offer aid when they are in a positive emotional state, have watched other people model helping behavior, and believe themselves competent to assist (8,9). Identification with the victim also leads to more helping behaviors [and appears to directly relate to the degree of cognitive empathy (10)]. Group dynamics that increase the probability of intervention include when there are fewer people present, when the potential bystander is among friends (believed to be secondary to less fear of negative social appraisal), and when there is good communication between bystanders. Situational factors that increase intervention include a high degree of emergency and clear signals of victims’ distress. The setting of the emergency also plays a role. Individuals are more likely to intervene in places where they feel comfortable and where it is perceived to be safe (both physically and emotionally). Together, these social factors modulate intervention through the cognitive and affective empathy circuits described above (7).