Rich interpretation vs. deflationary accounts in cognitive development: the case of means-end skills in 7-month-old infants

Seven-month-old infants appear to learn means-end skills, such as pushing a button to retrieve a distant toy (Psychological Review 104 (1997) 686). The present studies tested whether such apparent means-end behaviors are genuine, or simply the repetition of trained behaviors under conditions of greatest arousal, as suggested by a dynamic systems reinterpretation. When infants were trained to repeat behaviors that did not serve as means to retrieving toys (pushing a button to light a set of distant lights), their button-pushing differed significantly from infants for whom button-pushing served as a means for retrieving toys. Further, infants demonstrated means-end skills with behaviors that they had not been trained to repeat. Implications for early means-end abilities and for debates surrounding the interpretation of infant behavior are discussed.     

Mental health condition of the only-child: a study of urban and rural high school students in China

The mental health of the only-child continues to generate interest in research literature. The present study examines the issue in China, where the one-child phenomenon is highest due to deliberate government policy. Subjects are 299 and 333 students in two high-rank high schools in urban Harebin and rural Qing an Xian, respectively (mean age = 17.2 years). Both locations are in the Heilongjiang Sheng Province of China. Results showed that urban only-children experienced significantly lower love awareness from family, higher neurotic and social depression, trait anxiety, perceived stressors, and interpersonal dependency than did urban non-only children. No significant differences were found in the rural only- and non-only children. Low love awareness from parents and peers was associated with high negative mental health conditions in the children. Low love awareness also precipitated perceived stressors which resulted in negative mental health in the covariance structure analysis.     

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.     

Hebbian learning and development

Hebbian learning is a biologically plausible and ecologically valid learning mechanism. In Hebbian learning, 'units that fire together, wire together'. Such learning may occur at the neural level in terms of long-term potentiation (LTP) and long-term depression (LTD). Many features of Hebbian learning are relevant to developmental theorizing, including its self-organizing nature and its ability to extract statistical regularities from the environment. Hebbian learning mechanisms may also play an important role in critical periods during development, and in a number of other developmental phenomena.     

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.     

Opposite effects of anxiety and depressive symptoms on executive function: The case of selecting among competing options

People constantly face the need to choose one option from among many, such as when selecting words to express a thought. Selecting between many options can be difficult for anyone, and can feel overwhelming for individuals with elevated anxiety. The current study demonstrates that anxiety is associated with impaired selection across three different verbal tasks, and tests the specificity of this finding to anxiety. Anxiety and depression frequently co-occur; thus, it might be assumed that they would demonstrate similar associations with selection, although they also have distinct profiles of symptoms, neuroanatomy and neurochemistry. Here, we report for the first time that anxiety and depressive symptoms counter-intuitively have opposite effects on selection among competing options. Specifically, whereas anxiety symptoms are associated with impairments in verbal selection, depressive symptoms are associated with better selection performance. Implications for understanding the mechanisms of anxiety, depression and selection are discussed.     

Speed isn't everything: complex processing speed measures mask individual differences and developmental changes in executive control

The rate at which people process information appears to influence many aspects of cognition across the lifespan. However, many commonly accepted measures of ‘processing speed’ may require goal maintenance, manipulation of information in working memory, and decision‐making, blurring the distinction between processing speed and executive control and resulting in overestimation of processing speed contributions to cognition. This concern may apply particularly to studies of developmental change, as even seemingly simple processing speed measures may require executive processes to keep children and older adults on task. We report two new studies and a re‐analysis of a published study, testing predictions about how different processing speed measures influence conclusions about executive control across the lifespan. We find that the choice of processing speed measure affects the relationship observed between processing speed and executive control, in a manner that changes with age, and that choice of processing speed measure affects conclusions about development and the relationship among executive control measures. Implications for understanding processing speed, executive control, and their development are discussed.     

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.     

Why do children perseverate when they seem to know better: Graded working memory,or directed inhibition?

Children sometimes have trouble switching from one task to another, despite demonstrating an awareness of current task demands. This behavior could reflect problems either directly inhibiting previously relevant information or sufficiently activating graded working memory representations for the current task. We tested competing predictions from each account, using a computerized card-sorting task in which we assessed children’s task switching abilities and their response speed to simple questions about current task demands. All children answered these questions correctly, but children who successfully switched tasks responded more quickly to questions than did children who perseverated on previous tasks, even after factoring out processing speed and age. This reaction time difference supports graded working memory accounts, with stronger representations of current task demands aiding both task-switching and responses to questions. This result poses a challenge for directed inhibition accounts, because nothing needs to be inhibited to answer simple questions that lack conflicting information.