Fractal properties and short-term correlations in motor control in cycling: influence of a cognitive challenge

Fluctuations in cyclic tasks periods is a known characteristic of human motor control. Specifically, long-range fractal fluctuations have been evidenced in the temporal structure of these variations in human locomotion and thought to be the outcome of a multicomponent physiologic system in which control is distributed across intricate cortical, spinal and neuromuscular regulation loops.Combined with long-range correlation analyses, short-range autocorrelations have proven their use to describe control distribution across central and motor components.We used relevant tools to characterize long- and short-range correlations in revolution time series during cycling on an ergometer in 19 healthy young adults. We evaluated the impact of introducing a cognitive task (PASAT) to assess the role of central structures in control organization.Autocorrelation function and detrending fluctuation analysis (DFA) demonstrated the presence of fractal scaling. PSD in the short range revealed a singular behavior which cannot be explained by the usual models of even-based and emergent timing.The main outcomes are that (1) timing in cycling is a fractal process, (2) this long-range fractal behavior increases in persistence with dual-task condition, which has not been previously observed, (3) short-range behavior is highly persistent and unaffected by dual-task.Relying on the inertia of the oscillator may be a way to distribute more control to the periphery, thereby allocating less resources to central process and better managing additional cognitive demands. This original behavior in cycling may explain the high short-range persistence unaffected by dual-task, and the increase in long-range persistence with dual-task.     

On the Psychological Function of Nationalistic “Whitelash”

A noticeable feature of the political discourse accompanying the rise of nationalism in white‐majority countries is that white people fare worse than other ethnic groups in their societies. However, it is unclear based on the extant literature why group‐based relative deprivation (GRD) would correlate with majority‐group nationalism. Here, we propose that the psychological function of nationalism for majority‐group members lies in its ability to assuage the negative feelings arising from GRD. Accordingly, in a New Zealand national probability sample (N = 15,607), we found that GRD among whites was negatively associated with well‐being. However, we also found an opposing indirect association mediated by nationalism. GRD was associated with higher nationalism, which was in turn associated with higher well‐being. These findings suggest that endorsing beliefs about national superiority is one way a nation’s dominant ethnic group can cope with the negative psychological consequences of perceiving that their group is deprived.     

The effect of decision timing on the willingness to costly reward cooperation and punish noncooperation: Sanctioning the past,the present,or the future

Numerous studies have demonstrated that sanctions can promote cooperation. However, it is important to know not only that sanctions can work but also under what conditions people are actually willing to sanction cooperation positively (i.e., reward) or noncooperation negatively (i.e., punish). In this article, we demonstrate that people use sanctions less often and sanction more mildly when they decide about sanctioning before (instead of after) the occurrence of others' (non)cooperation (Experiments 1 and 2), regardless of whether they decide directly afterwards or after a time delay (Experiment 2). Moreover, we reveal that beforehand (as compared with afterwards) people have not yet formed clear sanctioning preferences (Experiment 3). These findings corroborate our reasoning that the decision environment beforehand induces nonconsequential reasoning and thereby hampers people's willingness to sanction. We discuss the theoretical, methodological, and practical implications of our work.     

Reinforcement value and fixed‐interval performance

The concept of reinforcement value summarizes the effect of different variables, such as reinforcement delay, reinforcement magnitude, and deprivation level, on behavior. In the present set of experiments, we evaluated the effect of reinforcement devaluation on performance under FI schedules. The literature on timing and reinforcement value suggests that devaluation generates longer expected times to reinforcement than the same intervals trained under control conditions. We devalued reinforcement with delay in Experiments 1A, 1B, and 2, and diminished deprivation in Experiments 3A and 3B. Devaluation reduced response rates, increased the number of one‐response intervals, and lengthened postreinforcement pauses, but had inconsistent effects on other timing measures such as quarter life and breakpoint. The results of delayed reinforcement and diminished deprivation manipulations are well summarized as reinforcement devaluation effects. These results suggest that devaluation may reduce stimulus control. In addition, we argue that the process by which delayed reinforcement affects behavior might also explain some effects observed in other devaluation procedures through the concept of reinforcement value.     

Comparison of the trunk-pelvis and lower extremities sagittal plane inter-segmental coordination and variability during walking in persons with and without chronic low back pain

Inter-segmental coordination can be influenced by chronic low back pain (CLBP). The sagittal plane lower extremities inter-segmental coordination pattern and variability, in conjunction with the pelvis and trunk, were assessed in subjects with and without non-specific CLBP during free-speed walking. Kinematic data were collected from 10 non-specific CLBP and 10 non-CLBP control volunteers while the subjects were walking at their preferred speed. Sagittal plane time-normalized segmental angles and velocities were used to calculate continuous relative phase for each data point. Mean absolute relative phase (MARP) and deviation phase (DP) were derived to quantify the trunk-pelvis and bilateral pelvis-thigh, thigh-shank and shank-foot coordination pattern and variability over the stance and swing phases of gait. Mann-Whitney U test was employed to compare the means of DP and MARP values between two groups (same side comparison). Statistical analysis revealed more in-phase/less variable trunk-pelvis coordination in the CLBP group (P < 0.05). CLBP group demonstrated less variable right or left pelvis-thigh coordination pattern (P < 0.05). Moreover, the left thigh-shank and left shank-foot MARP values in the CLBP group, were more in-phase than left MARP values in the non-CLBP control group during the swing phase (P < 0.05). In conclusion, the sagittal plane lower extremities, pelvis and trunk coordination pattern and variability could be generally affected by CLBP during walking. These changes can be possible compensatory strategies of the motor control system which can be considered in the CLBP subjects.     

学业不良的相对性涵义及测定的实证研究

本文在介绍和分析了国内外关于学业不良概念以及在心理学限定方面差异的基础上,就学业不良的相对性涵义进行了探讨,并对我国相对性学业不良者的测定进行了实证研究。其主要涉及到关于学业不良的相对性涵义、美国与我国对相对性学业不良者实际心理限定方面的差异;研究了“智力-成绩差距”的测定问题,包括客观判定标准值、自我主观认知因素的测定和教师的观察判定。     

Writing about patients III: Comparisons of attitudes and practices of analysts residing outside and within the USA

When analysts write about patients, they find themselves in a position of conflict. Their first loyalty is to their patients and maintaining confidentiality. However, they are also committed to advancing scientific knowledge in the psychoanalytic field. The attitudes and practices of 36 analysts residing outside the USA, who published articles using clinical material from their patients, are reported. Their attitudes and practices are compared with those of 30 author-analysts residing within the USA, who had been previously interviewed. Among the 66 analysts, geographic region was not a basis for distinguishing differences in attitudes or practices. Slightly more than twice as many analysts use only disguised material as regularly ask permission of their patients to write about them. The decision to use only disguise is somewhat more frequent for analysts who reside outside the USA than for those living within it. Analysts around the world are increasingly concerned about the accessibility of published material. More analysts have come to believe that it is necessary to ask permission before publishing material. Some analysts also believe that the request itself, and the patients reading written material about themselves, focus issues that are central to patients' characters and confl icts that can then be explored analytically.     

But Affirmative Action hurts Us! Race-related beliefs shape perceptions of White disadvantage and policy unfairness

Drawing on social identity theory, we examine how Whites’ race-related beliefs drive their reactions to race-based Affirmative Action Policies (AAPs). Across laboratory and field settings, we find that Whites with relatively high modern racism (MR) or collective relative deprivation (CRD) beliefs perceive greater White disadvantage in organizations that have race-based AAPs, than in organizations that do not. Alternatively, race-based AAPs do not lead to perceptions of White disadvantage among Whites with relatively low MR and CRD beliefs. We also find that White disadvantage mediates the relationship between the combined effects of race-based AAPs, MR beliefs, and CRD beliefs and the perceived fairness of the organization’s selection and promotion policies. Our findings suggest that race-based AAPs do not necessarily lead to perceptions of White disadvantage, but are contingent upon the interpretive lens of Whites’ MR and CRD beliefs, and also offer practical insights for preventing negative reactions to race-based AAPs.     

Distressed Mothers and Their Infants Use a Less Efficient Timing Mechanism in Creating Expectancies of Each Other’s Looking Patterns

The prediction of events and the creation of expectancies about their time course is a crucial aspect of an infant's mental life, but temporal mechanisms underlying these predictions are obscure. Scalar timing, in which the ratio of mean durations to their standard deviations is held constant, enables a person to use an estimate of the mean for its standard deviation. It is one efficient mechanism that may facilitate predictability and the creation of expectancies in mother-infant interaction. We illustrate this mechanism with the dyadic gaze rhythm of mother and infant looking at and looking away from each other's faces. Two groups of Hi- and Lo-Distress mothers were created using self-reported depression, anxiety, self-criticism and childhood experiences. Lo-Distress infants (controls) used scalar timing 100% of the time, about double that of Hi-Distress infants. Lo-Distress mothers used scalar timing about nine times as much as Hi-Distress mothers. The diminished use of scalar timing patterns in Hi-Distress mothers and infants may make the anticipation of each other's gaze patterns more difficult for both partners.