Effects of affective factors on cognitive control engagement in childhood and adulthood

Childhood is a period of protracted gains in cognitive control, with increasingly flexible and efficient engagement of cognitive resources as a function of task demands. In particular, children progressively shift from relying on “as-needed” reactive control engagement at preschool age to more anticipatory proactive control engagement by middle childhood. Cognitive control is usually implemented in emotionally or motivationally charged contexts in real-world, which may present both challenges and opportunities for control engagement during childhood. The aim of this thesis was to examine how affective factors influence cognitive control in children, particularly the temporal dynamics of control engagement. Using electroencephalography (EEG), Study 1 showed that both positive stimuli and external rewards encouraged children and adults to engage practive control in a cued task-switching paradigm, but in different ways: provision of external rewards promoted proactive cue alertness, whereas the presence of positive stimuli enhanced proactive task selection. Study 2 leveraged fMRI to examine the brain circuitry supporting these beneficial effects in young adults. Provising of external rewards elicited greater cue-locked activation in the lateral frontal cortex, while no effect of positive stimuli on brain activation was detected. Study 3 used pupillometry to further investigate the effects of different reward types on control engagement. Both performance contingent and non-contingent rewards, provided as either a sustained incentive context or a transient incentive, improved proactive control engagement in the AX-CPT in childhood as well as adulthood. Willingness to engage cognitive effort, which was not influenced by reward contingency, mediated partially the effect of age on proactive control engagement. Finally, Study 4 compared the effects of social and non-social rewards on cognitive control engagement in an online version of AX-CPT, with other important reward dimensions being balanced between reward types. Social rewards enhanced cognitive control performance but did not influence whether control was engaged reactively or proactively in both preschool and school-aged children, whereas no effect of non-social rewards was observed. Together, these findings indicate that external rewards and, to a lesser extent, positive stimuli, can help children strategically upregulate cognitive control engagement by promoting a proactive mode of control, although these effects do not always translate into behavioural benefits. They have important implications for assessing and promoting cognitive control both in and outside of the lab