Yuko Munakata

A unified framework for inhibitory control

Inhibiting unwanted thoughts, actions and emotions figures centrally in daily life, and the prefrontal cortex (PFC) is widely viewed as a source of this inhibitory control. We argue that the function of the PFC is best understood in terms of representing and actively maintaining abstract information, such as goals, which produces two types of inhibitory effects on other brain regions. Inhibition of some subcortical regions takes a directed global form, with prefrontal regions providing contextual information relevant to when to inhibit all processing in a region. Inhibition within neocortical (and some subcortical) regions takes an indirect competitive form, with prefrontal regions providing excitation of goal-relevant options. These distinctions are crucial for understanding the mechanisms of inhibition and how they can be impaired or improved.

Processes of change in brain and cognitive development

We review recent advances in the understanding of the mechanisms of change that underlie cognitive development. We begin by describing error-driven, self-organizing and constructivist learning systems. These powerful mechanisms can be constrained by intrinsic factors, other brain systems and/or the physical and social environment of the developing child. The results of constrained learning are representations that themselves are transformed during development. One type of transformation involves the increasing specialization and localization of representations, resulting in a neurocognitive system with more dissociated streams of processing with complementary computational functions. In human development, integration between such streams of processing might occur through the mediation of language.

Infant perseveration and implications for object permanence theories: A PDP model of the AB task

From the earliest ages at which infants search for hidden objects, they make the AB error, searching perseveratively at previous rather than current hiding locations (Piaget, 1954). This paper presents a parallel distributed processing (PDP) model that instantiates an explicit set of processing mechanisms to account for a large and diverse set of data on infants’ AB errors. The model demonstrates how basic processes–the formation of latent memory traces and their interaction with developing active memory traces–can provide a unifying framework for understanding why and when infants perseverate. Novel predictions from the model are discussed, together with its challenges for theories that posit a concept of object permanence in the first year of life.

Graded representations in behavioral dissociations

Why do people sometimes seem to know things when they are tested in one way, while seeming unaware of this information when tested in a different way? Such task-dependent behaviors, or dissociations, often occur in infants and children, and in adults following brain damage. To explain these dissociations, researchers have posited separable knowledge systems that are differentially tapped by various tasks, develop at different rates and can be selectively impaired. There is an alternative account in which knowledge is viewed as graded in nature. Certain tasks tap weaker representations, while other tasks require stronger representations, leading to dissociations in behavior. The graded representations approach addresses dissociations observed in perception, attention, memory, executive functioning and language, and has implications for the organization, development and impairment of our cognitive systems.

Developing Cognitive Control Three Key Transitions

The ability to flexibly break out of routine behaviors develops gradually and is essential for success in life. In this article, we discuss three key developmental transitions toward more flexible behavior. First, children develop an increasing ability to overcome habits by engaging cognitive control in response to environmental signals. Second, children shift from recruiting cognitive control reactively, as needed in the moment, to recruiting cognitive control proactively, in preparation for needing it. Third, children shift from relying on environmental signals for engaging cognitive control to becoming more self-directed. All three transitions can be understood in terms of the development of increasingly active and abstract goal representations in the prefrontal cortex.

Pupillometric and behavioral markers of a developmental shift in the temporal dynamics of cognitive control.

The capacity to anticipate and prepare for future events is thought to be critical for cognitive control. Dominant accounts of cognitive control treat the developing system as merely a weaker version of the adult system, progressively strengthening over time. Using the AX Continuous Performance Task (AX-CPT) in combination with high-resolution pupillometry, we find that whereas 8-year-old children resemble adults in their proactive use of cognitive control, 3.5-year-old children exhibit a qualitatively different, reactive form of cognitive control, responding to events only as they unfold and retrieving information from memory as needed in the moment. These results demonstrate the need to reconsider the origins of cognitive control and the basis for childrens behaviors across domains.

Connectionist models of development

How have connectionist models informed the study of development? This paper considers three contributions from specific models. First, connectionist models have proven useful for exploring nonlinear dynamics and emergent properties, and their role in nonlinear developmental trajectories, critical periods and developmental disorders. Second, connectionist models have informed the study of the representations that lead to behavioral dissociations. Third, connectionist models have provided insight into neural mechanisms, and why different brain regions are specialized for different functions. Connectionist and dynamic systems approaches to development have differed, with connectionist approaches focused on learning processes and representations in cognitive tasks, and dynamic systems approaches focused on mathematical characterizations of physical elements of the system and their interactions with the environment. The two approaches also share much in common, such as their emphasis on continuous, nonlinear processes and their broad application to a range of behaviors.

All Together Now: When Dissociations Between Knowledge and Action Disappear

Why do people sometimes seem to know things but fail to act appropriately on the basis of this knowledge? Such dissociations between knowledge and action often occur in infants and children, and in adults following brain damage. These dissociations have supported inferences about the organization of cognitive processes (e.g., separable knowledge and action systems) and their development (e.g., knowledge systems develop before action systems). The current study tested the basis for knowledge-action dissociations in a card-sorting task in which children typically correctly answer questions about sorting rules while sorting cards incorrectly. When questions and sorting measures were more closely equated for the amount of conflict that needed to be resolved for a correct response, children showed no systematic dissociation between knowledge and action. The results challenge standard interpretations of knowledge-action dissociations and support an alternative account based on graded knowledge representations.

Cognitive control reflects context monitoring, not motoric stopping, in response inhibition.

The inhibition of unwanted behaviors is considered an effortful and controlled ability. However, inhibition also requires the detection of contexts indicating that old behaviors may be inappropriate – in other words, inhibition requires the ability to monitor context in the service of goals, which we refer to as context-monitoring. Using behavioral, neuroimaging, electrophysiological and computational approaches, we tested whether motoric stopping per se is the cognitively-controlled process supporting response inhibition, or whether context-monitoring may fill this role. Our results demonstrate that inhibition does not require control mechanisms beyond those involved in context-monitoring, and that such control mechanisms are the same regardless of stopping demands. These results challenge dominant accounts of inhibitory control, which posit that motoric stopping is the cognitively-controlled process of response inhibition, and clarify emerging debates on the frontal substrates of response inhibition by replacing the centrality of controlled mechanisms for motoric stopping with context-monitoring.

Developmental cognitive neuroscience: progress and potential

Developmental cognitive neuroscience is an evolving field that investigates the relations between neural and cognitive development. Lying at the intersection of diverse disciplines, work in this area promises to shed light on classic developmental questions, mechanisms subserving developmental change, diagnosis and treatment of developmental disorders, and cognitive and neuroscientific topics traditionally considered outside the domain of development. Fundamental questions include: What are the interrelations between developmental changes in the brain (e.g. in connectivity, chemistry, morphology) and developmental changes in childrens behavior and cognitive abilities (e.g. representational complexity, ability to sustain selective attention, speed of processing)? Why, and how, is learning enhanced during certain periods in development? How is our knowledge organized, and how does this change with development? We discuss preliminary investigations of such questions and directions for future work.