The motor side of emotions: investigating the relationship between hemispheres, motor reactions and emotional stimuli

The aim of the present study was to analyze if the left hemisphere preferentially controls flexion responses toward positive stimuli, while the right hemisphere is specialized toward extensor responses to negative pictures. To this end, right-handed subjects had to pull or push a joystick subsequent to seeing a positive or a negative stimulus in their left or right hemifield. Flexion responses were faster for positive stimuli, while negative stimuli were associated with faster extensions responses. Overall, performance was fastest when emotional stimuli were presented to the left visual hemifield. This right hemisphere superiority was especially clear for negative stimuli, while reaction times toward positive pictures showed no hemispheric difference. We did not find any interaction between hemifield and response type. Neither was there a triple interaction between valence, hemifield and response type. We suppose that response dichotomies in humans are not as tightly linked to a hemisphere- and valence-bound reaction type as previously assumed.     

Practice makes transfer of motor skills imperfect

We investigated the practice-effects on motor skill transfer and the associated representational memory changes that occur during the within-practice and between-practice phases. In two experiments, participants produced extension–flexion movements with their dominant right arm for a limited or prolonged practice session arranged in either a single- or multi-session format. We tested the ability of participants to transfer the original pattern (extrinsic transformation) or the mirrored one (intrinsic transformation) to the non-dominant left arm, 10?min and 24?h after the practice sessions. Results showed that practice induces rapid motor skill improvements that are non-transferable irrespective of the amount of acquisition trials. Furthermore, the extrinsic component of the skill develops early and remains the dominant coding system during practice. Conversely, we found distinct between-practice memory changes: a limited practice induces an off-line development of the extrinsic component, whereas a prolonged practice session subserves the off-line development of the intrinsic component (Experiment 2). We provided further evidence that the long-term representation of the motor skill also depends on the nature of the practice session itself: the parsing of practice into multiple sessions narrows the effector-transfer capacities in comparison to a single session (Experiment 1). These findings yield theoretical and practical implications that are discussed in the context of recent motor skill learning models.     

Gaze behaviour during space perception and spatial decision making

A series of four experiments investigating gaze behavior and decision making in the context of wayfinding is reported. Participants were presented with screenshots of choice points taken in large virtual environments. Each screenshot depicted alternative path options. In Experiment 1, participants had to decide between them to find an object hidden in the environment. In Experiment 2, participants were first informed about which path option to take as if following a guided route. Subsequently, they were presented with the same images in random order and had to indicate which path option they chose during initial exposure. In Experiment 1, we demonstrate (1) that participants have a tendency to choose the path option that featured the longer line of sight, and (2) a robust gaze bias towards the eventually chosen path option. In Experiment 2, systematic differences in gaze behavior towards the alternative path options between encoding and decoding were observed. Based on data from Experiments 1 and 2 and two control experiments ensuring that fixation patterns were specific to the spatial tasks, we develop a tentative model of gaze behavior during wayfinding decision making suggesting that particular attention was paid to image areas depicting changes in the local geometry of the environments such as corners, openings, and occlusions. Together, the results suggest that gaze during a wayfinding tasks is directed toward, and can be predicted by, a subset of environmental features and that gaze bias effects are a general phenomenon of visual decision making.     

Cost–benefit and distributional analyses of accessory stimuli

Accessory stimuli (AS) are task-irrelevant events (typically an auditory tone) that speed reaction time (RT). With two conditions (AS-present, AS-absent) it is unclear whether AS-presence causes benefits or AS-absence causes costs, possibly due to the expectancy violations. The current study added a third condition where AS were absent in blocks and not expected (pure blocks); in other blocks, AS occurred with a probability of 0.5 (mixed blocks), allowing cost-benefit analysis comparing AS-absent RTs in pure and mixed blocks. Results demonstrated RTs were slower when AS were absent, regardless of whether the absence occurred in a mixed block or a pure block, suggesting AS do provide a benefit to RT. Additionally, AS-facilitation across the RT distribution was analysed using cumulative distribution frequencies and ex-Gaussian parameter estimation. Both provided converging evidence that AS-facilitation increases towards the slower end of the RT distribution. The implications for the utility of AS paradigms are discussed.     

Perfectionistic self-presentation, socially prescribed perfectionism, and suicide in youth: a test of the perfectionism social disconnection model

The role of interpersonal components of perfectionism in suicide outcomes among youth was assessed and the Perfectionism Social Disconnection Model (PSDM) was tested by determining whether the links between socially prescribed perfectionism (SPP) and perfectionistic self-presentation (PSP) and suicide outcomes are mediated by experiences of social disconnection, as indicated by social hopelessness and being bullied. PSP, trait perfectionism, suicide outcomes, and experiences of being bullied and social hopelessness were measured in 152 psychiatric outpatient children and adolescents. Correlational tests confirmed that PSP and SPP were associated with suicide outcomes and these interpersonal perfectionism components were associated significantly with bullying and social hopelessness. Support was also obtained for the PSDM. The relationship between the PSP facets, particularly nondisplay of imperfections, and suicide outcomes were mediated by being bullied. Additionally, the relationship between all interpersonal components of perfectionism and suicide risk was mediated by social hopelessness. Theoretical and clinical implications of interpersonal components of perfectionism and social disconnection in suicide outcomes for youth are discussed.     

Preventing suicide through improved training in suicide risk assessment and care: an American Association of Suicidology Task Force report addressing serious gaps in U.S. mental health training

There are twice as many suicides as homicides in the United States, and the suicide rate is rising. Suicides increased 12% between 1999 and 2009. Mental health professionals often treat suicidal patients, and suicide occurs even among patients who are seeking treatment or are currently in treatment. Despite these facts, training of most mental health professionals in the assessment and management of suicidal patients is surprisingly limited. The extant literature regarding the frequency with which mental health professionals encounter suicidal patients is reviewed, as is the prevalence of training in suicide risk assessment and management. Most importantly, six recommendations are made to address the longstanding insufficient training within the mental health professions regarding the assessment and management of suicidal patients.     

Toddlers benefit from labeling on an executive function search task

Although labeling improves executive function (EF) performance in children older than 3 years, the results from studies with younger children have been equivocal. In the current study, we assessed performance in a computerized multistep multilocation search task with older 2-year-olds. The correct search location was either (a) not marked by a familiar picture or given a distinct label, (b) marked by a familiar picture but not given a distinct label, (c) marked by a familiar picture and labeled by the experimenter, or (d) marked by a familiar picture and labeled by the participant. The results revealed that accuracy improved across conditions such that children made the fewest errors when they generated the label for the hiding location. These findings support the hierarchical competing systems model, which postulates that improved performance can be explained by more powerful representations that guide search behavior.     

An investigation of the accuracy of standardized path coefficients

Given the popular and ever-increasing use of path analytic research paradigms in the social sciences, it is desirable to conduct an investigation into the accuracy of the standardized path coefficients that are often the end-product of these paradigms. In pursuit of this goal, population parameters were preset concerning the correlations between all of the variables and their reliability coefficients. Based on these parameters, thousands of experiments were generated with varying numbers of cases (n). For each experiment, at each level of n, standard path analyses were conducted, and standardized path coefficients were obtained. These standardized path coefficients were then compared against the population path coefficients on which the simulations were based to determine their accuracy. The findings indicate mixed evidence for the accuracy of path analysis research paradigms.     

Using a sharp instrument to parse apart strategy and consistency: an evaluation of PPT and its assumptions

Potential Performance Theory (PPT) is a general theory for parsing observed performance into the underlying strategy and the consistency with which it is used. Although empirical research has supported that PPT is useful, it is desirable to have more information about the bias and standard errors of PPT findings. It also is beneficial to know the effects of violations of PPT assumptions. The authors present computer simulations that evaluate bias and standard errors at varying levels of strategy, consistency, and number of trials per participant. The simulations show that, when the assumptions are true, there is very little bias and the standard errors are low when there are moderate or large numbers of trials per participant (e.g., N=50 or N=100). But when the independence assumption is violated, PPT provides biased findings, although the bias is quite small unless the violations are large.     

Effects of electromyostimulation on knee extensors and flexors strength and steadiness in older adults

It is known that electromyostimulation (EMS) alone or superimposed over voluntary contraction (EV) can effectively improve muscle strength. However, the effect of this type of training on the ability to control force production at submaximal levels is unknown. The authors examined the effects of EV training on steadiness in force production of knee extensors and flexors in older adults. Forty participants, including 20 men and 20 women, 60-77 years of age, were randomly allocated into a control group (CG) and an electromyostimulation superimposed over voluntary contraction (EVG) group. The EVG performed 30 bilateral isometric knee extension and flexion contractions per session, 3 training sessions per week, for 6 weeks. The variations in force production, expressed in absolute (standard deviation [SD]) and relative (coefficient of variation [CV]) terms, were assessed in isometric contractions at 5%, 15% and 25% maximal voluntary contraction (MVC) levels. Results indicated that MVC increased in knee extension and flexion in EVG (p < .05) after the training; steadiness CV also improved at 15% MVC in knee flexion (p < .05) but no significant changes were found in knee extension and steadiness SD. The training-induced changes in MVC were not correlated to steadiness CV that might indicate different mechanisms underlying these adaptations.