How does the hippocampus shape decisions?

Making optimal decisions depends on an appreciation of the value of choices. An important source of information about value comes from memory for prior experience. Such value-based learning has historically been considered the domain of a striatal memory system. However, recent developments suggest that memorial representations supported by the hippocampus may also contribute to decision making. Unlike striatal representations, hippocampal ones are flexible; they can be modified and updated as new information is acquired. In this paper we argue that the hippocampus plays a pivotal role in value-based decision making via three flexible learning mechanisms: (1) updating, (2) generalization, and (3) construction.