Response inhibition and avoidance of virtual obstacles during gait in healthy young and older adults

Adjustments of preplanned steps are essential for fall avoidance and require response inhibition. Still, inhibition is rarely tested under conditions resembling daily living. We evaluated the ability of young and older adults to modify ongoing walking movements using a novel precision step inhibition (PSI) task combined with an auditory Stroop task.Healthy young (YA, n = 12) and older (OA, n = 12) adults performed the PSI task at 4 individualized difficulty levels, as a single and dual task (DT). Subjects walked on a treadmill by stepping on virtual stepping stones, unless these changed color during approach, forcing the subjects to avoid them. OA made more failures (40%) on the PSI task than YA (16%), but DT did not affect their performance. In combination with increased rates of omitted Stroop task responses, this indicates a “posture first” strategy. Yet, adding obstacles to the PSI task significantly deteriorated Stroop performance in both groups (the average Stroop composite score decreased by 13% in YA and 27% in OA). Largest deficit of OA was observed in rates of incorrect responses to incongruent Stroop stimuli (OA 35% and YA 12%), which require response inhibition. We concluded that the performance of OA suffered specifically when response inhibition was required.     

Improving general intelligence with a nutrient-based pharmacological intervention

Cognitive enhancing substances such as amphetamine and modafinil have become popular in recent years to improve acute cognitive performance particularly in environments in which enhanced cognition or intelligence is required. Nutraceutical nootropics, which are natural substances that have the ability to bring about acute or chronic changes in cognition have also been gaining popularity in a range of settings and applications including the workplace, driving and in the amelioration of age related cognitive decline. Huperzine A, Vinpocetine, Acetyl-l-carnitine, Rhodiola Rosea and Alpha-lipoic Acid are popular nutritional supplements that have shown promising benefits in improving a range of biological (e.g., blood flow, anti-inflammatory, anti-oxidant, and direct neurotransmitter effects) and cognitive processes from in vitro, animal and human clinical research. We report here the first human randomized clinical trial for cognition in which we administer a combination of Huperzine A, Vinpocetine, Acetyl-l-carnitine, R. Rosea and Alpha-lipoic acid (called Ceretrophin) vs placebo. Sixty participants (40 females and 20 males, with a mean age of 45.4 years, SD = 12.6) completed either the odd or even items from the Raven Advanced Progressive Matrices (APM) at baseline and the opposite odd or even items at week 4 after consuming either the combination nootropic or placebo. A significant study visit (time) × treatment condition interaction was found: F (1, 57) = 7.279, p = 0.009, partial η² = .113, with paired samples t-tests revealing a significant improvement in mean APM score from baseline to retest (week 4) (t(34) = ? 4.045, p < .001) for the Ceretrophin? group. Improvements in APM scores could be attributed to the active intervention over the placebo, indicating that the treatment improved general intelligence. Implications for improving our understanding of the biological basis of intelligence and pharmacologically improving human cognition are discussed.     

Autonomic impairment in Borderline Personality Disorder: A laboratory investigation

Recent research suggests that emotional dysfunction in psychiatric disorders can be reflected in autonomic abnormalities. The present study examines sympathetic and parasympathetic autonomic nervous system activity in individuals with Borderline Personality Disorder (BPD) before, during, and following a social stressor task. Data were obtained from an analogue sample of participants screening positive for BPD (n = 12) and healthy controls (n = 28). In general, BPD participants exhibited increased sympathetic activity (indexed by Cardiac Sympathetic Index, CSI; Toichi et al., 1997) and decreased parasympathetic activity (indexed by Respiratory Sinus Arrhythmia, RSA) compared to controls. During the stressful task, BPD and control participants exhibited different trajectories of sympathetic activation: estimates of sympathetic activity increased for BPD participants and decreased for controls. Furthermore, BPD participants reported the task (but not baseline or recovery phases) to be more frustrating than controls. Findings are interpreted in the context of Polyvagal theory.     

Attention lapses and behavioural microsleeps during tracking,psychomotor vigilance,and dual tasks

This study examined the incidence of attention lapses and microsleeps under contrasting levels of task complexity during three tasks: PVT, 2-D tracking and a dual task combining the two. More attention lapses per participant (median 15 vs. 3; range 1–74 vs. 0–76, p = 0.001), with the greatest increase with time spent-on-task (p = 0.002), were evident on the more cognitively-demanding dual task than on the PVT. Conversely, fewer microsleeps (median 0 vs. 0; range 0–1 vs. 0–18, p = 0.022) occurred during the more complex task compared to the tracking task. An increase in microsleep rate with time spent-on-task (p = 0.035) was evident during the tracking task but not the dual task. These results indicate that the higher cognitive load, associated with an increase in task complexity, increased the likelihood of attention lapses, while a reduction in task complexity increased the likelihood of microsleeps.     

The effects of autonomous difficulty selection on engagement,motivation, and learning in a motion-controlled video game task

This experiment investigated the relationship between motivation, engagement, and learning in a video game task. Previous studies have shown increased autonomy during practice leads to superior retention of motor skills, but it is not clear why this benefit occurs. Some studies suggest this benefit arises from increased motivation during practice; others suggest the benefit arises from better information processing. Sixty novice participants were randomly assigned to a self-controlled group, who chose the progression of difficulty during practice, or to a yoked group, who experienced the same difficulty progression but did not have choice. At the end of practice, participants completed surveys measuring intrinsic motivation and engagement. One week later, participants returned for a series of retention tests at three different difficulty levels. RM-ANCOVA (controlling for pre-test) showed that the self-controlled group had improved retention compared to the yoked group, on average, β = 46.78, 95% CI = [2.68, 90.87], p = 0.04, but this difference was only statistically significant on the moderate difficulty post-test (p = 0.004). The self-controlled group also showed greater intrinsic motivation during practice, t(58) = 2.61, p = 0.01. However, there was no evidence that individual differences in engagement (p = 0.20) or motivation (p = 0.87) were associated with learning, which was the relationship this experiment was powered to detect. These data are inconsistent with strictly motivational accounts of how autonomy benefits learning, instead suggesting the benefits of autonomy may be mediated through other mechanisms. For instance, within the information processing framework, the learning benefits may emerge from learners appropriately adjusting difficulty to maintain an appropriate level of challenge (i.e., maintaining the relationship between task demands and cognitive resources).     

A Test of the Habit-Goal Framework of Depressive Rumination and Its Relevance to Cognitive Reactivity

The aim of the present study was to test predictions derived from the habit-goal framework of depressive rumination and investigate its relevance to cognitive reactivity—another well-known vulnerability factor to depression. Formerly depressed (FD; n = 20) and never depressed (ND; n = 22) participants completed self-report measures of rumination, cognitive reactivity, and habitual characteristics of rumination (e.g., lack of awareness, control, intent). A standard mood-induction task was also used to measure cognitive reactivity and an outcome-devaluation task to measure general habit vs. goal-directed behavior control. Habitual characteristics of ruminative thoughts were greater in the FD group and were related to depressive brooding and cognitive reactivity, but not reflective pondering. Reliance on habit on the outcome-devaluation task was strongly correlated with number of depression episodes, although group differences were not observed in general habit vs. goal-directed control. Habitual characteristics of rumination (e.g., greater automaticity) may explain reactivity and persistence of negative thoughts in depression. Habitual behavior control may contribute to inflexible responding and vulnerability for depression episodes.     

The relation between empathy and offending: A meta-analysis

A meta-analysis of k = 38 studies (60 independent effect sizes), including 6631 participants, was conducted to investigate whether differences in cognitive and affective empathy exist between offenders and non-offenders. Cognitive empathy was more strongly associated with offending (d = .43) than affective empathy (d = .19). Moderator analyses revealed that various study and participant characteristics (i.e., year of publication, impact factor, age and sex of the participant, and assessment instrument) influenced the strength and direction of the association between cognitive empathy and offending. Type of assessment instrument, the number of variables on which the offender and comparison group were matched, age and sex of the participants influenced the strength of the association between affective empathy and offending.     

Sense of body ownership in patients affected by functional motor symptoms (conversion disorder)

Background and aimPatients with functional neurological symptoms are commonly seen in neurological practice. Nevertheless their aetiopathology remains unclear. We have recently shown that patients affected by functional motor symptoms (FMS) present lower interoceptive awareness and higher alexithymia levels than healthy controls. Nevertheless sense of body ownership has never been studied in FMS patients.The aim of the present study was to systematically investigate the sense of body ownership, with the rubber hand illusion (RHI) paradigm, in patients with FMS and healthy controls.Materials and methodsWe included in the study 16 patients with FMS and 18 healthy controls (HC). Patients and HC were asked to complete the Toronto Alexithymia Scale (TAS-20) and the self-consciousness scale (self-objectification questionnaire). All participants underwent the RHI paradigm: illusionary experience was measured by self-report and by proprioceptive alteration.ResultsA Mann–Whitney U test performed revealed that FMS (median = 2.11) participants embodied the rubber hand to the same extent than HC participants (median = 2.0, Z = −0.86, p > 0.05, r = −0.15). The same test revealed no significant difference in the Proprioceptive Drift experience between FMS (median = 0.0) and HC participants (median = −0.5, Z = −0.96, p > 0.05, r = −0.16).ConclusionsOur study revealed that sense of body ownership is not impaired in patients affected by FMS. This, together with the results from our previous experiment (studying the interoceptive awareness), supports the hypothesis that interoceptive awareness and sense of body ownership may be dissociated in patients with FMS.     

Functioning of peripheral Ia pathways in leg muscles of newly walking toddlers

Monosynaptic and polysynaptic spinal level reflexes in the leg muscles of infants show significant dispersion across muscles, high variability, and no change in response patterns over the first 10 months. Here we tested the hypothesized relation between early walking experience and the tuning of these responses in three primary gait muscles of participants in four subgroups: cruisers (n = 7) and toddlers with one (n = 5), two (n = 5), or three (n = 5) months of walking experience. Reflex responses in multiple Ia pathways – tendon reflex (T-reflex), vibration-induced inhibition of the T-reflex (VIM-T-reflex), and tonic vibration-induced reflex (VIR), were elicited by mechanical stimuli applied to the distal tendons of the quadriceps, gastrocnemius-soleus, and tibialis anterior of both legs. Walking skill was assessed via a GAITRite mat. Generally, walking experience seemed to be related to slowly emerging improvements and, depending on muscle tested and pathway, progress was quite varied. Amplitude and latency of reflex responses were more clearly impacted by age or leg length while the ratio or distribution pattern of reflex response among antagonist pairs of muscles was impacted by walking experience and skill. As walking experience increased, the ratio of reflex responses tended to increase for the stimulated and decrease for the antagonist reflex loops with distribution of the pattern shifting gradually toward a single type of reflex response in all tested muscles. The very slow tuning of these reflexes may underlie the many missteps and falls reported to occur during early walking and suggest that subsequent studies should continue to follow the developmental trajectory through the first year of walking experience.     

Alterations in stride-to-stride variability during walking in individuals with chronic ankle instability

The aim of this study was to evaluate stride-to-stride variability of the lower extremity during walking in individuals with and without chronic ankle instability (CAI) using a nonlinear analysis. Twenty-five participants with self-reported CAI and 27 healthy control participants volunteered for this study. Participants walked on a motor-driven treadmill for 3 min at their selected speed. Lower extremity kinematics in the sagittal and frontal planes were recorded using a passive retroreflective marker motion capture system. The temporal structure of walking variability was analyzed with sample entropy (SampEn). The CAI group produced lower SampEn values in frontal-plane ankle kinematics compared to the control group (P = .04). No significant group differences were observed for SampEn values of other kinematics (P > .05). Participants with CAI demonstrated less stride-to-stride variability of the frontal plane ankle kinematics compared to healthy controls. Decreased variability of walking patterns demonstrated by participants with CAI indicates that the presence of CAI may be associated with a less adaptable sensorimotor system to environmental changes. The altered sensorimotor function associated with CAI may be targets for clinical interventions, and it is critical to explore how interventions protocols affect sensorimotor system function.     

An Experimental Investigation of the Effect of Stress on Saving and Acquiring Behavioral Tendencies: The Role of Distress Tolerance and Negative Urgency

Stress has been implicated as a risk factor for hoarding, although past research has relied on cross-sectional and self-report designs. Using experimental methods and objective hypothetical behavioral hoarding paradigms, we investigated the direct effect of stress on in-the-moment saving and acquiring behavioral tendencies. We also evaluated whether distress tolerance (DT) and negative urgency interacted with stress to predict saving and acquiring behavioral tendencies. A sample of young adults (N = 80) completed questionnaires about DT and negative urgency. Participants were randomized to either a psychosocial stressor or nonstressful control task prior to completing two hypothetical behavioral hoarding paradigms. The discarding task asked participants to choose between saving and disposing of items. For the acquiring task, participants completed a computer-simulated shopping spree that measured items acquired. Unexpectedly, participants in the stress condition saved and acquired fewer items than those in the control condition. As hypothesized, stress interacted with DT to predict saving tendencies. The current study should be replicated in a clinical sample. Longitudinal studies are needed to further examine the long-term effect of stress on hoarding. This is the first examination of the direct effect of stress on saving and acquiring tendencies. Although some study hypotheses were not supported, several results are consistent with our predictions and suggest a complex relationship between stress and hoarding. If findings are replicated in a clinical sample, it may be that hoarding patients could benefit from treatments incorporating DT strategies.     

Searching information on the Web and Planning Fallacy: A pilot investigation of pessimistic forecasts

IntroductionAccording to Planning Fallacy, people underestimate the time required to complete a task. A review of the social, cognitive, and motivational factors that moderate Planning Fallacy suggests that variability in Web searching tasks would lead to an overestimation of retrieval time, at least when the task duration is short (about 10 minutes).ObjectiveThe goals of this pilot study are twofold: to check the accuracy of forecasts when users estimate the time required to retrieve information on the Web, and to understand users’ strategies for dealing with the Web for multipurpose documentation.MethodParticipants (n = 32) were asked how long it would take to answer four encyclopedic questions on the Web; questions were in various fields with two levels of difficulty and two types of answers (qualitative vs quantitative). We compared estimations of the time required to retrieve specific information on the Web with the actual retrieval time. Forecasts were made before and after the effective retrieval task (within-subjects design).ResultsA significant and large overestimation of the anticipated time was observed, especially for questions with a qualitative answer. The overestimation range was between 195% and 473% for mean search durations between 4.5 and 10.3 min. Task perceived difficulty was the best predictor of time anticipation (r² < 0.32). Web search self-efficacy and experience contributed slightly to the overestimation but only for easy questions.ConclusionOverestimation of the time required to complete a Web searching task (i.e. pessimistic Planning Fallacy) results from a combination of factors: short length of tasks, variability in task difficulty, and the qualitative or quantitative nature of the correct answer. Search time forecast could be used as a benchmark to improve Web usability.     

Does intra-individual variability in narration matter and for what?

Building on calls to examine intra-individual variability in personality, we examined such variability in narrative. In Study 1, participants (n = 553) provided three narratives (either self-defining, turning point, transgression, low point, or trauma memories; n = 1659 narratives). Narratives were coded for coherence, autobiographical reasoning, resolution, and emotional expression. Variability was highest for resolution, lowest for coherence, and was related to well-being, depending on narrative feature and event type. In Study 2, participants (n = 103) engaged in a ‘narrative recognition’ task to see if they could identify which narratives came from the same individual. Recognizability was substantial, but not related to variability or well-being. Results showcase the importance of addressing intra-individual variability by narrative feature and event type.     

Variability of kinematic graphomotor fluency in adults with ADHD

Although graphomotor differences and variability of performance have been observed in children with attention deficit hyperactivity disorder (ADHD), no study has investigated whether this variability manifests in the kinematic graphomotor domain in adults with ADHD. Fourteen ADHD and 20 control participants wrote a novel grapheme and common word on a digitizing tablet 30 times each, with ADHD participants counterbalanced on and off stimulant medication. Variability of graphomotor fluency was significantly greater in ADHD versus control participants only in the novel writing task, both on, F(1, 31) = 5.988, p = .020, and off stimulant medication, F(1, 32) = 8.789, p = .006. Results suggest that motor control differences in ADHD are not limited to childhood and extend into adulthood. Given sufficient additional research, variability of kinematic graphomotor fluency may increase the sensitivity/specificity of differential diagnoses and/or represent a biomarker for ADHD.     

Propulsion strategy in the gait of primary school children; the effect of age and speed

The strategy used to generate power for forward propulsion in walking and running has recently been highlighted as a marker of gait maturation and elastic energy recycling. This study investigated ankle and hip power generation as a propulsion strategy (PS) during the late stance/early swing phases of walking and running in typically developing (TD) children (15: six to nine years; 17: nine to 13 years) using three-dimensional gait analysis. Peak ankle power generation at push-off (peakA2), peak hip power generation in early swing (peakH3) and propulsion strategy (PS) [peakA2/(peakA2 + peakH3)] were calculated to provide the relative contribution of ankle power to total propulsion. Mean PS values decreased as speed increased for comfortable walking (p < 0.001), fast walking (p < 0.001) and fast running (p < 0.001), and less consistently during jogging (p = 0.054). PS varied with age (p < 0.001) only during fast walking. At any speed of fast walking, older children generated more peakA2 (p = 0.001) and less peakH3 (p = 0.001) than younger children. While the kinetics of running propulsion appear to be developed by age six years, the skills of fast walking appeared to require additional neuromuscular maturity. These findings support the concept that running is a skill that matures early for TD children.     

Skepticism: Genuine unbelief or implicit beliefs in the supernatural?

We examined whether skeptics hold implicit supernatural beliefs or implicit cognitive underpinnings of the beliefs. In study 1 (N = 57), participants read a biological or a religious story about death. The story content had no effect on skeptics’ (or believers’) afterlife beliefs. Study 2 examined the relationships between religious and non-religious paranormal beliefs and implicit views about whether supernatural and religious phenomena are imaginary or real (n1 = 33, n2 = 31). The less supernatural beliefs were endorsed the easier it was to connect “supernatural” with “imaginary”. Study 3 (N = 63) investigated whether participants’ supernatural beliefs and ontological confusions differ between speeded and non-speeded response conditions. Only non-analytical skeptics’ ontological confusions increased in speeded conditions. The results indicate that skeptics overall do not hold implicit supernatural beliefs, but that non-analytically thinking skeptics may, under supporting conditions, be prone to biases that predispose to supernatural beliefs.     

A randomized controlled trial of strong minds: A school-based mental health program combining acceptance and commitment therapy and positive psychology

To date, most early intervention programs have been based on emotion regulation strategies that address dysfunctional cognitive appraisals, problem-solving skills, and rumination. Another emotion regulation strategy, ‘acceptance’ training, has largely been overlooked. To examine the efficacy of this strategy, a school-based mental health program combining positive psychology with acceptance and commitment therapy (Strong Minds) was evaluated in a randomized controlled trial with a sample of 267 Year 10 and 11 high-school students in Sydney, Australia. Mixed models for repeated measures examined whether the program led to reductions in symptoms amongst students who commenced the program with high depression, anxiety, and stress scores, and increased wellbeing scores amongst all students. Results demonstrated that compared to controls, participants in the Strong Minds condition with elevated symptom scores (n = 63) reported significant reductions in depression (p = .047), stress (p = .01), and composite depression/anxiety symptoms (p = .02) with medium to strong effect sizes (Cohen's d = 0.53, 0.74, and 0.57, respectively). Increased wellbeing (p = .03) in the total sample and decreased anxiety scores (p = .048) for students with elevated symptoms were significant for Year 10 students with medium effect sizes (Cohen's d = 0.43 and 0.54, respectively). This study tentatively suggests that including the emotion regulation strategy of acceptance in early intervention programs may be effective in reducing symptoms and improving wellbeing in high school students. Further research to investigate the generalizability of these findings is warranted.     

Electrocortical Evidence of Enhanced Performance Monitoring in Social Anxiety

Self-focused attention is thought to be a key feature of social anxiety disorder. Yet few studies have used event-related potentials (ERPs) to examine whether socially anxious individuals display greater monitoring of their performance and attention to their errors. Similarly, only a few studies have used ERPs to examine how social anxiety is related to processing of performance feedback. Individuals with high (n = 26) and low (n = 28) levels of social anxiety completed a trial-and-error learning task. Self-focus was manipulated using false heart-rate feedback during a random subset of trials. Performance feedback was given using emotional and neutral faces in a positive context (correct = happy face; incorrect = neutral face) and negative context (correct = neutral face; incorrect = disgust face) in order to investigate biased interpretation and attention to feedback. Socially anxious subjects displayed enhanced amplitude of the ERN and CRN, suggesting greater response monitoring, and enhanced Pe amplitude, suggesting greater processing of errors relative to the low social anxiety group. No group differences were observed with respect to feedback processing. Before learning stimulus–response mappings in the negative context, the FRN was larger for self-focus compared to standard trials and marginally larger for socially anxious subjects compared to controls. These findings support cognitive models and suggest avenues for future research.     

An interfering dot-probe task facilitates the detection of mock crime memory in a reaction time (RT)-based concealed information test

The present study aimed to test the hypothesis that an interfering task in the concealed information test will help the detection of concealed memory based on participants' behavioral performance (e.g. reaction time, error rate). Here, after participants enacted a mock crime, they were introduced to a concealed information test either with or without an interfering dot-probe task. Results showed that the RT-based pure-CIT (without interference) can detect concealed memory well above chance (AUC = .88). The detection efficiency was higher (AUC = .94) in the interference-CIT based on participants' performance of the interfering task. The findings suggested that the elevation of cognitive workload could possibly increase the detection efficiency of concealed memory based on behavioral measures.     

Exploring the integration of thin-ideal internalization and self-objectification in the prevention of eating disorders

Analyses of thin-ideal internalization and self-objectification were conducted within the context of a cognitive dissonance based eating disorder prevention program implemented in an undergraduate sorority. Participants completed self-report assessments at baseline (n = 177), post-intervention (n = 169), 5-month (n = 159), and 1-year follow-up (n = 105). Cross-sectional path analysis indicated that thin-ideal internalization and self-objectification predict each other and both predict body dissatisfaction, which in turn, predicts eating disorder symptoms. A longitudinal examination conducted using hierarchical linear modeling indicated that participants showed significant reductions in thin-ideal internalization, self-objectification, body dissatisfaction, and eating disorder symptoms after participating in the prevention program. Reductions of symptoms were maintained 1-year post-intervention, with the exception of self-objectification, which was significantly reduced up to 5-months post-intervention. Collectively, results suggest that targeting both thin-ideal internalization and self-objectification simultaneously within eating disorder prevention programs could increase the reduction of eating disorder symptoms.