Does physical activity reduce risk for Alzheimer's disease through interaction with the stress neuroendocrine system?

Lack of physical activity (PA) is a risk factor for Alzheimer's disease (AD), and PA interventions are believed to provide an effective non-pharmacological approach for attenuating the symptoms of this disease. However, the mechanism of action of these positive effects is currently unknown. It is possible that the benefits may be at least partially mediated by the effects on the neuroendocrine stress system. Chronic stress can lead to dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis, leading to aberrant basal and circadian patterns of cortisol secretion and a cascade of negative downstream events. These factors have been linked not only to reduced cognitive function but also increased levels of amyloid-β plaques and protein tau "tangles" (the neuropathological hallmarks of AD) in the non-demented mouse models of this disease. However, there is evidence that PA can have restorative effects on the stress neuroendocrine system and related risk factors relevant to AD. We explore the possibility that PA can positively impact upon AD by restoring normative HPA axis function, with consequent downstream effects upon underlying neuropathology and associated cognitive function. We conclude with suggestions for future research to test this hypothesis in patients with AD.     

Does handedness determine which hand leads in a bimanual task?

Right- and left-handers (n = 16 in each group) were tested on a bimanual circle task that required drawing either in the same direction (parallel) or in a mirror symmetrical coordination mode with the two hands. The authors' primary purposes were to examine the effect of circle direction on within-hand and between-hands variables and to determine whether the relation between hand lead and coordination mode (parallel or mirror symmetrical) differs for left- and right-handers. A strong relation was found between lead hand and movement condition, which depended on the direction of the movements and whether the task was parallel or mirror symmetrical. The pattern of results was similar for left- and right-handers on parallel tasks, but group differences were found with respect to mirror symmetrical tasks. At odds with the general claim that the dominant hand leads, the present results indicated that hand dominance does not generally determine which hand leads.     

Does hand dominance affect the use of motor abundance when reaching to uncertain targets?

This study investigated hemispheric differences in utilizing motor abundance to achieve flexible patterns of joint coordination when reaching to uncertain target locations. Right-handed participants reached with each arm to the same central target when its final location was certain or when there was a 66% probability that its location could change after movement initiation. Use of greater motor abundance was observed when participants reached to the central target under target location uncertainty regardless of the arm used to reach. Joint variance associated with variability of movement direction was larger when reaching with the left, non-dominant arm. This arm also exhibited higher hand path variability compared to the dominant arm. These arm differences were not found when the final (central) target location was known in advance. The results provide preliminary evidence for a greater ability of the dominant (right) arm/left hemisphere to decouple directions in joint space. That is, to increase the use of motor abundance without simultaneously inducing unwanted hand path variability requires that joint variations be restricted to a limited subspace of joint space. Hemispheric differences in motor planning did not appear to account for arm differences related to the use of motor abundance.     

Does social support predict smoking abstinence in dual-smoker couples? Evidence from a dyadic approach

Background and Objectives: Romantic partners have a significant influence on their health behaviors. Evidence for the effectiveness of social support for smoking abstinence, however, is mixed and the role of social support for smoking abstinence in dual-smoker couples is understudied.

Design: 77 dual-smoker couples were assessed 30 days after a joint quit attempt using a dyadic approach.

Methods: Received and provided support, self-reported and objectively measured smoking abstinence were assessed from both partners. Actor and partner effects of received and provided support on self-reported and objectively measured smoking abstinence and their difference for men and women were investigated with the Actor–Partner Interdependence Model using multilevel modeling.

Results: A significant actor effect emerged: Higher reports of received emotional support were related to an increased likelihood of objective smoking abstinence for men and women alike. For men only, partner effects of women’s received emotional and instrumental support emerged (p?<?.10): Higher reports of women’s support receipt were associated with an increased likelihood of men’s self-reported abstinence.

Conclusion: Received emotional support seems to play a key role in dual-smoker couple’s abstinence, whereas provided support does not seem to make a difference in successful quitting in dual-smoker couples.     

Does interaction matter? Testing whether a confidence heuristic can replace interaction in collective decision-making

In a range of contexts, individuals arrive at collective decisions by sharing confidence in their judgements. This tendency to evaluate the reliability of information by the confidence with which it is expressed has been termed the ‘confidence heuristic’. We tested two ways of implementing the confidence heuristic in the context of a collective perceptual decision-making task: either directly, by opting for the judgement made with higher confidence, or indirectly, by opting for the faster judgement, exploiting an inverse correlation between confidence and reaction time. We found that the success of these heuristics depends on how similar individuals are in terms of the reliability of their judgements and, more importantly, that for dissimilar individuals such heuristics are dramatically inferior to interaction. Interaction allows individuals to alleviate, but not fully resolve, differences in the reliability of their judgements. We discuss the implications of these findings for models of confidence and collective decision-making.     

Does suppressing the thought of a self-relevant stigma affect interpersonal interaction?

In the current study, we examined the effects of women's suppressing negative gender stereotypes while interacting with a male confederate. Compared with control participants, those who suppressed negative thoughts about women's ability experienced less self-confidence, lower self-esteem, and were more nonverbally submissive during the interaction, particularly if they were high in stigma consciousness (Pinel, 1999). These findings illustrate the negative intra- and interpersonal consequences of stigma suppression.     

Intersensory facilitation in the motor component?

Summary In the bimodal detection task the observer must respond as soon as a signal is presented in either of two modalities (e.g., a tone or a flash). A typical finding is a facilitation of reaction time for redundant signal trials, that is, when both signals are presented simultaneously or with a short delay. Models advanced for this effect imply either statistical facilitation (separate activation) or intersensory facilitation (coactivation). This paper reports a study investigating whether part of the facilitation can be accounted for by coactivation in the motor component. An analysis of the distributions of reaction time differences between left and right hand responses from a double response paradigm gave some evidence in favor of this hypothesis. In particular, our data suggest a u-shaped functional dependence of the amount of facilitation in the motor component on the interstimulus interval.     

Does it really matter whether students' contributions are spoken versus typed in an intelligent tutoring system with natural language?

There is the question of whether learning differs when students speak versus type their responses when interacting with intelligent tutoring systems with natural language dialogues. Theoretical bases exist for three contrasting hypotheses. The speech facilitation hypothesis predicts that spoken input will increase learning, whereas the text facilitation hypothesis predicts typed input will be superior. The modality equivalence hypothesis claims that learning gains will be equivalent. Previous experiments that tested these hypotheses were confounded by automated speech recognition systems with substantial error rates that were detected by learners. We addressed this concern in two experiments via a Wizard of Oz procedure, where a human intercepted the learner's speech and transcribed the utterances before submitting them to the tutor. The overall pattern of the results supported the following conclusions: (1) learning gains associated with spoken and typed input were on par and quantitatively higher than a no-intervention control, (2) participants' evaluations of the session were not influenced by modality, and (3) there were no modality effects associated with differences in prior knowledge and typing proficiency. Although the results generally support the modality equivalence hypothesis, highly motivated learners reported lower cognitive load and demonstrated increased learning when typing compared with speaking. We discuss the implications of our findings for intelligent tutoring systems that can support typed and spoken input.     

Does the coordination of verbal and motor information explain the development of counting in children?

Counting is often considered to be the coordination of two actions: saying the number-words and pointing to each object. We report three experiments to test the hypothesis that this coordination requires the use of the central executive (A. D. Baddeley, 1990), and that the cost of coordination decreases with age. Participants were 5- and 9-year-old children and adults. At all ages tested, the manipulation of the difficulty of each component affected counting performance but did not make coordination more difficult. These results suggest that, at least from the age 5, counting is a procedure in which the control of coordination is not attention demanding.     

What is the motor vehicle crash risk for drivers with a sleep disorder?

In many parts of the world, drivers with serious sleep disorders have restrictions on their licence – with the fitness-to-drive criteria varying across licensing jurisdictions. This study aimed to systematically review the literature that evaluated the available scientific evidence for the relationship between sleep disorders and two driving safety outcome measures: (i) motor vehicle crashes (MVC) and (ii) on-road driving test outcome. This review was registered with PROSPERO in July 2019 (see CRD42019144643). A systematic search of public health, psychology and transport databases was conducted on November 8th, 2019. The quality of evidence for each study was rated using the National Heart, Lung and Blood Institute Quality Assessment tools. Thirty-nine studies published between 1976 and 2015 met the inclusion criteria (n = 9 case-control; n = 24 cohort/cross-sectional; n = 6 before-after). Overall, the quality of evidence for 22 studies was rated as ‘good’, nine as ‘fair’ and eight as ‘poor’. Included studies addressed: sleep apnoea and sleep-related breathing disorders (n = 35); central disorders of hypersomnolence and narcolepsy (n = 5), and insomnia (n = 2), with some studies covering multiple sleep disorders. Of the thirty-five studies specifically investigating MVC risk associated with sleep apnoea, eighteen studies reported an increased risk (n = 11 ‘good’, n = 4 ‘fair’, n = 3 ‘poor’ quality), seven reported no difference in risk (n = 3 ‘good’, n = 4 ‘fair’ quality), and two provided inconclusive findings (n = 1 ‘good’, n = 1 ‘fair’ quality). Most studies suggested that increased sleep apnoea severity was associated with an increased MVC risk. Furthermore, untreated sleep apnoea was predominantly associated with increased risk, whilst decreased risk was associated with Continuous Positive Airway Pressure (CPAP) and uvulopalatopharyngoplasty (UPPP) treatments. Five studies (n = 3 ‘good’, n = 2 ‘fair’ quality) investigated MVC risk associated with disorders of hypersomnolence and narcolepsy, and all reported increased risk. Only two studies investigated MVC risk associated with insomnia, with inconsistent findings: one reporting increased MVC risk (‘good’) and one reporting no difference (‘fair’). Regarding impacts on on-road driving test outcome, our comprehensive search found no studies investigating the association between sleep disorders and this driving safety outcome measure. Notwithstanding the limitations of the included studies, the weight of evidence suggests a moderately elevated MVC risk for drivers with sleep disorders (sleep apnoea; hypersomnia and narcolepsy), with the majority reporting around two and a half times higher risk, and lower risk with treatment. This evidence is consistent with current fitness-to-drive guidelines, most of which specify licence restrictions conditional upon severity, treatment compliance and effective response to treatment. The generalisability of the findings is limited as many identified studies had methodological limitations, were conducted across a wide time period, in numerous licensing jurisdictions with different requirements, and across a diverse range of participant populations. A large-scale, population-based controlled study, in multiple licensing jurisdictions with equivalent licensing and fitness-to-drive requirements, is warranted to rigorously investigate MVC risk and sleep disorders, including evaluating the possible benefit of therapies.     

Can low-cost motion-tracking systems substitute a Polhemus system when researching social motor coordination in children?

Functionally stable and robust interpersonal motor coordination has been found to play an integral role in the effectiveness of social interactions. However, the motion-tracking equipment required to record and objectively measure the dynamic limb and body movements during social interaction has been very costly, cumbersome, and impractical within a non-clinical or non-laboratory setting. Here we examined whether three low-cost motion-tracking options (Microsoft Kinect skeletal tracking of either one limb or whole body and a video-based pixel change method) can be employed to investigate social motor coordination. Of particular interest was the degree to which these low-cost methods of motion tracking could be used to capture and index the coordination dynamics that occurred between a child and an experimenter for three simple social motor coordination tasks in comparison to a more expensive, laboratory-grade motion-tracking system (i.e., a Polhemus Latus system). Overall, the results demonstrated that these low-cost systems cannot substitute the Polhemus system in some tasks. However, the lower-cost Microsoft Kinect skeletal tracking and video pixel change methods were successfully able to index differences in social motor coordination in tasks that involved larger-scale, naturalistic whole body movements, which can be cumbersome and expensive to record with a Polhemus. However, we found the Kinect to be particularly vulnerable to occlusion and the pixel change method to movements that cross the video frame midline. Therefore, particular care needs to be taken in choosing the motion-tracking system that is best suited for the particular research.     

Does self-efficacy mediate transfer effects in the learning of easy and difficult motor skills?

The effect of task difficulty on inter-task transfer is a classic issue in motor learning. We examined the relation between self-efficacy and transfer of learning after practicing different versions of a stick balancing task. Practicing the same task or an easier version led to significant pre- to post-test transfer of learning, whereas practicing a more difficult version did not. Self-efficacy increased modestly from pre- to post-test with easy practice, but decreased significantly with difficult practice. In addition, self-efficacy immediately prior to the post-test was significantly lower after difficult practice than easy or intermediate practice. Self-efficacy immediately prior to the post-test, performance at the end of practice, and pre-test performance explained 75% of the variance in post-test performance. The mediating role of self-efficacy on transfer of learning offers an alternative explanation for recent findings on the superiority of easy-to-difficult transfer and may help clarify inconsistencies in earlier research.     

Does selecting one visual object from several require inhibition of the actions associated with nonselected objects?

Four experiments are described in which 1 visual object (the target) was selected from another (the distractor) according to its color (Experiments 1, 2, and 4) or its relative location (Experiment 3) and then was classified according to a simple geometric property. Object classification was signaled as fast as possible by a precision or power grip response, and this grip was either compatible or incompatible with either object. When targets were selected by color, target-compatible grip responses were facilitated, but distractor-compatible grip responses were impaired. When targets were selected by location, similar results were obtained for target-compatible grip responses, but not distractor-compatible grip responses. These data are explained in terms of the involvement of action codes in object-level selection.     

Does a cognitive map guide choices in the radial-arm maze?

Fifteen rats performed in a standard radial-arm maze task (Experiment 1) and in a modified task with a set of forced choices and a 15-min retention interval prior to completion of the maze (Experiment 2). In addition to the standard measure of choice in the radial-arm maze, orientation toward arms was measured and considered to constitute go-no-go "microchoice" decisions. Rats investigated but rejected many arms. A model of choice was developed in which it was assumed that choice decisions about arms were made independently and that microchoices were not selectively guided toward baited arms. The model performed nearly as well as the rats. These results place important limitations on the theory that choice behavior in the radial-arm maze is guided by a cognitive map.     

Does Cooperation in the Laboratory Reflect the Operation of a Broad Trait?

The Dictator Game, a face valid measure of altruism, and the Trust Game, a face valid measure of trust and trustworthiness, are among the most widely used behavioural measures in human cooperation research. Researchers have observed considerable covariation among these and other economic games, leading them to assert that there exists a general human propensity to cooperate that varies in strength across individuals and manifests itself across a variety of social settings. To formalize this hypothesis, we created an S‐1 bifactor model using 276 participants' Dictator Game and Trust Game decisions. The general factor had significant, moderate associations with self‐reported and peer‐reported altruism, trust, and trustworthiness. Thus, the positive covariation among economic games is not reducible to the games' shared situational features. Two hundred participants returned for a second session. The general factor based on Dictator Game and Trust Game decisions from this session did not significantly predict self‐reported and peer‐reported cooperation, suggesting that experience with economic games causes them to measure different traits from those that are reflected in self‐assessments and peer‐assessments of cooperativeness. © 2018 European Association of Personality Psychology     

Does level of motor competence affect the associations between identity health and self-perceptions in adolescents?

BackgroundAdolescence is a particularly important time for the development of self-perceptions and identity as many environmental and personal factors are influential. One relatively unexplored factor is level of motor competence.AimTo examine the relationship between identity health and self-perceptions in male and female adolescents with low motor competence (LMC) compared to typically developing (TD) adolescents.MethodAdolescents (N = 160, 64.4% males, M_age = 14.45 yrs., SD = 0.75) completed the Adolescent Motor Competence Questionnaire (AMCQ), Assessment of Identity Development in Adolescence (AIDA), and Harter's Self-Perception Profile for Adolescents (SPPA). Based on the AMCQ score, the sample was grouped into LMC and TD. Pearson's product moment correlations between the AIDA and SPPA subscales were derived for gender, competence groups, and gender x competence sub-groups.ResultsOverall, males had lower AIDA scores (healthier identity) than the females and significant associations with all self-perception domains. For females, only scholastic and social competence, physical appearance, behavioural conduct, close friendship and Global Self-worth (GSW) domains were significantly related to their AIDA score. The adolescents in the LMC group had higher AIDA scores (less-healthier identity) and fewer self-perception domains [scholastic competence, physical appearance, behavioural conduct, close friendships and GSW] were associated to their AIDA scores. For the TD group, all self-perception domains were significantly correlated with their AIDA scores. When grouped by gender and motor competence, the TD males had the healthiest identity scores which were strongly associated with all self-perception subdomains. For males with LMC, only scholastic competence, behavioural conduct and GSW domains were significantly related with their identity score. Females from both competence groups reported significant associations between physical appearance, close friendships, behavioural conduct, and social competence domains with their identity scores. Scholastic competence was also significantly associated with identity only for females with LMC.ConclusionPositive self-perceptions across a range of domains are associated with a healthier identity, but differ according to level of motor competence and gender. For those with LMC, the self-perception subdomains unrelated to physical activity and sport, such as school-based aspects were associated with a healthier identity. These findings should guide school based interventions to provide support in these domains in order to strengthen self-worth and identity health.     

Relevance of the listener’s motor system in recalling phrases enacted by the speaker

Memory for series of action phrases improves in listeners when speakers accompany each phrase with congruent gestures compared to when speakers stay still. Studies reveal that the listeners’ motor system, at encoding, plays a crucial role in this enactment effect. We present two experiments on gesture observation, which explored the role of the listeners’ motor system at recall. The participants listened to the phrases uttered by a speaker in two conditions in each experiment. In the gesture condition, the speaker uttered the phrases with accompanying congruent gestures, and in the no-gesture condition, the speaker stayed still while uttering the phrases. The participants were then invited, in both conditions of the experiments, to perform a motor task while recalling the phrases proffered by the speaker. The results revealed that the advantage of observing gestures on memory disappears if the listeners move at recall arms and hands (same motor effectors moved by the speaker, Experiment 1a), but not when the listeners move legs and feet (different motor effectors from those moved by the speaker, Experiment 1b). The results suggest that the listeners’ motor system is involved not only during the encoding of action phrases uttered by a speaker but also when recalling these phrases during retrieval.     

Does the A-not-B error in adult pet dogs indicate sensitivity to human communication?

Recent dog-infant comparisons have indicated that the experimenter's communicative signals in object hide-and-search tasks increase the probability of perseverative (A-not-B) errors in both species (Topál et al. 2009). These behaviourally similar results, however, might reflect different mechanisms in dogs and in children. Similar errors may occur if the motor response of retrieving the object during the A trials cannot be inhibited in the B trials or if the experimenter's movements and signals toward the A hiding place in the B trials ('sham-baiting') distract the dogs' attention. In order to test these hypotheses, we tested dogs similarly to Topál et al. (2009) but eliminated the motor search in the A trials and 'sham-baiting' in the B trials. We found that neither an inability to inhibit previously rewarded motor response nor insufficiencies in their working memory and/or attention skills can explain dogs' erroneous choices. Further, we replicated the finding that dogs have a strong tendency to commit the A-not-B error after ostensive-communicative hiding and demonstrated the crucial effect of socio-communicative cues as the A-not-B error diminishes when location B is ostensively enhanced. These findings further support the hypothesis that the dogs' A-not-B error may reflect a special sensitivity to human communicative cues. Such object-hiding and search tasks provide a typical case for how susceptibility to human social signals could (mis)lead domestic dogs.