Inter-individual variability of forces and modular muscle coordination in cycling: A study on untrained subjects

The aim of this study was to investigate the muscle coordination underlying pedaling in untrained subjects by using the muscle synergies paradigm, and to connect it with the inter-individual variability of EMG patterns and applied forces. Nine subjects performed a pedaling exercise on a cycle-simulator. Applied forces were recorded by means of instrumented pedals able to measure two force components. EMG signals were recorded from eight muscles of the dominant leg, and Nonnegative Matrix Factorization was applied to extract muscle synergy vectors W and time-varying activation coefficients H. Inter-individual variability was assessed for EMG patterns, force profiles, and H. Four modules were sufficient to reconstruct the muscle activation repertoire for all the subjects (variance accounted for >90% for each muscle). These modules were found to be highly similar between subjects in terms of W (mean r = .89), while most of the variability in force profiles and EMG patterns was reflected, in the muscle synergy structure, in the variability of H. These four modules have a functional interpretation when related to force distribution along the pedaling cycle, and the structure of W is shared with that present in human walking, suggesting the existence of a modular motor control in humans.     

Auditory instructional cues benefit unimanual and bimanual drawing in Parkinson's disease patients

The present study investigated performance of unimanual and bimanual anti-phase and in-phase upper limb line drawing using three different types of cues. Fifteen Parkinson’s disease (PD) patients, 15 elderly, and 15 young adults drew lines away from and towards their body on a tabletop every 1000 ms for 30 s under three different cueing conditions: (1) verbal (‘up’, ‘down’); (2) auditory (high tone, low tone); (3) visual (target line switched from top to bottom). PD patients had larger and more variable amplitudes which may be related to the finding that they also produced more curvilinear movements than young and elderly adults. Consistent with previous research, when compared to the elderly and young adult group PD patients produced a mean relative phase which deviated more from the instructed coordination modes and they showed larger variability of relative phase in bimanual coordination, especially in anti-phase conditions. For all groups, auditory and verbal cues resulted in lower coefficient of variance of cycle time, lower variability of amplitude and lower variability of relative phase than visual cues. The benefit of auditory cues may be related to the timing nature of the task or factors related to the auditory cues (e.g., reduced attentional demands, more kinesthetic focus).     

Inter-limb coordination and control in boys with and without DCD in ball catching

The purpose of the study was to examine the nature of inter-limb coordination and control, exhibited by ten boys with (M = 10.5 years, SD = 1.0) and without Developmental Coordination Disorder (DCD), in a ball catching task across different ball speeds. In line with the predictions of coordinated structure theory boys who were typically developing preserved strong and effective temporal relations when catching balls in baseline and fast conditions. Boys with DCD exhibited temporal symmetry in baseline but not in fast attempts, where the decoupling was uniformed across the group, coinciding with failures on ≥ 50% of the attempts. In terms of stability, no differences in intra-individual variability were observed between the groups. The analysis of spatial and temporal adaptations showed that boys who were typically developing, in essence, covered the same “ground” by decreasing their movement time. The opposite was true for boys with DCD who contacted the ball closer to the body, while failing to adapt the velocity of their hands. Taken together, both groups exhibited strong and stable coordinative relations, in a steady-state but not in a fast condition, where all boys with DCD failed to preserve the desired symmetry. This decoupling also coincided with different and less effective spatio-temporal adaptations at the effector level. Thus, it appears that movement control, hence flexibility of their synergistic relations, represents a movement limiter for boys with DCD who exhibit specific balls skills issues, at inter-limb level of organization. It should be noted, however, that large intra-group variance observed across some variables warrants caution when interpreting the aggregate data.     

Reinforcement sensitivity theory as a predictor of senior-executive performance

This paper develops and tests links between the reinforcement sensitivity theory of personality and senior-executive job performance, hypothesising that the theory’s personality traits, known as ‘BIS’ and ‘BAS’, will interact to predict performance. 167 chief and second-tier executives completed Carver and White’s (1994)BIS/BAS Scales, and had their overall performance rated by a superior or peer using four items. Structural equation modeling showed that while BAS has no main effect and BIS has a marginally significant effect on performance (p = 0.07), BIS and BAS interact to predict performance (p = 0.01), the optimal scenario being a combination of high BAS and low BIS. These results show the importance of testing traits’ interactions in applied personality research.     

Individual differences and propensity to engage with in-vehicle distractions - A self-report survey

Ratings of severity and frequency of engagement with distracting driver behaviours are reported in this paper. Survey data were collected using an anonymous online questionnaire. Four hundred eighty-two respondents contributed to the survey during a 2 month data collection period. Results indicate that the three behaviours rated as most distracting when driving were (i) writing text messages (41%), (ii) reading text messages (62%), and (iii) using a cellular telephone hand-held (52%). The three most frequently reported distracting behaviours that resulted in accidents were (i) ‘interaction with child passengers’ 2.1% (near misses = 7.5%), (ii) both, route guidance destination entry with 2% (near misses = 2.8%) and use of an ‘… add-on media device, e.g., an iPod’ with 2% (near misses = 3.9%), and (iii) the three items ‘reading a text message’, ‘following advice from a route guidance system’, and ‘interaction with pets’, all with 1.7% of respondents reporting an accident when undertaking the activity (with 6.5%, 3%, and 2.2% respectively for near misses). Two hierarchical regression models were explored. The first introducing personal factors, i.e., age, extraversion, agreeableness, conscientiousness, emotional stability and intellect (R² = 0.131, p < 0.001). The second controlled for variables in the first model and introduced driver-related variables, mileage, penalty points, and frequency of accidents with assumed responsibility (R² = 0.253, p < 0.001). This model identified age, extraversion, mileage, penalty points and accidents all to be significant predictors of engagement with unnecessary distractions. The data presents a picture of widespread awareness of, and engagement with, distracting behaviours by drivers in the United Kingdom. Findings from the hierarchical regressions suggest scope may exist to mediate the levels of distracting behaviours by exploring individual differences and driving styles.     

The accuracy of ‘haptically’ measured geographical slant perception

In two recent issues of Acta, the widely accepted view of Proffitt (2006), that ‘haptic’ measures of perceived geographical slant are generally accurate, and dissociated from explicit overestimates, came under intense scrutiny (Durgin, Hajnal, Li, Tonge, and Stigliani, 2010; 2011). Durgin and colleagues' challenge to this account centred on the claim that Proffitt's haptic’ measure of geographical slant, the palm-board, may be accidently accurate due to restricted movements available at the wrist. Two experiments reported here compare the accuracy of Proffitt's palm-board with an alternative measure of geographical slant perception, the Palm-Controlled Inclinometer (PCI), which allows participants to use wrist, elbow and shoulder movements to match slant with their hand. Participants (N = 320) made slant judgements using both measures, across five hills and five staircases with 32 participants for each stimulus angle (4.5°–31°). Results for the palm-board replicated those of Proffitt and co-workers, overestimation at shallow angles (≤ 14°), contrasted with underestimation at steeper angles (≥ 23°), whereas estimates made using the PCI had a greater degree of accuracy for steeper slopes. A follow-up experiment tested the accuracy of the palm-board and PCI for surfaces in near space to repeat the design of Durgin et al. (2010, experiment 1). Participants (N = 20) used the palm-board and PCI to judge the angle of slanted blocks (25°, 30°). As with traversable slopes, PCI judgements did not differ from the actual angle of the blocks whereas the palm-board measure underestimated. ‘Haptic’ measures of geographical slant perception can be accurate for relatively steep slopes, in both near and far space.     

A kinematic approach to the conceptual representations of this and that

The Italian demonstrative pronouns questo/a (‘this_[mas/fem]’) and quello/a (‘that_[mas/fem]’) implicitly convey information about objects’ distance with respect to the speaker. Our study investigated the referents of questo/a (‘this_[mas/fem]’) and quello/a (‘that_[mas/fem]’) by analysing their influence on reach-to-grasp actions towards objects located near to (12 cm) or far from (30 cm) the participant. Upon acoustic instruction containing one or the other pronoun, participants had to reach for and grasp a target object. Results showed an effect of pronoun on movement planning. When the object was in the far position, reaction times were faster for the congruent pronoun quello/a, whereas when it was in the near position they were faster for the congruent pronoun questo/a. Interactions between implied and real target distance suggest that the conceptual spaces of questo/a and quello/a do not map onto a strict distinction between peripersonal and extrapersonal space.     

Inter-individual and intra-individual variability of the N2 component: On reliability and signal-to-noise ratio

The nogo N2 component, an anterior negative peak supposed to be generated in the anterior cingulate cortex, has been used as an indicator of conflict monitoring and response conflict in basic and clinical research. Here, we investigate the reliability and the signal-to-noise ratio (SNR) of inter-individual differences of the N2 amplitudes as well as of intra-individual standard deviations of N2 amplitudes. Effects of the number of nogo epochs, type of summary measure (peak vs. average amplitude), and filter cut-offs (1–12 Hz vs. 1–30 Hz) are investigated. A sample of N = 32 participants, performed a go/nogo task. Excellent Cronbach’s alpha coefficients (?.90) were obtained for the fronto-central average N2 amplitude at 40 nogo epochs and for the peak N2 amplitude at 60 nogo epochs. The SNR was higher for the average nogo N2 amplitude compared to the peak N2 amplitude. Split-half reliability coefficients of the intra-individual standard deviation of the nogo N2 amplitudes were at least moderate. Based on these results we provide suggestions for a reliable N2 measurement. Moreover, although intra-individual variability has often been conceived as noise the present findings support the idea that intra-individual N2 variability incorporates systematic variance.     

To think or not to think,that is the question: Individual differences in suppression and rebound effects in autobiographical memory

Two studies explored the effects of forget instructions on autobiographical memory at immediate test and following delays of either 12–13 months, or 3–4 months. Using the Autobiographical Think/No-Think procedure (cf., Noreen & MacLeod, 2013), 24 never-depressed participants (Study 1) first generated 12 positive and 12 negative autobiographical memories and associated cues. Participants were then asked to recall the memory associated with some of the cues (i.e., ‘think’ condition), or to avoid saying or thinking about the memory associated with other cues (i.e., ‘no-think’ condition). Participants were then asked to recall the memories associated with all the cues at immediate test and following a delay of 12–13 months. Participants were found to be successful at forgetting both positive and negative autobiographical memories following ‘no-think’ instructions at immediate test but this forgetting effect did not persist following a 12–13 month delay. This pattern of remembering and forgetting was replicated in a second study (using 27 never-depressed participants) following a 3–4 month delay. Participants who had been less successful at forgetting ‘no-think’ memories at immediate test, were more likely to show rebound effects for those memories following a delay compared to memories which received neither ‘think’ nor ‘no-think’ instructions. Individual differences in inhibitory control and the efficacy of potential therapeutic interventions of ‘no-think’ instructions are considered.     

Degrading phonetic information affects matching of audiovisual speech in adults,but not in infants

Infants and adults are well able to match auditory and visual speech, but the cues on which they rely (viz. temporal, phonetic and energetic correspondence in the auditory and visual speech streams) may differ. Here we assessed the relative contribution of the different cues using sine-wave speech (SWS). Adults (N = 52) and infants (N = 34, age ranged in between 5 and 15 months) matched 2 trisyllabic speech sounds (‘kalisu’ and ‘mufapi’), either natural or SWS, with visual speech information. On each trial, adults saw two articulating faces and matched a sound to one of these, while infants were presented the same stimuli in a preferential looking paradigm. Adults’ performance was almost flawless with natural speech, but was significantly less accurate with SWS. In contrast, infants matched the sound to the articulating face equally well for natural speech and SWS. These results suggest that infants rely to a lesser extent on phonetic cues than adults do to match audio to visual speech. This is in line with the notion that the ability to extract phonetic information from the visual signal increases during development, and suggests that phonetic knowledge might not be the basis for early audiovisual correspondence detection in speech.     

Are social networking profiles reliable indicators of sensational interests?

Sensational interests are sometimes reported on the personal profiles of social networking web sites such as Facebook. Can these reports be validated against established psychometric tools used by forensic psychologists? Given that web sites and personal profiles can be used as evidence of a person’s ‘character’ in legal contexts, evaluating their reliability and validity is important. This study evaluated the reliability of extracting data from the interests and activities sections of Facebook profiles, linking them to general personality and Sensational Interests Questionnaire (SIQ) scores. Data from 694 user profiles (N = 352 males) were linked to the Big Five personality traits, age, and educational attainment. Three independent raters coded the number of sensational topics reported by a user in each section. In Poisson regression analyses, higher SIQ Violent Occultism scores predicted a larger count of sensational interests, and sensational activities in males only. Higher SIQ Militarism scores predicted a larger number of sensational interests in males, but a smaller number in females. Although the number of sensational interests reported by social networking users on their personal profiles is potentially informative, further research should investigate gender differences, and why females with greater Militarism scores are less likely to report what these specific interests are.     

Learning and career specialty preferences of medical school applicants

The present research examined relationships among medical school applicants’ preferred approaches to learning, methods of instruction, and specialty areas (n = 912). Based on confidential responses to a progressive series of paired comparisons, applicants’ preferences for lecture (L), self-study (SS), group discussion (GD), and computers (C) were assessed across three dimensions: (1) comfort; (2) effectiveness; and (3) interest. Using cluster analysis to generate four instructional “profiles,” participants’ comparative preferences for self-study/lecture versus group discussion/computers (+SS, L/−GD, C) were positively associated with interests in surgery and neurology, whereas opposing preferences (+GD, C/−L, SS) corresponded with the practice of family medicine. Using a matriculant subset (N = 160), analyses indicated that these relationships remained after controlling for sex and psychological type.     

Self-perceived employability: Construction and initial validation of a scale for university students

This paper reports the development of a research instrument to examine the expectations and self-perceptions of employability of business undergraduates (bachelor degree students) in three UK universities, and examines relationships with other measures. The scale was found to have a satisfactory internal reliability coefficient for an untested measure (α = .75) and had discriminant validity from other new measures such as university commitment. ‘Internal’ and ‘external’ dimensions were identified, the latter relating to the perceptions of the strength of the university brand, the state of the external labour market, and the demand for the degree subject. Perceptions of future employability were surprisingly modest, notably for those in arguably the strongest position, suggesting that these self-perceptions may be a product of relative societal expectations, consistent with positional conflict theory.     

Effect of Analogy Instructions with an Internal Focus on Learning a Complex Motor Skill

This study examined the effects of an analogy in learning breaststroke swimming. Two groups of participants had 20 lessons on how to increase their stroke length. The participants in the experimental condition received an analogy with an internal focus of attention. Inter-limb coordination showed qualitative changes in this group: a greater increase in swimming efficiency (i.e., a coordination closer to anti-phase [?50° before learning and ?125° after] and a 10% decrease in the time spent in-phase). The findings showed that an internal focus of attention induced by analogy could be beneficial in improving the quality of inter-limb swimming coordination.     

Lower muscle co-contraction in flutter kicking for competitive swimmers

The purpose of this study was to examine the difference in muscle activation pattern and co-contraction of the rectus and biceps femoris in flutter-kick swimming between competitive and recreational swimmers, to better understand the mechanism of repetitive kicking movements during swimming. Ten competitive and 10 recreational swimmers swam using flutter kicks at three different velocities (100%, 90%, and 80% of their maximal velocity) in a swimming flume. Surface electromyographic signals (EMG) were obtained from the rectus (RF) and biceps femoris (BF), and lower limb kinematic data were obtained at the same time. The beginning and ending of one kick cycle was defined as when the right lateral malleolus reached its highest position in the vertical axis. The offset timing of muscle activation of RF in the recreational swimmers was significantly later at all velocities than in the competitive swimmers (47–48% and 26–33% of kick time of one cycle for recreational and competitive swimmers, respectively), although the kinematic data and other activation timing of RF and BF did not differ between groups. A higher integrated EMG of RF during hip extension and knee extension induced a higher level of muscle co-contraction between RF and BF in the recreational swimmers. These results suggest that long-term competitive swimming training can induce an effective muscle activation pattern in the upper legs.     

Comparing the influence of directly vs. indirectly encountered post-event misinformation on eyewitness remembering

Some research has found a stronger influence of directly (face-to-face; co-witness; ‘social’) vs. indirectly (through written reports, ‘non-social’) encountered post-event misinformation on eyewitness memory reports, whereas other research finds no (big) difference. We argue and demonstrate that a crucial but so far neglected variable underlying this difference is memory for the misleading information itself. In a study with N = 120 participants who encountered misinformation directly or indirectly, we found misinformation retention (as assessed in a separate test) to be positively associated with a broad range of misinformation effects. Influence type (direct vs. indirect), however, did not moderate the misinformation effect in terms of memory for original details, and misinformation endorsement was even weaker in the direct influence condition. In our view, these findings reflect differential conversion of retained misinformation into test performance. Other than this, influence type had essentially no effects on remembering; nor did an additional post-warning manipulation.     

An especial skill: Support for a learned parameters hypothesis

We tested the ‘learned parameters’ hypothesis as an explanation of the ‘especial skill effect’. Outcome attainment and movement kinematics were recorded for 10 expert and 10 novice players performing basketball free-throw shots at five distances (11-19 ft) with a regular and heavy weight basketball. As predicted, experts performed better than expected relative to the regression equation at the 15 ft, free-throw line with the regular basketball, supporting the ‘especial skill effect’. This effect was not present for the experts when shooting with the heavy ball. Novices did not show an advantage at the free-throw line when performing with either ball. Although the outcome attainment scores support the ‘learned parameters’ hypotheses, kinematic analysis failed to identify differences in the movement pattern for the especial skill, suggesting that these skills (i.e., shooting at different distances) are not governed by separate motor programs.     

Syntactic reconstruction and reanalysis,semantic dead ends,and prefrontal cortex

The left inferior frontal gyrus (LIFG) is crucially has been found to be involved in syntactic processing of various kinds. This study investigates the cortical effects of two types of syntactic processes: (i) Reconstruction in ellipsis (recovery of left-out material given by context, More people have been to Paris than […] to Oslo), using pseudo-elliptical structures (‘dead ends’) as control (More people have been to Paris than I have). (ii) Reanalysis in the face of structural ambiguity in syntactic ‘garden paths’, where the parser initially assigns an incorrect structure and is forced to reanalyze. Reanalysis and reconstruction require additional syntactic processing and were predicted to increase activation in areas otherwise involved in structural computation: LIFG (BA 44, 45), premotor BA 6, and posterior temporal BA 21, 22. This was borne out. The results showed an interaction effect of the types of construction in all three areas reflecting syntactic processing.     

Thermosensory reversal effect quantified

At room temperature, some materials feel colder than others due to differences in thermal conductivity, heat capacity and geometry. When the ambient temperature is well above skin temperature, the roles of ‘cold’ and ‘warm’ materials are reversed. In this paper, this effect is quantified by measuring discrimination thresholds for subjective coldness at different ambient temperatures using stimuli of different thicknesses. The reversal point was found to be at 34 °C, somewhat above skin temperature. At this reversal point, discrimination is quite impossible. At room temperature, subjects were able to discriminate between stimuli of different thickness based on subjective coldness, showing that the sense of touch, unlike vision, can penetrate solid objects. Furthermore, somewhat surprisingly, at ambient temperatures well below normal room temperature, discrimination is worse than at room temperature.