Interaction between the development of postural control and the executive function of attention

The authors examined the interaction between the development of postural control and the development of the executive function of attention in 13 children and 6 adults in dual-task conditions. Participants performed an attentionally demanding cognitive task and a postural task simultaneously. The authors equalized the attentional load of the cognitive task across age groups. Comparative changes in the center of pressure in dual- and single-task conditions indicated that dual tasks interfered with postural performance in the wide stance (WS) and the modified Romberg stance (RS). Children at 4-6 years of age (but not children at ages 7-12 years of age or adults) experienced postural control interference in both stance positions, but interference was greater in the RS (p = .018). For all participants, cognitive task performance in RS was unchanged from that in WS. The knowledge gained from the results of this study will contribute to the design and implementation of academic and preacademic programming for young children. Their performance of an intentionally demanding cognitive task would be enhanced by the provision of appropriately sized desks and chairs or their use of an alternate, less demanding position.     

Measuring the executive regulation of emotion with self-rating scales in a nonclinical population

Prefrontal systems play an important role in the regulation of emotion as evidenced by clinical neuroimaging studies. Both subjective and objective neuropsychological tests provide functional evidence of executive dysfunction in emotional deregulation. The present authors evaluated these relationships here in a nonclinical community sample using the Frontal Systems Behavior Scale, Profile of Mood States (POMS), and Depression Anxiety Stress Scales (DASS). Positive correlations uniformly emerged between prefrontal system dysfunction and negative emotional states (anger, depression, anxiety, stress, confusion, and fatigue), whereas positive emotion (vigor) showed a modest inverse correlation with prefrontal system dysfunction, even after control for demographic influences. These relationships may result from cognitive strategies for managing emotion mediated by reciprocal connections between prefrontal systems and the limbic system. The findings corroborated those of other methodologies, supporting the Frontal Systems Behavior Scale (FrSBe) as a valid tool to measure prefrontal function in nonclinical populations.     

Cortico-subcortical contributions to executive control

The term "executive functions" refers to a range of cognitive processes, their common feature being the coordination of information processing and action control. Cortico-subcortical circuits which connect the prefrontal cortex (PFC), the basal ganglia and the cerebellum via the thalamus are believed to serve as neuroanatomical substrates of executive processing. This paper focuses on information processing related to executive functions by the PFC and related subcortical regions. Findings are mainly derived from neuropsychological investigations of brain-damaged patients but also from imaging studies in healthy subjects. There is evidence for subtle differences between these regions with respect to the cognitive mechanisms contributing to inhibition of habitual responses, task management/multitasking and set shifting, although the data base is sparse so far.     

The executive control of mnemonic activity

The present study focused on the executive monitoring of a rehearsal strategy by sixth (11 years 5 months), tenth (15 years 8 months), and twelfth (17 years 9 months) graders and adults (27 years 4 months). The results showed that all of the adults spontaneously adopted an “optimal” strategy and generalized it to a second task. However, none of the sixth graders and only two tenth and three twelfth graders did so. All of the school subjects subsequently trained to rehearse, maintained the strategy without prompting, and showed evidence of transfer. In comparison to adults, the trained subjects' generalized routines became more similar to the adults' as grade increased. This study supports the notion that efficient executive functioning includes the case where continued use of a mnemonic routine is a reasonable response to an objective change in an information-processing task.     

The executive control of face memory

Patients with frontal lobe damage and cognitively normal elderly individuals demonstrate increased susceptibility to false facial recognition. In this paper we review neuropsychological evidence consistent with the notion that the common functional impairment underlying face memory distortions in both subject populations is a context recollection/source monitoring deficit, coupled with excessive reliance on relatively preserved facial familiarity signals in recognition decisions. In particular, we suggest that due to the breakdown of strategic memory retrieval, monitoring, and decision operations, individuals with frontal lobe impairment caused by focal damage or age-related functional decline do not have a reliable mechanism for attributing the experience of familiarity to the correct context or source. Memory illusions are mostly apparent under conditions of uncertainty when the face cue does not directly elicit relevant identity-specific contextual information, leaving the source of familiarity unspecified or ambiguous. Based on these findings, we propose that remembering faces is a constructive process that requires dynamic interactions between temporal lobe memory systems that operate in an automatic or bottom-up fashion and frontal executive systems that provide strategic top-down control of recollection. Executive memory control functions implemented by prefrontal cortex play a critical role in suppressing false facial recognition and related source memory misattributions.     

Aging and time-sharing aspects of executive control

A particularly important aspect of executive functioning involves the ability to coordinate two simultaneous activities. The role of this aspect of executive functioning in adult-age differences in cognitive performance was examined in a study involving 150 adults between 20 and 91 years of age who performed the same visual-motor tracking task with three different primary tasks. The participants also performed several additional cognitive tasks that allowed examination of the relation of time-sharing efficiency to other types of cognitive functioning The results were consistent with the existence of a distinct time-sharing ability because the time-sharing costs in the three dual-task combinations were significantly correlated with one another but only weakly correlated with other cognitive variables. Increased age was associated with reductions in time-sharing ability, and greater efficiency in performing two tasks at once was associated with better performance on tasks assessing spatial, reasoning, and memory abilities. Although this pattern is what one would expect if executive processes contribute to age differences in cognitive functioning, the effects were smaller than those associated with a perceptual speed construct.     

Intact emotion-induced recognition bias in neuropsychological patients with executive control deficits

In recognition memory tasks, emotionally negative words are judged more often as "old" relative to emotionally neutral words, suggesting a shift in response bias. We wondered whether this bias shift was due to the flexible regulation of executive control during memory retrieval. To address this question, we investigated individuals with high variability in executive control functions. As expected, we observed that emotional word meaning did indeed have a strong influence on the bias toward responding "old," independent of recognition accuracy and overall response bias. However, these effects were uncorrelated with executive control, as measured by the Trail Making Test, and were fully intact, even in a sample of hospitalized neurological patients with severe executive dysfunctions, some of whom had marked damage in fronto-thalamo-striatal networks. Having concluded that the emotion-induced bias must develop on different grounds, we went on to discuss alternative explanations.     

Components of executive control with advantages for bilingual children in two cultures

The present study used a behavioral version of an anti-saccade task, called the ‘faces task’, developed by [Bialystok, E., Craik, F. I. M., & Ryan, J. (2006). Executive control in a modified anti-saccade task: Effects of aging and bilingualism. Journal of Experimental Psychology: Learning, Memory, and Cognition, 32, 1341-1354] to isolate the components of executive functioning responsible for previously reported differences between monolingual and bilingual children and to determine the generality of these differences by comparing bilinguals in two cultures. Three components of executive control were investigated: response suppression, inhibitory control, and cognitive flexibility. Ninety children, 8-years old, belonged to one of three groups: monolinguals in Canada, bilinguals in Canada, and bilinguals in India. The bilingual children in both settings were faster than monolinguals in conditions based on inhibitory control and cognitive flexibility but there was no significant difference between groups in response suppression or on a control condition that did not involve executive control. The children in the two bilingual groups performed equivalently to each other and differently from the monolinguals on all measures in which there were group differences, consistent with the interpretation that bilingualism is responsible for the enhanced executive control. These results contribute to understanding the mechanism responsible for the reported bilingual advantages by identifying the processes that are modified by bilingualism and establishing the generality of these findings across bilingual experiences. They also contribute to theoretical conceptions of the components of executive control and their development.     

Age-related differences in executive control of working memory

In two experiments, we used dual-task methodology to assess the effect of aging on executive control of working memory. We hypothesized that (1) age-related dual-task costs would be observed even when individual tasks represent different perceptual modalities; (2) age would modulate the effect of increased temporal overlap on dual-task performance; and (3) the vulnerability of specific memory mechanisms to interference would be age related. We found that aging was associated with disproportionate dual-task costs that increased when extending the overlap between individual tasks. The effect of interference with encoding, and arguably output, was disproportionately larger in old than in young individuals. Ensuring that individual tasks represent different perceptual modalities is important but insufficient when using dual-task methodology to assess the effect of aging on executive function. The degree of temporal overlap between individual tasks and the sensitivity of specific memory operations to interference should be considered, as well.     

The role of executive control in tool use

Comparing cognitive functions between humans and nonhuman primates is helpful for understanding human tool use. We comment on the latest insights from comparative research on executive control functions. Based on our own work, we discuss how even a mental function in which non-human primates outperform humans might have played a key role in the development of tool use.     

The role of the executive functions in school achievement at the end of Grade 1

The aim of this study was to determine the role of executive functions (EFs) in early school achievement when a variety of potential confounding factors were controlled. Measures of EF (inhibition, flexibility, and working memory) and school readiness were administered to a sample of 85 kindergartners (39 boys and 46 girls, 5-6 years old). School achievement was then assessed at the end of Grade 1. Results show math and reading/writing skills at the end of Grade 1 to be associated with kindergarten EFs. Only working memory contributed uniquely to the variance in school achievement after all covariates (preacademic abilities, affective variables, and family variables) were controlled and, even then, only with respect to math skills. On the other hand, working memory and inhibition had an indirect effect on reading/writing skills via anger-aggression. EF implication in school achievement is discussed in terms of task demands and child age.     

Biological and psychological development of executive functions.

The purpose of this overview is to provide a background for understanding the relation between the biological maturation of the frontal lobes and the development of the psychological concept of executive functions. In the first section, an interactive hierarchical feedback model is presented as a heuristic way of conceptualizing the relationship of the frontal lobes and executive functions to other brain regions and abilities. The following two sections present a synopsis of research on biological maturation and the psychological development of executive functions.     

Measuring social skill in grade school boys

This study examined positive and negative assertive skill in 60 elementary school boys, grades 3–8. Subjects' role-played responses to standard analogue situations requiring expression of positive and negative assertion were videotaped and rated retrospectively. High- and low-assertive subjects were identified through ratings of overall assertiveness. Results of this study indicate that (1) high- and low-assertive subjects differ on a number of response components which are related to age level and type of assertive situation (positive vs. negative), (2) assertive skill is associated with role-taking (or decentering) ability, (3) teachers tend to perceive their assertive boys as more sociable and interpersonally sensitive than unassertive boys, (4) there is essentially no correlation between teachers' ratings of aggressiveness and separate behavioral ratings of assertive skill, and (5) behavioral ratings of assertiveness show little relationship to self-report or teachers' ratings of assertiveness.This article is based on a dissertation submitted to the Faculty of the Graduate School of Loyola University of Chicago in partial fulfillment of the requirements for the Degree of Doctor of Philosophy. The study was conducted under the direction of the second, third, and fourth authors.     

Examining the development of attention and executive functions in children with a novel paradigm.

The development of attention and executive functions in normal children (7-12 years) was investigated using a novel selective reaching task, which involved reaching as rapidly as possible towards a target, while at times having to ignore a distractor. The information processing paradigm allowed the measurement of various distinct dimensions of behaviour within a single task. The largest improvements in vigilance, set-shifting, response inhibition, selective attention, and impulsive responding were observed to occur between the ages of 8 and 10, with a plateau in performance between 10 and 12 years of age. These findings, consistent with a step-wise model of development, coincide with the observed developmental spurt in frontal brain functions between 7 and 10 years of age, and indicate that attention and executive functions develop in parallel. This task appears to be a useful research tool in the assessment of attention and executive functions, within a single task. Thus it may have a role in determining which cognitive functions are most affected in different childhood disorders.     

Threat facilitates subsequent executive control during anxious mood

Dual competition framework (DCF) posits that low-level threat may facilitate behavioral performance by influencing executive control functions. Anxiety is thought to strengthen this effect by enhancing threat's affective significance. To test these ideas directly, we examined the effects of low-level threat and experimentally induced anxiety on one executive control function, the efficiency of response inhibition. In Study 1, briefly presented stimuli that were mildly threatening (i.e., fearful faces) relative to nonthreatening (i.e., neutral faces) led to facilitated executive control efficiency during experimentally induced anxiety. No such effect was observed during an equally arousing, experimentally induced happy mood state. In Study 2, we assessed the effects of low-level threat, experimentally induced anxiety, and individual differences in trait anxiety on executive control efficiency. Consistent with Study 1, fearful relative to neutral faces led to facilitated executive control efficiency during experimentally induced anxiety. No such effect was observed during an experimentally induced neutral mood state. Moreover, individual differences in trait anxiety did not moderate the effects of threat and anxiety on executive control efficiency. The findings are partially consistent with the predictions of DCF in that low-level threat improved executive control, at least during a state of anxiety.     

Differential course of executive control changes during normal aging

Normal aging has been associated with executive control deficits, but it is as yet unclear whether different executive subprocesses are differentially affected during the course of aging. The present study aimed to investigate age effects on a range of executive control subcomponents. Four consecutive age groups (20-30 years, 31-45 years, 46-60 years, 61-75 years), matched on present state IQ and mood, were compared on tasks of strategic memory processing, verbal fluency, reasoning, inhibition, task management, and self-rating of executive abilities. Deficits concerning the suppression of habitual and experimentally induced prepotent response tendencies and the ability to efficiently divide attention were observed in subjects over 60 years of age compared to the younger groups, while memory, verbal fluency, and reasoning were largely unaffected. Results suggest a sharp decline of executive function after age 60 and a differential course of different executive subcomponents across aging, adding further support to a multi-dimensional model of executive function.     

Modes of executive control in sequence learning: from stimulus-based to plan-based control

The authors argue that human sequential learning is often but not always characterized by a shift from stimulus- to plan-based action control. To diagnose this shift, they manipulated the frequency of 1st-order transitions in a repeated manual left-right sequence, assuming that performance is sensitive to frequency-induced biases under stimulus- but not plan-based control. Indeed, frequency biases tended to disappear with practice, but only for explicit learners. This tendency was facilitated by visual-verbal target stimuli, response-contingent sounds, and intentional instructions and hampered by auditory (but not visual) noise. Findings are interpreted within an event-coding model of action control, which holds that plans for sequences of discrete actions are coded phonetically, integrating order and relative timing. The model distinguishes between plan acquisition, linked to explicit knowledge, and plan execution, linked to the action control mode.     

Color-object interference: Further tests of an executive control account

Young children are slower in naming the color of a meaningful picture than in naming the color of an abstract form (Stroop-like color-object interference). The current experiments tested an executive control account of this phenomenon. First, color-object interference was observed in 6- and 8-year-olds but not in 12- and 16-year-olds (Experiment 1). Second, meaningful pictures did not interfere in 5- to 7-year-olds’ manual sorting of objects on the basis of color (Experiment 2) or in their naming the number of colored objects in the display, that is, subitizing (Experiment 3). These findings provide support for the view that color-object interference results from the children’s immature inhibition of the prepotent but irrelevant task of object naming.