Executive functions, strategy use, and task-impurity

In many tasks, subjects develop a better understanding of the task structure over time, and are able to leverage that understanding to create strategies which help them to learn or perform more efficiently. This presents two major obstacles to understanding how subjects learn: Their behavior is non-stationary, in that they may change their strategy over time, resulting in different cognitive and neural processes contributing to learning. And different subjects may adopt different strategies based on their own understanding of the task structure. One of the consequences of these facts is that subjects may actually leverage a wide variety of cognitive and neural systems during the performance of ostensibly “pure” tasks of motor control, memory, or other processes.

We have evidence that subjects’ ability to develop deliberate strategies is related to general executive functions, even in relatively simple tasks. There are also suggestions that – even in the same task – subjects’ performance may correlate with different subcomponents of executive functions depending on the specific response strategy that they have adopted. One of my major interests is in relating individual differences in subcomponents of executive functions to individual differences in strategy use during task performance, and to the propensity to develop strategies in the first place.

In many cases, these strategies clearly leverage subjects’ understanding of some statistical or structural regularity in the task, and so must involve some learning of the underlying task structure. There is a large body of evidence linking this kind of learning to prefrontal-hippocampal circuitry, which forms and updates a cognitive map of this structure, and in turn allows other systems to more efficiently fine-tune the parameters dictating effective behavior. Another major interest of mine is in using the known function of this circuitry – well studied in animal models – to ask questions about how subjects’ gradual learning of the structure of a task informs their decision to implements specific response strategies.