How memory guides value-based decisions

Daphna Shohamy
Columbia University

Memory is central to adaptive behavior, allowing past experience to improve choices. 
However, the neurobiological mechanisms by which memory influences decisions and 
the consequences for behavior remain poorly understood. In particular, current theories 
of value-based decisions focus on how the outcome of a repeated choice can influence 
the likelihood of making the same choice later on. But, for memory to adaptively guide 
decisions, there must also be mechanisms that allow for rare, unique and flexible 
influences of memory on behavior. I will present evidence for a critical role for memory 
mechanisms in the hippocampus in biasing value-based decisions, focusing on two 
distinct mechanisms. The first concerns the integration of information across discrete 
past events in the service of generalization from past experience when making new 
decisions. The second concerns the use of memories for rare one-time events towards 
prediction of reward. Finally, I will discuss how the hippocampus interacts with 
incremental habit learning in the striatum and the circumstances under which these 
different forms of learning guide decisions.