Visual cues two-steps ahead are adequate to grasp an object while walking without compromising stability

In our prior studies, participants walked and grasped a dowel using an anticipatory mode of control. However, it is unknown how this combined task would change in a less predictable environment. We investigated the online control aspects involved in the combined task of walking and grasping under different coordination patterns between upper- and lower-limbs in young adults. Fifteen young adults walked and grasped a dowel under several experimental conditions combining the instant of visual cue appearance and coordination pattern of upper and lower limbs used to grasp the dowel. Visual cues provided two steps ahead or earlier were enough for executing the combined task of walking and prehension appropriately. Visual cues provided within this window impacted both walking stability and the execution of the prehension movement. Although an ipsilateral arm-leg coordination pattern increased mediolateral stability, a contralateral pattern significantly decreased mediolateral center of mass stability when the visual cue appeared one-step before grasping the object. These results imply that acquiring information to plan the combined task of walking and reaching for an object two steps ahead allows the maintenance of the general movement characteristics present when the decision to reach out for the object is defined two or more steps ahead. These results indicate that the prehension movement is initiated well before heel contact on that side when given sufficient planning time, but that a disruption of the natural arm-leg coordination dynamics emerges to accomplish the task when the cue is provided one step before the object.     

Mechanical efficiency and metabolic cost as measures of learning a novel gross motor task

"Efficiency, " or economy of movement with respect to energy expended in achieving the goal of the task, is implicit in many definitions of skilled performance. This study examined changes in mechanical efficiency and transport efficiency on a novel gross motor skill. The subjects were 5 physically fit adult males who were asked to perform 20 3-min trials walking on hands and feet (crawling) on a motor-driven treadmill at constant speed (0.76 m/s). Transport efficiency, the metabolic cost of transporting the body mass a given distance at constant speed, improved significantly over practice trials. Mechanical efficiency, derived from the mechanical power output of individual body segments, showed an overall improvement of 13.7% by the last day of practice. Even though this improvement was not statistically significant it appears to be greater than that expected due to physiological training effects. The efficiency measures correlated significantly with changes in limb kinematics. It was concluded that with practice subjects tailored their movement pattern to produce energy efficient adaptations to task constraints. These findings provide empirical support for theoretical perspectives that have emphasized biological principles in the organization of motor coordination and control.     

Mechanical Efficiency and Metabolic Cost as Measures of Learning a Novel Gross Motor Task

“Efficiency,” or economy of movement with respect to energy expended in achieving the goal of the task, is implicit in many definitions of skilled performance. This study examined changes in mechanical efficiency and transport efficiency on a novel gross motor skill. The subjects were 5 physically fit adult males who were asked to perform 20 3-min trials walking on hands and feet (crawling) on a motor-driven treadmill at constant speed (0.76 mis). Transport efficiency, the metabolic cost of transporting the body mass a given distance at constant speed, improved significantly over practice trials. Mechanical efficiency, derived from the mechanical power output of individual body segments, showed an overall improvement of 13.7% by the last day of practice. Even though this improvement was not statistically significant it appears to be greater than that expected due to physiological training effects. The efficiency measures correlated significantly with changes in limb kinematics. It was concluded that with practice subjects tailored their movement pattern to produce energy efficient adaptations to task constraints. These findings provide empirical support for theoretical perspectives that have emphasized biological principles in the organization of motor coordination and control.     

The influence of visual flow and perceptual load on locomotion speed

Visual flow is used to perceive and regulate movement speed during locomotion. We assessed the extent to which variation in flow from the ground plane, arising from static visual textures, influences locomotion speed under conditions of concurrent perceptual load. In two experiments, participants walked over a 12-m projected walkway that consisted of stripes that were oriented orthogonal to the walking direction. In the critical conditions, the frequency of the stripes increased or decreased. We observed small, but consistent effects on walking speed, so that participants were walking slower when the frequency increased compared to when the frequency decreased. This basic effect suggests that participants interpreted the change in visual flow in these conditions as at least partly due to a change in their own movement speed, and counteracted such a change by speeding up or slowing down. Critically, these effects were magnified under conditions of low perceptual load and a locus of attention near the ground plane. Our findings suggest that the contribution of vision in the control of ongoing locomotion is relatively fluid and dependent on ongoing perceptual (and perhaps more generally cognitive) task demands.     

Nietzsche and drawing near to the personalities of the pre-Platonic Greeks

This essay focuses on and attempts to uncover the truly radical character of Nietzsche’s early “philological” work, specifically asking after the benefit he claims the study of classical culture should have for our present, late-modern historical moment. Taking up his study of the Pre-Platonic thinkers in 1873’s Philosophie im tragischen Zeitalter der Griechen, the first section analyzes Nietzsche’s statement that history’s principle task is the uncovering of Persönlichkeiten. I argue that it is not at all the subjective character of a psychologized individual that Nietzsche has in mind, but rather the moment of persönliche Stimmung or ‘being attuned’ to the world, which grounds and gives rise to thinking. In the second section, I show that the phusis or ‘nature’ to which the thinker is exposed in this attunement is comparable to the tension between the Dionysian and Apollonian natural forces in tragic poetry, as Nietzsche understands it. This dynamic conception of phusis does not provide a metaphysical substrate or an objectively real ground to which we might return via that Greeks, but is rather essentially phenomenal, i.e. it is nothing other than the movement into and out of appearance, which always entails and requires its reception by the human being to whom it appears. In the final section of the essay, this origin proves for Nietzsche not to be located in a distant past moment. Rather, it is the abyssal origin of the tradition that is always already effective in our present moment, informing our contemporary conceptions of our world and ourselves.     

The role of crawling and walking experience in infant spatial memory

This research explored infants' use of place learning and cue learning in a locomotor task across the transition from crawling to walking. Novice and expert crawling and walking infants were observed in a novel locomotor task-finding a hidden goal location in a large space. In Experiment 1, infants were tested with distal landmarks. Infants with fewer than 6 weeks of experience, either crawling or walking, could not find the goal location. All infants with more locomotor experience were more successful. Learning did not transfer across the transition to walking. In Experiment 2, novice and expert crawlers and walkers were tested with a direct landmark. Again, novice crawlers and walkers with fewer than 6 weeks of experience could not find the goal, whereas those with more experience could. Taken together, these findings suggest that infants' spatial learning is inextricably linked to mode of locomotion.     

The Goal Circuit Model: A Hierarchical Multi‐Route Model of the Acquisition and Control of Routine Sequential Action in Humans

Human control of action in routine situations involves a flexible interplay between (a) task‐dependent serial ordering constraints; (b) top‐down, or intentional, control processes; and (c) bottom‐up, or environmentally triggered, affordances. In addition, the interaction between these influences is modulated by learning mechanisms that, over time, appear to reduce the need for top‐down control processes while still allowing those processes to intervene at any point if necessary or if desired. We present a model of the acquisition and control of goal‐directed action that goes beyond existing models by operationalizing an interface between two putative systems—a routine and a non‐routine system—thereby demonstrating how explicitly represented goals can interact with the emergent task representations that develop through learning in the routine system. The gradual emergence of task representations offers an explanation for the transfer of control with experience from the non‐routine goal‐based system to the routine system. At the same time it allows action selection to be sensitive both to environmental triggers and to biasing from multiple levels within the goal system.     

Priming the ant or the grasshopper in people's mind: How regulatory mode affects inter‐temporal choices

The present study examined the influence of two regulatory mode concerns—a locomotion concern with movement from state to state and an assessment concern with making comparisons—on choices between immediate and delayed (from 2 to 6 weeks) money rewards. Regulatory mode orientation was induced by means of a priming procedure. We predicted that the choices in the assessment condition would be less impulsive and more far‐sighted than those in the locomotion condition. After taking into account the effects of amount of early reward, length of delay and increase in delayed reward—all of which were in the direction of previous studies—this regulatory mode prediction was supported. Our findings suggest that it might be possible to induce more far‐sighted (or economically rational) inter‐temporal choices by means of instructions that induce an assessment orientation independent of stable inter‐individual differences in discount rate. Copyright © 2009 John Wiley & Sons, Ltd.     

Topological assessment of gait synchronisation in overground walking groups

Walking is one of the fundamental forms of human gross motor activity in which spatiotemporal movement coordination can occur. While considerable body of evidence already exists on pedestrian movement coordination while walking in pairs, little is known about gait control while walking in more complex topological arrangements. To this end, this study provides some of the first evidence of spontaneous gait synchronisation while walking in a group. Nine subjects covered the total distance of 40 km at different speeds while assembled in a three-by-three formation. Two experimental protocols were applied in which the subjects were either not specifically asked to or specifically asked to synchronise their gait. To obtain results representative from the point of view of gait control, the movement coordination was quantified using the indirectly measured vertical component of ground reaction force, based on output from a network of wireless motion monitors. Bivariate phase difference analysis was conducted using wavelet transform, synchronisation strength measures derived from Shannon entropy, and circular statistics. A fundamental relationship describing the influence of the group walking speed on individuals’ pacing frequency was established, showing a positive correlation different from that previously reported for walking in solitude. A positive correlation was found between the average synchronisation strength within a group and group’s walking speed. The most persistent coordination patterns were identified for pedestrians walking front-to-back and side-by-side. Overall, the spontaneous gait synchronisation while walking in a group is relatively weak, well below the levels reported for walking in pairs.     

个体及同伴调节聚焦对目标追求的影响

探讨个体与同伴的调节聚焦对目标追求的影响及感知相似性在其中的作用。回归分析显示,个体促进聚焦×同伴促进聚焦交互项显著预测同伴作用评价、求助意愿及动机水平,简单斜率分析表明,同伴为高促进聚焦时个体促进聚焦的积极效应更明显。中介分析表明,感知相似性是个体促进聚焦×同伴促进聚焦交互项与同伴作用评价、求助意愿之间关系的中介变量。总的来说,同伴调节聚焦能调节个体调节聚焦与目标追求的关系,且这一作用部分受到感知相似性的中介。     

Reproducibility and a unifying explanation: Lessons from the shape bias

The goal of science is to advance our understanding of particular phenomena. However, in the field of development, the phenomena of interest are complex, multifaceted, and change over time. Here, we use three decades of research on the shape bias to argue that while replication is clearly an important part of the scientific process, integration across the findings of many studies that include variations in procedure is also critical to create a coherent understanding of the thoughts and behaviors of young children. The “shape bias,” or the tendency to generalize a novel label to novel objects of the same shape, is a reliable and robust behavioral finding and has been shown to predict future vocabulary growth and possible language disorders. Despite the robustness of the phenomenon, the way in which the shape bias is defined and tested has varied across studies and laboratories. The current review argues that differences in performance that come from even seemingly minor changes to the participants or task can offer critical insight to underlying mechanisms, and that working to incorporate data from multiple labs is an important way to reveal how task variation and a child’s individual pathway creates behavior—a key issue for understanding developmental phenomena.     

The study of locomotor pointing in virtual reality: The validation of a test set-up

The goal of this experiment was to validate an experimental set-up for studying locomotor pointing. The specific and also original element of this set-up was the interactive nature of virtual reality and movement production. This interaction was achieved through the coupling of a treadmill and a Silicon Graphics system. This latter system generated on a screen (3 × 2.3 m) an environmental array that moved according to the action produced by subjects on a treadmill. The task was to place either foot on a spatial target that appeared on the floor in front of the subject’s displacement trajectory. We analyzed the step length patterns of subjects approaching these targets, along with the current target-subject relationship. The results are in agreement with aperception-action coupling type of control mechanism that operates continuously as the subject approaches the desired target. Apparently, these findings mirror observations of real-life locomotion, indicating that the present set-up provides a valid and useful tool for examining human locomotion.     

Walking with avatars: Gait-related visual information for following a virtual leader

Dynamic situations, such as interactive sports or walking on a busy street, impose high demands on a person’s ability to interact with (others in) its environment (i.e., ‘interact-ability’). The current study examined how distance regulation, a fundamental component of these interactions, is mediated by different sources of visual information. Participants were presented with a back and forwards moving virtual leader, which they had to follow by walking back and forwards themselves. We presented the leader in several appearances that differed in the presence of segmental (i.e., relative movements of body segments), cadence-related (i.e., sway and bounce), and global (i.e., optical expansion-compression) information. Results indicated that removing segmental motion information from the virtual leader significantly deteriorated both temporal synchronization and spatial accuracy of the follower to the leader, especially when the movement path of the leader was less regular/predictable. However, no difference was found between cadence-related and global motion information appearances. We argue that regulating distance with others effectively requires a versatile attunement to segmental and global motion information depending on the specific task demands. The results further support the notion that detection of especially segmental information allows for more timely ‘anticipatory’ tuning to another person’s locomotor movements and intentions.     

Self-denial and the role of intentions in the attribution of agency

The ability to distinguish between our own actions and those of an external agent is a fundamental component of normal human social interaction. Both low- and high-level mechanisms are thought to contribute to the sense of movement agency, but the contribution of each is yet to be fully understood. By applying small and incremental perturbations to realistic visual feedback of the limb, the influence of high-level action intentions and low-level motor predictive mechanisms were dissociated in two experiments. In the first, participants were induced to claim agency over movements that were subject to large perturbations and to deny agency over self-produced unperturbed movements despite the application of motor corrections by low-level mechanisms. A control experiment confirmed that if reaches met with their intended goal then they were more likely to be attributed to the agent, regardless of the discrepancy between the actual and seen positions of the limb.     

Husserl and queer theory

In spite of a history wherein queer theory has openly rejected phenomenology, phenomenology has gained increasing interest amongst queer theorists. However, Husserl’s phenomenology is often marginalized in attempts to integrate queer theory with phenomenology, and when Husserl is addressed specifically, his work is often treated superficially or even misrepresented. Given this, my first goal is to demonstrate how Husserl’s work is already open to positions considered fundamental to queer theory, and that Husserl is often explicitly arguing for these positions himself. In doing so, I wish to show that Husserl’s phenomenology is well fitted for complementary engagement with queer theory. My second goal is to work through some ways in which Husserl’s phenomenology and queer theory can work together in detail to accomplish shared theoretical goals. Although this will not be a full-blown analysis—which would exceed the parameters of this article—my hope is to provide a certain amount of in depth work that can then assist further analyses that combine these methods.     

Age-related changes of arm movements in dual task condition when walking on different surfaces

The purpose of this study was to investigate whether the dual task paradigm would influence arm movements during walking. Furthermore, we examined the effects of different walking surfaces on arm movements while performing dual tasks. The effects of age and gender were also investigated. Fifteen young adults and 15 older adults were included in this study. Subjects were asked to perform the walking task alone (single-task trial) and walking in combination with a cognitive task (dual-task trial). Four walking conditions (1 single task and 3 dual task trials)×two walking surfaces were encountered. Both age groups had greater elbow and trunk movement in the sagittal plane under the dual task trials as compared to the single task trial (p<.05). Subjects had greater upper extremity and upper body movement on the soft floor than on the hard floor (p<.05). Subjects had greater movement amplitude when confronting a challenging environment, especially in the contralateral side. Among gender, there was a group-gender interaction: the older females had smaller upper extremity movement than the older males (p<.05) but the opposite was true for the young adults. The results suggest that different age groups of males and females use different balance control strategy to deal with the challenging conditions.     

Motor Programming

In many activities, the human being must quickly decide on the response to be produced following a change in the environment. In some of these situations, the limb that the individual chooses to carry out a response seems to be a significant element in performance. Thus, if the individual carries out the response with the limb closest to the target, the performance can improve because it will take less time to achieve the goal. However, it seems that in these situations, the human being does not take this decrease in movement time into consideration and that the response is carried out with the dominant hand. Why is this so? It may be because the reaction is faster when there doesn’t have to be a choice as to which limb will carry out the response. The goal of this study was to check this possibility. In order to do so, the subjects performed a two choice reaction-time task. For this task, some subjects knew beforehand which hand they had to use to carry out the response while other subjects were unaware of this fact. The results of two experiments indicate that the choice of the limb which is to carry out the response requires no particular delay when the movement to be produced is externally guided.     

Imitation of Goal Engagement and Disengagement Processes in Romantic Relationships

Individual differences in goal engagement and goal disengagement processes have been demonstrated to be related to goal attainment, health, and emotional well-being. However, there is a dearth of studies on the developmental conditions of individual differences in these processes. Social learning processes contribute to the formation of individual dispositions even in adulthood. As one pathway of learning, we investigated observational learning of goal regulation processes in romantic relationships in two experimental studies. Study 1 (N = 67 couples, M = 32.65 years) replicated a previous finding that observing partners imitated their partner's goal regulation processes in the same task and extended it by showing transfer effects to another task. Study 2 (N = 60 couples, M = 25.9 years) demonstrated that—given a lack of praise of the modelled actions—partners still imitated goal regulation processes but to a smaller extent. These findings lend support for observational learning as a pathway to individual differences in the application of goal regulation processes. © 2020 The Authors. European Journal of Personality published by John Wiley & Sons Ltd on behalf of European Association of Personality Psychology     

Evaluating movement performance: What you see isn’t necessarily what you get

With the goal of reducing injury and enhancing performance, movement screening tools score an individual’s movements against a standard and because it is a predictor of injury symmetry is often included in the score. Movement quality screening tools only consider kinematic asymmetry, which may underestimate the degree of asymmetry present during movement. Consider joint forces: if these forces are atypical, additional stress is created and control is reduced, which can lead to injury if the asymmetry is not addressed. The purpose of this study is to investigate movement symmetry in the kinematic, kinetic and muscle activity components of movement during a parallel squat.Thirty-four healthy individuals completed five body-weight, parallel squats. A motion capture system, two portable force plates, and electromyography (EMG) sensors recorded the squat motion, ground reaction forces and muscle activity. The variables of interest were the joint angles, joint moments, and EMG waveforms. Cross-correlations and normalized root-mean-square values were calculated for the left and right ankles, knees, and hips for each variable. A repeated-measures analysis of variance (ANOVA) tested for differences in symmetry (cross-correlation and nRMS) between the kinematic, kinetic, and muscle activity components at the ankle, knee, and hip during the squat.At all joints the kinematic component had the highest degree of symmetry, and the kinetic and muscle activity components showed poorer symmetry, with the muscle activity component being the least symmetric. The differences in symmetry between movement components suggests that movement performance evaluations should not rely exclusively on kinematics and observation to identify potential movement faults.     

Making Music Together: Discussion of Gianni Nebbiosi’s “The Smell of Paper”

Finding life in our patients is a common goal for analysts. Historically this project had been defined as one of freeing unacceptable impulses from their imprisoning defenses with the analyst, via interpretation, then contrasting the patient’s internal fantasied reality with “actual” reality. Untangling fantasy from reality could free the impulses to provide energy for more realistic projects. This imagery stands in stark contrast to the fluidity of a contemporary relational conceptualization of human experience where our inner experience is now understood to be the lens through which we construct our vision of external reality, always a subjective perception. Clinical change—finding life—now depends more on the activation of a generative intersubjective process between patient and analyst, which contributes to the expansion of the patient’s subjective experience. Gianni Nebbiosi’s use of music and of mime to help him feel his way into his patient’s and ultimately into his own similarly defended experience demonstrates the creativity and idiosyncratic clinical approaches that emerge from a contemporary relational orientation. This orientation recognizes the analyst’s subjectivity as a fundamental tool of clinical change—a vehicle through which any theoretical approach will necessarily be shaped. Differing approaches to a clinical situation do not always simply reflect theoretical disagreements; they may also reflect the expression of the particular subjectivity of the analyst.