Choice, contingency discrimination, and foraging theory

Four pigeons were trained on eight or nine pairs of independent concurrent variable-interval schedules. The range of reinforcement ratios included extreme ratios (up to 532 to 1). Large samples of stable performance were gathered. Contrary to the findings of Davison and Jones (1995), the generalized matching law described choice more accurately than a contingency-discriminability model. Taking small samples (5 to 10 sessions) and applying a more liberal stability criterion used by Davison and Jones only increased the unsystematic variance in the data and in estimates of generalized-matching-law sensitivity. Because changing to dependent scheduling and inserting a changeover delay had no systematic effect, the deviations from generalized matching reported by Davison and Jones probably arose from imperfectly discriminated stimuli. Analysis of visits revealed that visits to the nonpreferred alternative were brief and approximately constant. When choice between the preferred (rich) and nonpreferred (lean) alternatives, regardless of position, was analyzed according to the generalized matching law, sensitivities approximated 1.0, with bias in favor of the lean alternative. This bias, which arose from an excessive frequency of visits to the lean alternative, explains undermatching as the result of fitting one line to a choice relation that consists of two displaced lines, both with a slope of 1.0. The pattern of deviation from the generalized matching line confirmed this account. The findings suggest an alternative analysis of choice that focuses on probability of visiting the lean alternative as the dependent variable. This probability was directly proportional to ratio of reinforcement. Matching, undermatching, and overmatching may all be explained by a view of concurrent performance based on foraging theory, in which responding occurs primarily at the rich alternative and is occasionally interrupted by brief visits to the lean alternative.     

时点,时距和时序信息加工之间相关性研究

本研究分为两个实验,分别采用预期式和回溯式范型,探讨时距、时序和时点三者之间信息加工的相关性,结果发现：同一时间经历,时距估计与时序判断随注意参与程度的增加,由负相关趋势向正相关变化;时距估计与时点离散度可能呈正相关趋势;时序判断与时点离散度随注意参与程度的增加,由负相关趋势向正相关变化。     

学前儿童对短时时距的区分及其认知策略

本研究以令儿童比较时距长短为手段进一步探查学前（５、６岁）儿童对短时时距的认知过程,挖掘幼儿的认知潜力。研究结果表明：１）学前５、６岁儿童已能区分只有几秒钟差异的短时时距;２）６岁儿童已能使用时间标尺测量时间,５岁儿童已有潜力把时间看成是可以计数的维量;３）两时距的时间差别大小是影响儿童认知成绩的主要因素之一。     

Involvement of cardiac,respiratory and gastrointestinal functions in neural responses to stressful events

In the stress concept, fight and flight situations as well as other CNS-controlled reaction patterns for alertness to danger have to be followed by or integrated with a restorative “build-up” process in order to maintain homeostasis. The “build-up” process can be studied physiologically for example after regular exercise or training. Under these conditions there is a decrease in resting sympathetic adrenergic activity and an increase in the parasympathetic vagal activity. A theoretical model for the “build-up” process in psychosomatic gastroenterology has previously been presented. The present paper deals with the “build-up” process in cardiovascular and respiratory tract diseases seen in athletes. Anorexia nervosa related to excess physical training is also discussed as well as the “build-up” process in severe obesity and psychosomatic gastroenterological disorders.     

Conditioned reinforcement as a function of duration of stimulus

Pigeons were provided with three keys. Pecking the center key produced grain on a schedule that alternated at unpredictable times between a variable-interval component and extinction. On concurrent variable-interval schedules, pecking either side key produced a stimulus associated with the variable-interval component on the center key provided that said schedule was currently in effect. The independent variable was the length of time this stimulus remained on the keys. Pecking one side key produced the stimulus for 27 seconds, whereas the duration produced by pecking the other key varied for successive blocks of sessions. For the first four birds, the values tested were 3, 9, 27, and 81 seconds. For the second group, numbering three birds, the values tested were 1, 3, 9, and 27 seconds. The dependent variable was the proportion of total side key pecks that occurred on the variable key. For all birds, the function was positive in slope and negative in acceleration. This finding supports a formulation that ascribes the maintenance of observing responses in a normal setting to the fact that the subject exposes itself to the positive discriminative stimulus for a longer mean duration than it does to the negative stimulus.     

Protective effect of aerobic fitness on the detrimental influence of exhaustive exercise on information processing capacity

Although aerobic fitness has been thought to protect against the detrimental cognitive effects following exhaustive exercise, available evidence from studies using traditional mean behavioral measures remain somewhat equivocal.PurposeThis study aimed to reconcile this discrepancy by using a novel theory-driven diagnostic tool, the Systems Factorial Technology (SFT).MethodsSixty-six healthy young adults aged from 18 to 30 years old with different levels of aerobic fitness (n = 33 for the higher-fit and lower-fit groups) completed a go/nogo version of redundant-target task before and after a graded exercise test (GXT) until exhaustion. SFT was used to calculate the resilience capacity, which reflects the information processing capacity underlying inhibitory control.ResultsFollowing the GXT, both higher-fit and lower-fit groups showed faster responses while leaving accuracy unchanged as compared to the performance at the pretest. On the other hand, the resilience capacity decreased for the lower-fit group but was maintained for the higher-fit group.ConclusionThe present findings suggest that aerobic fitness may modulate the individual difference in decisional mechanism following exhaustive exercise. In sum, this study offers an alternative mechanistic explanation regarding cognitive individual differences in response to exhaustive exercise and provides novel insights into the significance of maintaining a state of high physical fitness for those who need to perform cognitively challenging tasks under physically stressful conditions (e.g., elite athletes).     

The Effects of Tai Chi Chuan Relaxation and Exercise on Stress Responses and Well-Being: An Overview of Research

The rationale of this article is to review, analyze, and discuss studies concerning the role of Tai Chi in stress management and well-being, linking those studies to research on exercise, yoga, and relaxation with regard to physiological and psychological wellness. All studies reported in PsychLit and Medline between 1996 and 1999 directly related to the subject, plus other studies relevant for the analysis, are addressed in this review. Studies reviewed in this article characterize Tai Chi as a form of moderate exercise. Although Tai Chi may not be suitable for achieving aerobic fitness, it may enhance flexibility and overall psychological well-being. Cognitively, there are indications that Tai Chi exercise may lead to improvements in mood. However, it is not clear whether the positive effects of Tai Chi are due solely to its relaxation and meditation component, or whether they are the consequence of various peripheral factors, since it is known that stress reduction often occurs when we indulge in activities we find pleasurable and satisfying. An important finding is that all studies on the benefits of Tai Chi for senior adults have revealed positive results.     

体育锻炼对大学生主观幸福感的影响:人际关系困扰和自尊的中介作用

为考察影响体育锻炼与主观幸福感关系的内在机制,该研究采用体育锻炼量表、自尊量表、人际关系综合诊断量表以及Campbell主观幸福感指数量表对521名高校大学生进行调查.结果显示:(1)人际关系困扰与体育锻炼、自尊及主观幸福感呈显著负相关,体育锻炼、自尊、主观幸福感两两之间均呈显著正相关;(2)人际关系困扰和自尊在体育锻...     

Partner–objectification in romantic relationships: A dyadic approach

The present study investigated the relationship between the objectification of one's romantic partner (partner–objectification) and relationship quality using 221 heterosexual couples. Controlling for relevant covariates, actor–partner interdependence models revealed no partner effects but multiple actor effects. First, men who objectified their partners more had lower levels of relationship commitment and relationship satisfaction, and perceived higher quality alternatives to the relationship. Second, women who objectified their partners more had lower levels of relationship satisfaction themselves. Third, relationship duration marginally moderated the association between partner–objectification and relationship commitment, with partner–objectification negatively linked to one's own relationship commitment in relationships of shorter durations, but not when relationship durations were longer. Implications for an investment model and romantic relationship objectification are discussed.     

Hysteresis behaviour of psychobiological variables during exercise

ObjectivesThe rating of perceived exertion (RPE) and the heart rate (HR) have been widely studied and monitored during exercise, but their hysteresis behaviour is still unexplored. Our aim was to study the hysteresis behaviour of RPE and HR in triathletes and non-athletes.DesignCross-sectional study.MethodEighteen triathletes at different competitive levels (elite n = 9, non-elite n = 9) and ten students were tested while cycling and running, using a pyramidal protocol (incremental/decremental workloads). The hysteresis area, considered positive when values of the dependent variables (RPE and HR) at the same workload were higher in the decremental phase than in the incremental phase, and vice versa for the negative areas, was calculated in all tests. The Wilcoxon matched-pairs test and Kruskal Wallis ANOVA were applied to detect intra- and inter-group differences, respectively, of RPE and HR values during the incremental and decremental phases, as well as between cycling and running.ResultsThe following results were observed: a) an incoherent relationship of RPE with HR and workload, b) positive hysteresis areas of RPE and HR in all groups during cycling and running, c) a partial negative hysteresis area of RPE, but not of HR, in the triathlete groups, d) larger hysteresis areas of RPE and HR in students than in triathletes, and e) larger hysteresis areas in cycling than in running.Conclusionsthe study of the hysteresis behaviour of RPE and HR reveals the history dependency of both variables, highlights their incoherent or non-unique relationship during a pyramidal exercise, and questions their widely assumed linear association to workload intensity. The hysteresis area is proposed as a new non-invasive marker of exercise stress and tolerance that should be further investigated.