Young children engage cognitive control reactively in response to events, rather than proactively preparing for events. Such limitations in executive control have been explained in terms of fundamental constraints on children's cognitive capacities. Alternatively, young children might be capable of proactive control but differ from older children in their metacognitive decisions regarding when to engage proactive control. We examined these possibilities in three conditions of a task-switching paradigm, varying in whether task cues were available before or after target onset. RTs, ERPs, and pupil dilation showed that 5-year-olds did engage in advance preparation, a critical aspect of proactive control, but only when reactive control was made more difficult, whereas 10-year-olds engaged in proactive control whenever possible. These findings highlight metacognitive processes in children's cognitive control, an understudied aspect of executive control development.

People must constantly select among potential thoughts and actions in the face of competition from (a) multiple task-relevant options (underdetermined competition) and (b) strongly dominant options that are not appropriate in the current context (prepotent competition). These types of competition are ubiquitous during language production. In this work, we investigate the neural mechanisms that allow individuals to effectively manage these cognitive control demands and to quickly choose words with few errors. Using fMRI, we directly contrast underdetermined and prepotent competition within the same task (verb generation) for the first time, allowing localization of the neural substrates supporting the resolution of these two types of competition. Using a neural network model, we investigate the possible mechanisms by which these brain regions support selection. Together, our findings demonstrate that all competition is not alike: resolving prepotent competition and resolving underdetermined competition rely on partly dissociable neural substrates and mechanisms. Specifically, activation of left ventrolateral pFC is specific to resolving underdetermined competition between multiple appropriate responses, most likely via competitive lateral inhibition. In contrast, activation of left dorsolateral pFC is sensitive to both underdetermined competition and prepotent competition from response options that are inappropriate in the current context. This region likely provides top–down support for task-relevant responses, which enables them to out-compete prepotent responses in the selection process that occurs in left ventrolateral pFC.

Individuals vary greatly in their ability to select one item or response when presented with a multitude of options. Here we investigate the neural underpinnings of these individual differences. Using magnetic resonance spectroscopy, we found that the balance of inhibitory versus excitatory neurotransmitters in pFC predicts the ability to select among task-relevant options in two language production tasks. The greater an individual's concentration of GABA relative to glutamate in the lateral pFC, the more quickly he or she could select a relevant word from among competing options. This outcome is consistent with our computational modeling of this task [Snyder, H. R., Hutchison, N., Nyhus, E., Curran, T., Banich, M. T., O'Reilly, R. C., et al. Neural inhibition enables selection during language processing. Proceedings of the National Academy of Sciences, U.S.A., 107, 16483–16488, 2010], which predicts that greater net inhibition in pFC increases the efficiency of resolving competition among task-relevant options. Moreover, the association with the GABA/glutamate ratio was specific to selection and was not observed for executive function ability in general. These findings are the first to link the balance of excitatory and inhibitory neural transmission in pFC to specific aspects of executive function.

When we speak, we constantly retrieve and select words for production in the face of multiple possible alternatives. Our ability to respond in such underdetermined situations is supported by left ventrolateral prefrontal cortical (VLPFC) regions, but there is active debate about whether these regions support (1) selection between competing alternatives, (2) controlled retrieval from semantic memory, or (3) selection and controlled retrieval in distinct subregions of VLPFC (selection in mid-VLPFC and controlled retrieval in anterior VLPFC). Each of these theories has been supported by some prior evidence but challenged by other findings, leaving the debate unresolved. We propose that these discrepancies in the previous literature reflect problems in the way that selection and controlled retrieval processes have been operationalized and measured. Using improved measures, we find that shared neural substrates in left VLPFC support both selection and controlled retrieval, with no dissociation between mid and anterior regions. Moreover, selection and retrieval demands interact in left VLPFC, such that selection effects are greatest when retrieval demands are low, consistent with prior behavioral findings. These findings enable a synthesis and reinterpretation of prior evidence and suggest that the ability to respond in underdetermined situations is affected by both selection and retrieval mechanisms for verbal material subserved by left VLPFC, and these processes interact in meaningful ways.

Everyone perseverates at one time or another, repeating previous behaviors when they are no longer appropriate. Such perseveration often occurs in situations with working memory demands, and the ability to overcome perseveration has been linked to brain regions critical for working memory. Many theories thus explain perseveration in terms of working memory deficits. However, perseveration also occurs in situations without apparent working memory demands, in which the visible environment specifies appropriate behavior. Such findings appear to challenge working memory accounts of perseveration. To evaluate this challenge, a neural network model of a working memory account of perseveration was tested on tasks with visible solutions. With advances in the mechanisms that support working memory, networks became increasingly able to attend to relevant information in the environment. These developments led to improvements in performance on tasks with visible solutions, paralleling the developmental progression observed in infants. The simulations demonstrate how mechanisms of working memory can subserve perseveration and success on tasks with and without obvious memory demands. In both types of tasks, controlled processing occurs through the activation of task-relevant representations, which provide top-down biasing of other processing pathways. More generally, the simulations demonstrate how common mechanisms can support working memory and attention.

Visual object representation was studied in free-ranging rhesus monkeys. To facilitate comparison with humans, and to provide a new tool for neurophysiologists, we used a looking time procedure originally developed for studies of human infants. Monkeys' looking times were measured to displays with one or two distinct objects, separated or together, stationary or moving. Results indicate that rhesus monkeys used featural information to parse the displays into distinct objects, and they found events in which distinct objects moved together more novel or unnatural than events in which distinct objects moved separately. These findings show both common-alities and contrasts with those obtained from human infants. We discuss their implications for the development and neural mechanisms of higher-level vision.