Quantification of upper limb kinetic asymmetries in front crawl swimming

This study aimed at quantifying upper limb kinetic asymmetries in maximal front crawl swimming and to examine if these asymmetries would affect the contribution of force exertion to swimming performance. Eighteen high level male swimmers with unilateral breathing patterns and sprint or middle distance specialists, volunteered as participants. A load-cell was used to quantify the forces exerted in water by completing a 30 s maximal front crawl tethered swimming test and a maximal 50 m free swimming was considered as a performance criterion. Individual force–time curves were obtained to calculate the mean and maximum forces per cycle, for each upper limb. Following, symmetry index was estimated and breathing laterality identified by questionnaire. Lastly, the pattern of asymmetries along the test was estimated for each upper limb using linear regression of peak forces per cycle. Asymmetrical force exertion was observed in the majority of the swimmers (66.7%), with a total correspondence of breathing laterality opposite to the side of the force asymmetry. Forces exerted by the dominant upper limb presented a higher decrease than from the non-dominant. Very strong associations were found between exerted forces and swimming performance, when controlling the isolated effect of symmetry index. Results point that force asymmetries occur in the majority of the swimmers, and that these asymmetries are most evident in the first cycles of a maximum bout. Symmetry index stood up as an influencing factor on the contribution of tethered forces over swimming performance. Thus, to some extent, a certain degree of asymmetry is not critical for short swimming performance.     

Social dilemmas between individuals and groups

Three computer-controlled experiments were conducted to study interactions between individuals and non-cooperative groups in prototypical social-dilemma games. The asymmetric competition between an individual and a group was compared with symmetric control conditions where both competitors were either individuals or groups. All games were played repeatedly with the same players interacting for 120 rounds. The results show that the outcome of the conflict depends both on the type of competing players and on the structure of the competition. Generally, individuals do better than non-cooperative groups, regardless of the type of conflict, and more often than not it is better to have a non-cooperative group rather than an individual as an opponent. The relative advantage is a result of individuals generally cooperating better with other individuals (as compared to cooperation between two groups), and that in mixed competitions the individual takes advantage of the group’s difficulties in mobilizing collective-action, and dominates it.     

Social perceptions of male and female extreme mesomorphs.

In this study, male and female university students in the United States were exposed to mesomorphic or nonmesomorphic stimuli as reflected by photographs of either male body builders and non-body builders or female body builders and non-body builders. Then they were asked to attribute various personality traits and sex-role behaviors to them. Subjects, irrespective of their sex, perceived male and female body builders as possessing more traditionally masculine and less traditionally feminine personality characteristics than male and female non-body builders. Also, male and female body builders were seen as possessing less socially desirable traits than non-body builders. As predicted, female body builders were perceived generally as being more likely to engage in traditionally masculine sex-role behaviors in their dating and marriage relationships than female non-body builders. Contrary to expectation, however, male body builders were not perceived as more likely to engage in higher levels of masculine sex-role behaviors than male non-body builders.     

Social anxiety and post-event processing among African-American individuals

Background: Social anxiety is among the most prevalent psychiatric conditions, yet little attention has been paid to whether putative cognitive vulnerability factors related to social anxiety in predominantly White samples are related to social anxiety among historically underrepresented groups.

Design: We tested whether one such vulnerability factor, post-event processing (PEP; detailed review of social event that can increase state social anxiety) was related to social anxiety among African-American (AA; n?=?127) persons, who comprise one of the largest underrepresented racial groups in the U.S. Secondarily, we tested whether AA participants differed from non-Hispanic White participants (n?=?127) on PEP and social anxiety and whether race moderated the relation between PEP and social anxiety.

Method: Data were collected online among undergraduates.

Results: PEP was positively correlated with social anxiety among AA participants, even after controlling for depression and income, pr?=?.30, p?=?.001. AA and White participants did not differ on social anxiety or PEP, β?=??1.57, 95% CI: ?5.11, 1.96. The relation of PEP to social anxiety did not vary as a function of race, β?=?0.00, 95% CI: ?0.02, 0.02.

Conclusions: PEP may be an important cognitive vulnerability factor related to social anxiety among AA persons suffering from social anxiety.     

Social anxiety and perceptions of likeability by peers in children

The current study aimed to investigate the discrepancy between self-reported and peer-reported likeability among children, and the relation with social anxiety, depression, and social support. In total, 532 children between 7 and 12 years completed questionnaires about social anxiety symptoms, depressive symptoms, and social support, estimated their own likeability, and indicated how much they liked their classmates. Children with higher levels of social anxiety or depression overestimated their likeability less or even underestimated their likeability. Social anxiety symptoms, but not depressive symptoms, were significant predictors of the discrepancy. Social support was positively related to likeability and negatively related to social anxiety, but did not moderate the association between social anxiety symptoms and perception accuracy of likeability. These results are in line with cognitive theories of childhood social anxiety, and they stress the importance of using multi-informant measures when studying the relation between social anxiety and social functioning in children.     

自闭症谱系障碍个体的社会动机缺陷

自闭症谱系障碍(ASD)是一种源于儿童期的神经发育障碍, 社会交往障碍是其核心特征, 与社会动机缺陷密切相关。社会动机是引导个体社会行为的强大动力, 主要表现为社会定向、社会奖赏和社会维持。现有研究表明, ASD个体的社会动机发展存在缺陷, 他们对社会刺激的注意偏向减少, 不能主动寻求和体会社会互动带来的快乐, 且缺乏维持社会关系的行为策略等。然而, 相关研究结果受到个体特征、环境和实验设计等因素的影响。研究者未来应综合考虑这些影响因素, 加强对ASD个体社会动机理论的整合研究, 以便全面系统地了解ASD个体的社会动机缺陷。     

Social game theory: Preferences,perceptions, and choices

ABSTRACT

Building on classic game theory, psychologists have explored the effects of social preferences and expectations on strategic behaviour. Ordinary social perceivers are sensitive to additional contextual factors not addressed by game theory and its recent psychological extensions. We review the results of a research programme exploring how observers judge “players” (i.e., individuals making strategic decisions in social dilemmas) on the dimensions of competence and morality. We explore social perception in several well-known dilemmas, including the prisoner’s dilemma, the volunteer’s dilemma, and the trust dilemma. We also introduce a novel self-presentational dilemma. In research conducted over a decade and a half, we have found that judgements of competence are sensitive to both players’ choices and the dilemma’s (expected and actual) outcomes. In contrast, judgements of morality respond strongly to players’ behaviour and little else. We discuss how these social-perceptual patterns might affect expectations, preferences, and strategic choices.     

Contribution of upper trunk rotation to hand forward-backward movement and propulsion in front crawl strokes

The study aims to test three hypotheses: (a) the rotation of the upper trunk consists of roll, pitch and yaw of frequencies harmonic to the stroke frequency of the front crawl stroke, (b) the rotation of the upper trunk generates back-and-forth movements of the shoulders, which enhances the movements of the stroking arms, and (c) the angular velocities of roll, pitch and yaw are associated with hand propulsion (HP). Front crawl strokes performed by twenty male swimmers were measured with a motion capture system. The roll, pitch and yaw angles about the three orthogonal axes embedded in the upper trunk were determined as three sequential Cardan angles and their angular velocities were determined as the three respective components of the angular velocity. HP and the drag and lift components of HP (HP_D and HP_L) were estimated by the hand positions and the data from twelve pressure sensors attached on hands. The roll, pitch, and yaw angles were altered in frequencies harmonic to the stroke frequency during the front crawl stroke. Shoulders alternately moved back and forth due to the upper trunk rotation. In the pull phase the angular velocity of roll was correlated with HP_L (r = −0.62, p = 0.004). Based on the back-and-forth movements of the shoulders and roll motion relative to a hand movement, the arm-stroke technique of the front crawl swimming was discussed in terms of increasing the hand velocity and HP.     

Reliability of upper extremity kinematics while performing different tasks in individuals with stroke

Assessments of upper extremity performance typically include qualitative rather than quantitative measures of functional ability. Kinematic analysis is an objective, discriminative measure that quantifies movement biomechanics; however, the use within the poststroke impaired upper extremity is not well established. The purpose of this study was to examine the reliability of upper extremity kinematics in 18 individuals with stroke and 9 healthy controls. Participants performed reaching and grasping tasks over 2 separate days and metrics included movement time, peak velocity, index of curvature, trunk displacement, maximum aperture, and percentage of the movement cycle where maximum aperture occurred. The results showed moderate to high intraclass correlation and low standard error of measurement values for most variables, demonstrating that kinematic analysis may be a feasible and useful tool to quantify upper extremity movement after stroke.     

Social influence and sex effects on task performance and task perceptions

A laboratory experiment was conducted to investigate the effects of observer presence and subject sex on both performance quantity and quality, job satisfaction, and task perceptions. Multivariate analysis of covariance (MANCOVA) results demonstrated statistically significant multivariate effects on the performance measures. Significant main effects of observer presence were found for performance quality but not quantity. A significant observer presence x subject sex interaction was found for performance quantity. The results for task perceptions supported the hypothesis that the situational factors would make salient the significance of the task. Main effects of observer presence were found for task significance only. Also there was a significant observer presence x subject sex interaction on perceptions of task significance. No effects were found on job satisfaction, consistent with past research. The results are discussed relative to social facilitation research in the broader context of social influence.     

Modeling college women's perceptions of elite leadership positions with Social Cognitive Career Theory

The utility of Social Cognitive Career Theory (SCCT; Lent, Brown, & Hackett, 1994) for predicting college women's interests and goals for positions of elite leadership was examined with 156 undergraduate women at a public university. They completed measures of elite leadership self-efficacy expectations, outcome expectations, interests, and goals. Results supported SCCT as a theoretical framework for understanding internal factors that may contribute to women's elite leadership interests and goals. Self-efficacy and outcome expectations for elite leadership positions related positively to interests and goals for such positions, and self-efficacy and outcome expectations each contributed unique variance to the prediction of elite leadership interests. Outcome expectations partially mediated the relation between elite leadership self-efficacy and interests, interests partially mediated the relation between elite leadership outcome expectations and goals, and the combination of elite leadership interests and outcome expectations completely mediated the relation between self-efficacy for elite leadership positions and elite leadership goals.     

Social identity and perceptions of torture: It's moral when we do it

Two studies examined the effects of social identity concerns on the moral justification of torture. British and American nationals read a media report concerning the torture of a terrorist suspect that they were led to believe had been perpetrated either by members of their own nation's security services or by another nation's security services. When the torture was perpetrated by the ingroup, participants described it as more morally justified than when the torture was perpetrated by the other nation's security services. This effect was mediated by participants' decreased empathy for the ingroup's torture victim (Study 1), as well as increased victim blame and perceiving the perpetrators as prototypical of their national group (Study 2). We consider how social identity concerns enable moral justification of harm doing.     

Social stereotypes and judgments of individuals: An instance of the base-rate fallacy

Social stereotypes may be defined as beliefs that various traits or acts are characteristic of particular social groups. As such, stereotypic beliefs represent subjective estimates of the frequencies of attributes within social groups, and so should be expected to “behave like” base-rate information within the context of judgments of individuals: specifically, individuating target case information should induce subjects to disregard their own stereotypic beliefs. Although the results of previous research are consisten with this prediction, no studies have permitted normative evaluation of stereotypic judgments. Because the hypothesis equates base rates and stereotypes, normative evaluation is essential for demonstrating equivalence between the base-rate fallacy and neglect of stereotypes in the presence of individuating case information. Two experiments were conducted, allowing for normative evaluation of effects of stereotypes on judgments of individuals. The results confirmed the hypothesis and established the generalizability of the effect across controversial and uncontroversial, socially desirable and socially underirable stereotypic beliefs. More generally, an examination of the differences between intuitive and normative statistical models of the judgment task suggest that the base-rate fallacy is but one instance of a general characteristic of intuitive judgment processes: namely, the failure to appropriately adjust evaluations of any one cue in the light of concurrent evaluations of other cues.     

Social perspective taking and use of discounting in children's perceptions of others' helping behavior

The authors investigated the relationship between children's ability to take the social perspective of another and their use of the causal attribution principle known as discounting in assessing others' kindness in helping. The participants (N = 153), 7 to 16 years old, were interviewed in a township bordering Johannesburg. Each participant was administered 2 perspective-taking tasks and a series of vignettes, based on prosocial versus self-interested motives, assessing perceptions of kindness in helping. A significant relationship was established at p < .01 between social perspective-taking ability and use of discounting, such that participants at higher perspective-taking levels judged helpful behavior as significantly less kind than did their peers when the behavior was motivated by self-interest. This finding is interpreted in terms of literature suggesting that advances in perspective taking facilitate the recognition of the manipulative function of externally offered incentives. Observations are made regarding the cross-cultural investigation of these variables.     

社会支持缓解高互依自我个体的急性心理应激反应

高互依自我构念个体以社会角色来定义自己, 更看重自己的社会关系; 社会评价威胁是诱发个体社会心理应激反应的重要情境因素, 然而高互依自我构念个体在心理性应激情境中是否会表现出更高的应激反应, 以及社会支持是否会缓解高互依自我构念个体的急性心理应激反应还不可知。本研究以特里尔社会应激测试为范式, 以主观应激报告、心率和唾液皮质醇作为应激指标, 使用自我构念问卷测量个体互依自我构念水平, 将健康大学生被试随机分配到自我支持启动组和社会支持启动组。结果发现, 互依自我构念水平正向预测个体在应激情境中的皮质醇水平增加量; 同时, 相比于自我支持启动, 高互依自我构念的个体在经历社会支持后有更低的唾液皮质醇变化量。研究结果提示, 社会支持对高互依自我构念个体的急性心理应激反应起到了良好的缓解作用。