Cognitive Control Adjusts to Behavioral Constraints at Short Timescales

Cognitive functions encompass a large set of abstract constructs used for adapting our behavior to environmental constraints, each of them acting at specific timescales. For example, while working memory operates over several seconds or minutes, decision making occurs over much shorter periods. Solving a behavioral task thus relies on specific cognitive strategies that use several functions over time. Here, we investigated how two macaque monkeys coordinate working memory, selective attention, decision-making and executive control of eye movements during performance of a modified delay match-to-sample task. The economy of this task (including reward expected value and cost of errors) evolves on short timescales within trials. In addition, this task allowed us to manipulate engagement of cognitive resources at longer timescales. Using tools from signal detection theory, we closely analyze how monkeys performances evolve over time and infer their specific strategies in terms of control of cognitive functions. In addition, during covert attention, fixational eye movements and pupil size, provided reliable markers of slow variations in cognitive state across trials, although not of rapid within-trial changes in cognitive control. Together, these results show that each monkey adapted to the same task by implementing individual, dynamically evolving cognitive strategies across multiple timescales.