Dynamic adjustments of cognitive control across adolescence

Cognitive control refers to our ability to stay on task even in the face of distractions. During task performance, control is dynamically adjusted trial-by-trial, based on changes in task demands (e.g., the occurrence of response conflict). In my thesis, I investigated how the ability to dynamically regulate control levels in response to conflict changes across adolescence when control-related brain areas such as the anterior cingulate cortex are still undergoing maturation. I also examined whether the frequency of lapses in attention during a task (mind-wandering; MW) is related to age and dynamic adjustments of control. Before addressing my central research questions, I first investigated whether dynamic control adjustments are motivated by the aversive nature of response conflict using an affective priming paradigm, but found no robust evidence for this hypothesis (Chapter 2), therefore this avenue was not pursued further. Across two subsequent studies (Chapters 3 & 4) I found no significant age-related differences in the size of the congruency sequence effect (CSE) - an effect hypothesized to reflect dynamic control adjustments - between adolescents and young adults in reaction time on a Simon and a flanker task. However, adolescents did show less flexible and less temporally consistent recruitment of control processes in response to conflict at the neural level as indicated by non-adult-like dynamics in the theta frequency range (4-7 Hz) during the flanker task (Chapter 4). MW frequency was inconsistently related to age (Chapters 3 & 4), however, it did appear to correlate negatively with CSE magnitude. Using a modified flanker task, I examined this association in Chapter 5 but the relationship did not replicate. In sum, this thesis provides some evidence for the protracted maturation of control, however, it also suggests that certain aspects of control, such as the ability to dynamically regulate control levels mature early on.