Cognitive Flexibility Improves Memory for Delayed Intentions

The ability to delay the execution of a goal until the appropriate time, prospective memory (PM), can be supported by the following two different cognitive control strategies: proactive control involving working memory maintenance of the goal and active monitoring of the environment; or reactive control relying on timely retrieval of goal information from episodic memory. Certain situations tend to favor each strategy, but the manner in which individuals adjust their strategy in response to changes in the environment is unknown. Across two experiments, human participants performed a delayed-recognition PM task embedded in an ongoing visual search task that fluctuated in difficulty. A control strategy was identified from moment to moment using reaction time costs and fMRI measures of goal maintenance. We found that people fluidly modified control strategies in accordance with changes in task demands (e.g., shifting toward proactive control when task difficulty decreased). This cognitive flexibility proved adaptive as it was associated with improved PM performance.