Episodic memory processes mediated by the medial temporal lobes contribute to open-ended problem solving

The present study investigated the contribution of episodic memory processes mediated by the medial temporal lobes to solving open-ended problems: problems for which standard solutions or set procedures for arriving at solutions do not exist. Patients with unilateral temporal lobe epilepsy and excisions (TLE), older adults and control participants were asked to describe detailed solutions to various open-ended, social scenarios. TLE patients and older adults, both having deficits in episodic memory, provided fewer steps relevant to the given solution than their comparison group. Segmenting the descriptions into details using the methods of the Autobiographical Interview, we also found that patients with TLE and older adults provided fewer internal (episodic) details but a similar number of external (semantic) details compared to their control group. These findings are the first to demonstrate that processes underlying episodic memory, in particular those enabling the retrieval of experiential detail and episodic simulation may contribute to open-ended problem solving. Given that we examined groups with medial temporal lobe lesions and known episodic memory dysfunction, these results further suggest that the negative consequences of episodic memory loss resulting from damage to or deterioration of the medial temporal lobes extend beyond that of memory to include other domains, such as problem solving.