Event-related potentials uncover the neurocognitive encoding and retrieval mechanisms of animacy effects in episodic memory

• Animate words were better recalled and recognized compared to inanimate words. • No evidence for P300 and slow wave effects indicating richer encoding of animates. • Animates elicited an attenuated N400, indexing facilitated semantic access. • Animates elicited an LPN, indexing controlled reconstruction of episodic details. • Animacy effect may be due to different semantic representations of the word types. Episodic memory performance is consistently higher for animate stimuli like humans or animals than for inanimate objects. To examine the mechanisms underlying this “animacy effect”, we recorded event-related potentials (ERPs) while healthy, young adults encoded and subsequently freely recalled (Experiment 1) or recognized (Experiment 2) words referring to animate and inanimate objects. In both experiments, we replicated the animacy effect. Further, in both experiments, animates elicited smaller N400-amplitudes than inanimates during encoding, suggesting that semantic access is facilitated for animate stimuli. No differences were found between stimulus types in any ERP markers thought to index elaborative encoding. In Experiment 2, the word types did not differ in the early mid-frontal and the left parietal old/new effects during recognition, indexing familiarity and bottom-up recollection, respectively. However, the late posterior negativity, presumably indexing controlled, effortful reconstruction of the study episode, was prominent for animates but absent for inanimates. Taken together, these results support a difference in the semantic representation between animates and inanimates, and more effortful recollection of a more complex episodic memory trace of animates during retrieval. Notably, these ERP patterns differ qualitatively from recent results on the survival processing effect, supporting a dissociation of the mechanisms behind the two effects.