Autobiographical memory reactivation in empathy

Empathy relies on the ability to mirror and to explicitly infer others9 inner states. Studies on healthy populations show consistent evidence supporting the idea that our memories play a role in empathy when building a representation of others9 inner states (Buckner & Carroll, 2007; Spreng & Grady, 2009; Spreng, Mar, & Kim, 2009). However, direct evidence of a reactivation of autobiographical memories (AM) when it comes to empathizing with others9 inner states is yet to be shown. To address this question, we conducted two experiments where we recorded electrophysiological (Exp 1) and hemodynamic activity (Exp2) from two independent samples of participants. In Exp 1, EEG was recorded from 28 participants who performed a classic empathy task, i.e. a pain decision task in which targets for empathy were depicted in painful scenes for which participants either did or did not have an AM, followed by a task that explicitly required memory retrieval of the AM and non-AM scenes. The retrieval task acted as a ‘localizer’ to extract the neural fingerprints of AM and non-AM scenes, which could then be used to probe data from the empathy task. A state-of-the-art EEG pattern classifier was trained and tested across tasks and showed evidence for AM reactivation when participants were preparing their judgement in the empathy task. Participants self-reported higher empathy for people depicted in situations they had experienced themselves (for which they would have an AM) as compared to situations they had not experienced. This behavioral result was replicated in a second fMRI Experiment, where hemodynamic responses were measured from an independent sample of 28 participants. Furthermore, fMRI results showed activation in the brain networks that have been extensively shown in previous studies to underlie both AM retrieval and empathy (Amodio & Frith, 2006; Bernhardt & Singer, 2012a; Buckner & Carroll, 2007; Frith & Frith, 2003; Spreng & Grady, 2009; Spreng et al., 2009; Zaki & Ochsner, 2012). Together, our study reports behavioral, electrophysiological and fMRI evidence that robustly supports the involvement of autobiographical memory reactivation in empathy.