Building the blocks of executive functioning: differentiating early developing processes contributing to executive functioning skills.

The neural processes that underlie executive function begin to develop in infancy. However, it is unclear how the behavior manifested by these processes are related or if they can be differentiated early in development. This study seeks to examine early emerging executive functioning skills in monkeys (Macaca fascicularis) by using an error analysis approach where traditional measures of the tasks, as well as identification of major error patterns are related. Results show that during the infancy and early juvenile period, two processes that help support set-maintenance could be differentiated: modulation of responses to novelty and persistence despite negative feedback. The results suggest that these two aspects of set-maintenance were largely independent. Modulation of responses to novelty was most prominent in the infancy and early juvenile period. The ability to persist with a response set despite negative feedback emerged in the early juvenile period and was related to task performance until the end of the study.