Theory of mind development can withstand compromised episodic memory development.

As humans, we are consciously aware of unobservable mental states, including our own during episodic memory and other people's by having a "theory of mind" (ToM). Episodic memory and ToM are closely related: they share a neural substrate and emerge close in time in ontogenetic development. This relationship is central to prominent child development and cognitive neuroscience theories of ToM, but its causal nature has not been tested empirically. The current study examined whether normal episodic memory development is necessary for normal ToM development. To investigate this, we tested H.C., a young woman with impaired episodic memory development due to early hippocampal damage, on a wide range of ToM measures. H.C.'s performance was indistinguishable from that of controls on all tests of ToM suggesting that, contrary to theoretical claims in the literature, normal episodic memory development and hippocampal function are not essential for the development of ToM.