Memory and decision making.

The only reason we remember things is to make better decisions. What is memory? Memory can be defined as any physical change that carries information about the historical past. Typically, in animal systems, memory is stored in physical changes inside How these physical changes affect information processing depends on how those systems compute information processing. In practice, memory needs to be encoded in a representational form easily accessed by specific computational processes. There will be tradeoffs in these representational forms between generalization and specificity, between detail and accessibility, and between storage size and these other issues These tradeoffs suggest that there should be multiple memory systems, each with representational forms optimized for different aspects of these tradeoffs Similarly, we can ask What is a decision? Following the definitions in Redish (2013), in order to operationally define decision-making such that it can be easily recognized and observed, we define decision-making as the process of selecting an action. At its most general, an action is anything that physically affects the world — thus muscle movements (Grillner, 2003; Llinas, 2001) and social speech acts (Searle, 1965) are both decisions, as are physiological processes such as salivation (Pavlov, 1927). Because we are physical beings, a decision that changes one's internal (computational) state can also be considered an action. And, of course, choosing not to act is also a decision-process. This means that any process that leads to the selection of an action from a set of possible actions is a decision. As with memory, decisions depend on tradeoffs between factors such as generalization and specificity, and between computational speed and flexibility. Therefore, as has been found to be the case with memory, there are likely to be multiple decision-making systems, each with computational processes optimized for different aspects of these trade-These computational processes select actions that reflect an interaction between one's needs and desires (goals, motivation), external cues (information about the current state of the world), and internal representations of one's historical experience (i.e. memory). These two definitions imply a close relationship between memory and decision-making systems, particularly in their multiplicity of computational components. Where decision-making processes fall in terms of their tradeoffs is going to depend in large part on the computational availability of memory representations—a memory representation that provides quick generalization but little specificity is going to produce decisions that are fast, but inflexible, while a memory representation that provides many details, …