Planned Straight or Biased to Be So? The Influence of Visual Feedback on Reaching Movements

Abstract

Behavioral studies consistently find that subjects move their hand along straight paths despite considerations that suggest reaches should be curved. Literature on this topic makes it clear that the experimentally displayed feedback influences how subjects reach. Could the standard visual feedback, a displayed cursor, explain the lack of path curvature in experimental results? To address this question, we conducted three experiments to examine reach behavior in the absence of the standard visual feedback. In the first experiment, we found significant increases in curvature as visual feedback was progressively extinguished across groups. A second experiment revealed that practiced reaches became curved after the standard visual feedback was removed. A final experiment found that subjects’ reaches made before and after a brief display of visual feedback were similar, indicating a preference for specific curved trajectories. Our results suggest that the consistently straight reaches often observed could be due to a bias to move the displayed cursor straight, which when removed reveal subject-specific preferences for reaches that are often curved.     

Effect of Stroke on Joint Control during Reach-to-Grasp: A Preliminary Study

Abstract

We investigated changes in control of inter-segmental dynamics underlying upper extremity dyscoordination caused by stroke. Individuals with stroke and healthy individuals performed a natural reach-to-grasp movement. Kinetic analysis revealed that both groups rotated the shoulder by muscle torque and used interaction torque to rotate the elbow. However, individuals with stroke used interaction torque less than healthy individuals, actively suppressing a substantial portion of it. This resulted in inefficient use of active control and dyscoordination of the upper extremity. The degree of interaction torque suppression and inefficiency of active control at the elbow positively correlated with stroke severity. The increased interaction torque suppression can be a strategy used by individuals with stroke to compensate for deficient feedforward control of this torque.     

3～4岁幼儿冷热自我调节的发展趋势及性别差异——一项纵向研究

自我调节是个体发展和社会化的重要标志,在学前阶段发展迅速。研究选取白天-黑夜、头脚任务、延迟等待等实验范式,考察219名3岁幼儿一年内（3次测试）冷热自我调节的发展趋势及性别差异。结果表明：（1）二因素模型拟合显著好于单因素模型,冷热两成分中度相关;（2）幼儿的冷自我调节中度稳定,热自我调节中低度稳定;（3）幼儿的抑制控制与延迟等待随年龄增加而提高,女孩的延迟等待提高后保持稳定;（4）整体来看,幼儿的抑制控制和延迟等待存在显著性别差异,但具体来看,女孩的抑制控制仅在早期高于男孩,在延迟等待方面却始终高于男孩。结论：3~4岁女孩的冷热自我调节发展不同步,女孩的“性别优势”只在热自我调节上始终存在。     

粗暴养育与青少年学业成绩:有调节的中介分析

以往研究表明消极的养育行为损害青少年学业成绩,但对两者之间的关系机制缺乏探究。本研究通过检验一个有调节的中介模型,考察了父母消极归因情境下努力控制在粗暴养育和青少年学业成绩之间的中介作用。880名初中生作为被试,填写粗暴养育问卷、努力控制分量表、儿童责任归因分量表,并以语文、数学和英语的成绩均值作为学业成绩的指标。结果显示：（1）控制性别、年龄、社会经济地位后,粗暴养育与学业成绩呈显著负相关;（2）努力控制是粗暴养育与学业成绩之间的中介变量;（3）粗暴养育通过努力控制对学业成绩的间接效应受父母消极归因的调节。因此,矫正父母消极的养育行为和归因模式,改善孩子的自控能力,有利于改善其学业成绩。     

Patterns of agonistic interactions in three species of macaque (Macaca mulatta,M fascicularis,M tonkeana)

Patterns of aggression and response to aggression were studied in three groups of macaques living in semiliberty, each group representing a different species: Macaca mulatta, M fascicularis, and M tonkeana. In Macaca mulatta, intensity of aggression is high (biting is frequent) and symmetry in aggression is low: the aggressee most often flees or submits. In Macaca tonkeana, in contrast, biting is exceptional, aggression is very often bidirectional, and appeasement behaviors are frequently observed. Intermediate patterns are found in Macaca fascicularis with, in addition, especially frequent mild forms of submission. It is argued that relationships exist between intensity of aggression, symmetry in aggression, and development of behaviors controlling aggresssion. Whether balances between these variables are species-specific is discussed.     

Commentaries on “Beyond statistical significance: Five principles for the new era of data analysis and reporting”

Three commentaries below provide different perspectives on data analysis and reporting. They generally focus on how the quality of the measures and manipulations determines the value of the analysis. Norbert Schwarz and Fritz Strack's comment is less on the right statistic and more on “sloppy reasoning, gaps between theoretical concepts and their operationalizations, and blissful ignorance of the situated nature of human thinking, feeling, and doing contribute more to the limited reproducibility of empirical findings than the choice of a particular test statistic.” They propose that particular effects are contextual and inappropriately labeled as true or false. Instead, our job is to focus on general constructs that make sense of the diversity of human experience and psychological reactions. Too often studies replicating psychological effects in the noisy and confounded conditions of the marketplace result in statistical uncertainty of garbage in, garbage out. Researchers instead need to look toward tests of specific interactions, which can clarify the influencing factors based on theoretical considerations. The second comment is by Andrew Gelman, an outstanding psychological statistician. He proposes that “once the data have been collected, the most important decisions have already been done.” He then provides four recommendations that enable the statistics to work appropriately. The first requirement of an effective study is to be sure that the measures address the construct of interest. Similar to the position of Schwarz and Strack, it is important to articulate the relevance of a statistically significant finding. The second recommendation seeks to curb large number of studies with inflated effect sizes built from narrow studies and unwarranted optimism. The third recommendation is to simulate data from a model and consider the distribution of possible results. That is often done to test a new analysis method, but it can be even more important in marketplace studies where novel characteristics of the sample and experimental conditions are included in the analysis. Finally, he recommends that one consider likely analyses needed before getting the data. Such foresight would encourage, for example, thinking about the kind of data needed to defend the equality of the control demographics against the treatment. The final commentary is by Stijn van Osselaer. He agrees that p-values reflect the detailed methods from a given study but do not focus on the problem of generalizability. Like Gelman, he sees designs focused on effect sizes may have generated too many studies that do not replicate. He contrasts broad explorations with narrowly defined existence tests that provide evidence that an effect exists somewhere but are mute on other contexts where they may apply. For theoretical problems relevant to applications, it is important to identify moderators through broad sampling across population characteristics, stimuli, and situations. He proposes that consumer psychologists should not try to do everything in one paper, but to build practically relevant, applicable knowledge across multiple articles. Different articles, authors, and research methods play various roles, with each article focusing on important stages in the process from generating hypotheses, providing existence proofs, and exploring their broad applicability. That pragmatic approach can integrate theoretical silos that seek to resolve complex human problems and has promise as a criterion for relevant publications.     

Eating Disorder Examination Questionnaire (EDE-Q): norms for young adult women

In order to establish norms for the Eating Disorder Examination Questionnaire (EDE-Q) among young adult women, the questionnaire was administered to a large general population sample of women aged 18-42 yr in the Australian Capital Territory (ACT) region of Australia. Normative data were derived for EDE-Q subscales and for the occurrence of specific eating disorder behaviours, for each of five age bands (18-22, 23-27, 28-32, 33-37, 38-42 yr). Mean scores (SDs) for the Restraint, Eating Concern, Weight Concern and Shape Concern subscales for the total sample (n = 5,255) were, respectively, 1.30 (1.40), 0.76 (1.06), 1.79 (1.51) and 2.23 (1.65). The mean global score was 1.52 (1.25). The regular occurrence of objective and subjective overeating episodes was reported by 10.6% and 12.7% of participants, respectively. The regular use of self-induced vomiting, laxative misuse, and use of diuretics, was reported by 1.4%, 1.0%, and 0.3%, of participants, respectively, while 2.2% of participants reported regularly using diet pills. "Extreme dietary restraint" and "excessive exercise" were reported by 3.4% and 4.9% of participants, respectively. Both attitudinal and behavioural features of eating disorder psychopathology tended to decrease with increasing age. These data will inform researchers intending to use the EDE-Q in epidemiological studies.     

Avoidance behavior in panic disorder: the moderating influence of perceived control

The relations among anxiety sensitivity, perceived control, and agoraphobia were examined in 239 patients diagnosed with panic disorder (PD). Most patients exhibited agoraphobia accompanying their PD (98% situational avoidance; 90% experiential avoidance; and 80% endorsed interoceptive fear and avoidance). Anxiety sensitivity and perceived emotional control were associated with agoraphobia, and perceived threat control was found to moderate the relationship between anxiety sensitivity and agoraphobia. Lower levels of perceived control were associated with a stronger relationship between anxiety sensitivity and agoraphobia. Results were consistent for self-reported and clinician-rated agoraphobia. Implications for the role of perceived control in agoraphobia development and treatment are discussed.     

A preliminary analysis of self-control with aversive events: the effects of task magnitude and delay on the choices of children with autism

When faced with a choice between two aversive events, a person exhibits self-control by choosing a smaller, more immediate aversive event over a larger, delayed aversive event. Task demands are often aversive to children with autism and other developmental disabilities. The purpose of this study was to evaluate behavioral sensitivity to differences in the amount and delay of tasks as part of a preliminary study on self-control. Participants were 2 children with autism who engaged in problem behavior maintained by escape. Results indicated a lack of self-control with respect to choosing between two aversive tasks and suggested potential strategies for increasing self-control (i.e., choosing a small immediate task over a large delayed task).     

About Skinner and time: behavior-analytic contributions to research on animal timing

The article discusses two important influences of B. F. Skinner, and later workers in the behavior-analytic tradition, on the study of animal timing. The first influence is methodological, and is traced from the invention of schedules imposing temporal constraints or periodicities on animals in The Behavior of Organisms, through the rate differentiation procedures of Schedules of Reinforcement, to modern temporal psychophysics in animals. The second influence has been the development of accounts of animal timing that have tried to avoid reference to internal processes of a cognitive sort, in particular internal clock mechanisms. Skinner's early discussion of temporal control is first reviewed, and then three recent theories-Killeen & Fetterman's (1988) Behavioral Theory of Timing; Machado's (1997) Learning to Time; and Dragoi, Staddon, Palmer, & Buhusi's (2003) Adaptive Timer Model-are discussed and evaluated.