Do equilibrium constraints modulate postural reaction when viewing imbalance?

Action observation and action execution are tightly coupled on a neurophysiological and a behavioral level, such that visually perceiving an action can contaminate simultaneous and subsequent action execution. More specifically, observing a model in postural disequilibrium was shown to induce an increase in observers' body sway. Here we reciprocally questioned the role of observers' motor system in the contagion process by comparing participants' body sway when watching displays of antero-posterior vs. lateral imbalance. Indeed, during upright standing, biomechanical constraints differ along the antero-posterior (A-P) and medio-lateral (M-L) axes; hence an impact of observers' postural constraints on the contagion response would result in different reactions to both types of stimuli. In response to the displays, we recorded greater area of center of pressure (CoP) displacement when watching forward/backward compared to left/right imbalance. In addition, after normalizing A-P and M-L CoP displacements by a control condition (fixation cross), A-P CoP path length when viewing forward imbalance tended to be higher than M-L CoP path length when viewing imbalance to the left or right. These results indicate that postural contagion is promoted when the display is compatible with observers' motor stabilization strategy which is mainly oriented along the A-P axis. In terms of clinical application, this study brings new indications for adaptation of observational training devices in rehabilitation programs.     

Verbal social primes alter motor contagion during action observation

We investigated whether prosocial and nonsocial word primes prior to action observation modify subsequent initiation and execution of the observer's own reach-to-grasp actions. Participants observed a model performing exaggeratedly curved (vertical deviation) or natural straight reaches to a vertical dowel and always performed a straight reach to a dowel themselves. Observing curved movements slowed initiation times and increased the vertical deviation of the participants’ movements. Observing curved movements enhanced vertical deviation only in the prosocial word primes condition. We suggest that social context priming can modulate initiation of movement as well as the extent of motor contagion (in this case, the extent of vertical deviation) between model and observer.     

Predictors of perceived road collision/incident risk among horse users: A survey study from Norway

Although horse users in traffic are a vulnerable road user group, traffic safety problems among them are scantly examined by previous research. The main aim of the present study was to examine the role of some demographic variables, traffic safety attitudes, and level of knowledge about rules and regulations applying to horse use in traffic for predicting perceived road collision/incident risk in a sample of horse users in Norway. An online survey was conducted to collect data from a total of 1733 horse users including horse riders and drivers of horse-drawn sulky, wagon or sled. The respondents accessed the survey via a link put to the website of the Norwegian Horse Centre, which is in contact with many different horse user environments in Norway. The majority of the respondents were female and between the ages of 18–30. A multiple regression analysis was conducted to examine the predictors of the perceived collision/incident risk involving other motor vehicles. Results showed that traffic safety attitudes among horse users were the strongest predictor of the perceived collision/incident risk. In particular, horse users reported a negative attitude towards the other road users (e.g. drivers) indicating that they perceive the other road users’ actions and approaches as the biggest source of risk in road traffic. The level of knowledge about the rules and regulations applying to horse use, especially in walking and cycling lane, was relatively low among the respondents. However, knowledge about rules and regulations did not appear as a strong predictor of the perceived collision/incident risk. Results indicate the need to increase road users, especially drivers’, awareness about the problems and needs of horse users in traffic.     

Response inhibition in motor and oculomotor conflict tasks: Different mechanisms,different dynamics?

Previous research has shown that the appearance of task-irrelevant abrupt onsets influences saccadic eye movements during visual search and may slow down manual reactions to target stimuli. Analysis of reaction time distributions in the present study offers evidence suggesting that top-down inhibition processes actively suppress oculomotor or motor responses elicited by a salient distractor, in order to resolve the conflict that arises when reflex-like and deliberate responses are in opposition. Twenty-six participants carried out a variation of the oculomotor capture task. They were instructed to respond with either a saccade toward or with a button press at the side of the hemifield in which a target color singleton appeared. A distractor stimulus could appear either in the same or in the opposite hemifield. Delta plots revealed competition between reflex-like and deliberate response activation, and highlighted selective inhibition of automatic responses: While participants generally responded more slowly in incongruent compared to congruent situations, this effect diminished and even reversed in the slowest speed quantiles. These effects were present in both the oculomotor and motor response-mode conditions.     

Rocking together: dynamics of intentional and unintentional interpersonal coordination

The current study investigated the interpersonal coordination that occurred between two people when sitting side-by-side in rocking chairs. In two experiments participant pairs rocked in chairs that had the same or different natural periods. By instructing pairs to coordinate their movements inphase or antiphase, Experiment 1 investigated whether the stable patterns of intentional interpersonal coordination were consistent with the dynamics of within person interlimb coordination. By instructing the participants to rock at their own preferred tempo, Experiment 2 investigated whether the rocking chair movements of visually coupled individuals would become unintentionally coordinated. The degree to which the participants fixated on the movements of their co-actor was also manipulated to examine whether visual focus modulates the strength of interpersonal coordination. As expected, the patterns of coordination observed in both experiments demonstrated that the intentional and unintentional interpersonal coordination of rocking chair movements is constrained by the self-organizing dynamics of a coupled oscillator system. The results of the visual focus manipulations indicate that the stability of a visual interpersonal coupling is mediated by attention and the degree to which an individual is able to detect information about a co-actor's movements.     

Motor intentionality and the case of Schneider

I argue that Merleau-Ponty’s use of the case of Schneider in his arguments for the existence of non-conconceptual and non-representational motor intentionality contains a problematic methodological ambiguity. Motor intentionality is both to be revealed by its perspicuous preservation and by its contrastive impairment in one and the same case. To resolve the resulting contradiction I suggest we emphasize the second of Merleau-Ponty’s two lines of argument. I argue that this interpretation is the one in best accordance both with Merleau-Ponty’s general methodology and with the empirical case of Schneider as it was described by Gelb and Goldstein.

Differential dynamics of spatial and non-spatial stimulus-response compatibility effects: a dual task LRP study

Choice reaction times are shorter when stimulus and response features are compatible rather than incompatible. Recent studies revealed that spatial compatibility effects in Simon tasks are strongly attenuated when there is temporal overlap with a different high-priority task. In contrast, non-spatial variants of the Simon task appear to be unaffected by task overlap. The present study used the lateralized readiness potential (LRP) within a dual task design to elucidate the dynamics underlying these differential effects for a color and a spatial variant of the Simon task. In the color version there was no sign of early response priming by irrelevant stimulus features in the LRP. The color compatibility effect was independent of task overlap and reflected in the LRP onset latency. In contrast, in the spatial version, priming by irrelevant stimulus location showed up and was mirrored by early LRP activation. Response priming and the corresponding Simon effect, however, were present only in case of little temporal overlap with the primary task. The absence of spatial compatibility effects at strong temporal overlap suggests that response conflicts due to stimulus-related priming depend on the availability of processing resources.     

道路交通标志中对称结构效应的眼动研究

本研究考察了道路交通标志中路名信息对称结构效应的眼动模式。实验采用眼动跟踪技术和视觉搜索范式,共有16名被试参加。实验结果表明：（1）在对称结构路名信息的视觉搜索中,被试的反应正确率明显优于非对称结构条件下的正确率;（2）对称结构条件下,被试的注视点和回扫次数明显较少,凝视时间明显较短;（3）在以道路交通标志为视觉搜索材料时,搜索区有无路名目标对视觉搜索绩效没有影响。可以认为：在道路交通标志中存在对称结构效应;眼动模式的差异是引起对称结构效应的认知机制。     

Aggressive driving: Do driving overconfidence and aggressive thoughts behind the wheel,drive professionals off the road?

Aggressive driving has emerged as one of the most studied behaviors in the traffic psychology context due to its association with odds of motor vehicle crashes (MVCs) and especially fatal ones. Nevertheless, behavioral (aggression) and affective (anger) aspects of aggressive driving have been deeply studied; its cognitive part hasn’t gained much attention; However, its role in understanding the process of aggression and designing interventions couldn’t be neglected. This research investigated the contribution of overconfidence (as the driver’s cognitive bias), aggressive thoughts, driver’s aggression, and risk perception in driver’s performance and the number of self-reported active accidents. The unique contribution of this study is its sample of urban bus drivers that have less been studied to date. Structural equation modeling (SEM), and mediation analysis revealed that overconfidence contributes to aggressive driving through aggressive thoughts behind the wheel. Moreover, overconfidence decreased the risk perception and driving performance of individuals, which were associated with a higher number of driver’s accidents. Besides, aggressive thoughts behind the wheel predicted physically aggressive expression and using the vehicle to express anger, which were associated with a decreased level of driving performance and an increased number of accidents. This study brings further evidence, supporting the importance of cognition in understanding and preventing aggressive driving and its adverse outcomes.     

Personality and action control: BAS Reward predicts motor control accuracy

Theoretically, the processes involved in approach motivation and action control should overlap. In both cases, a person must commit to a goal, identify a goal target, and seek to reduce discrepancies between the self and this goal target on a somewhat continuous basis. These ideas motivated three studies (total N = 253) in which personality differences in the behavioral approach system (BAS) and the behavioral inhibition system (BIS) were assessed as potential predictors of performance in an objective motor control task. People high in BAS Reward had markedly better motor control (i.e., smaller distances from targets) than people low in BAS Reward. This was true across a variety of affective priming conditions. The other components of BAS and BIS, by contrast, were inconsistent predictors. The results support both reward-based and functional perspectives of the BAS in the context of a cybernetic view of how self-regulation by approach operates.