The influence of prior choices on current choice

Three pigeons chose between random-interval (RI) and tandem, continuous-reinforcement, fixed-interval (crf-FI) reinforcement schedules by pecking either of two keys. As long as a pigeon pecked on the RI key, both keys remained available. If a pigeon pecked on the crf-FI key, then the RI key became unavailable and the crf-FI timer began to time out. With this procedure, once the RI key was initially pecked, the prospective value of both alternatives remained constant regardless of time spent pecking on the RI key without reinforcement (RI waiting time). Despite this constancy, the rate at which pigeons switched from the RI to the crf-FI decreased sharply as RI waiting time increased. That is, prior choices influenced current choice-an exercise effect. It is argued that such influence (independent of reinforcement contingencies) may serve as a sunk-cost commitment device in self-control situations. In a second experiment, extinction was programmed if RI waiting time exceeded a certain value. Rate of switching to the crf-FI first decreased and then increased as the extinction point approached, showing sensitivity to both prior choices and reinforcement contingencies. In a third experiment, crf-FI availability was limited to a brief window during the RI waiting time. When constrained in this way, switching occurred at a high rate regardless of when, during the RI waiting time, the crf-FI became available.     

Goal setting in acquisition of a volleyball skill late in motor learning

To examine the effects of different types of goal setting on motor skill acquisition during advanced stages of learning. 44 female volleyball players were tested in four experimental training groups with generic goals, specific long-term goals, specific short-term goals, and as a control group. This study's pretest, training, and retention test phases used performance of a volleyball dig/forearm pass oriented to a target. Analyses yielded no significant differences among groups, although performance increased from pre- to retention test.     

Accounting for sequential trial effects in the flanker task: Conflict adaptation or associative priming?

The conflict-control loop theory proposes that the detection of conflict in information processing triggers an increase in cognitive control, resulting in improved performance on the subsequent trial. This theory seems consistent with the robust finding that conflict susceptibility is reduced following correct trials associated with high conflict: the conflict adaptation effect. However, despite providing favorable conditions for eliciting and detecting conflict-triggered performance adjustments, none of the five experiments reported here provide unequivocal evidence of such adjustments. Instead, the results corroborate and extend earlier findings by demonstrating that the conflict adaptation effect, at least in the flanker task, is only present for a specific subset of trial sequences that is characterized by a response repetition. This pattern of results provides strong evidence that the conflict adaptation effect reflects associative stimulus-response priming instead of conflict-driven adaptations in cognitive control.     

Human bilateral deficit during a dynamic multi-joint leg press movement

Bilateral deficit has been used to describe the phenomenon of a reduction in performance during synchronous bilateral movements when compared to the sum of identical unilateral movements. The study of bilateral deficit in humans under isometric, and to a lesser extent, dynamic conditions has shown bilateral decreases in force and muscle activation, and delayed reaction time. Results are equivocal, however, and biomechanical analyses of dynamic conditions, i.e., movements, are lacking. Our purpose was to determine, through an analysis of kinematic, kinetic, and electromyographic (EMG) data, whether or not bilateral deficit was present during a dynamic multi-joint movement under conditions where the external load was relatively equal for unilateral and bilateral efforts. Five male participants performed repeated unilateral and bilateral maximal horizontal leg press jumps under 100% (1BW) and 200% (2BW) relative body weight loads. Significant bilateral deficits in resultant ground reaction impulse of 27.7% and 13.0% were present in 1BW and 2BW, respectively. Maximum joint power at the hip exhibited significant deficits in both 1BW and 2BW of 35.6% and 25.1%, respectively. In both 1BW and 2BW conditions, ankle (15.5% and 11.5%), knee (10.9% and 5.7%), and hip (38.5% and 30.4%) work was significantly affected. Statistically significant EMG bilateral deficits were found in every muscle in both conditions except for rectus femoris during the 2BW trials. Bilateral deficit values ranged from 9.1% to 20.9% for 1BW, while deficits between 6.1% and 20.7% were found in 2BW. These results indicate that during dynamic leg press, bilateral deficit does exist, but that individual muscle activation levels and joint kinetics are not equally affected.     

Multiple environmental contexts and communication in pygmy marmosets (Cebuella pygmaea)

There are multiple components to the concept of Umwelt experienced by an organism that may constrain the type and structure of communication signals as well as the usefulness of these signals. To illustrate the impact of these multiple environmental components, the authors used signals of the pygmy marmoset (Cebuella pygmaea), a small primate from the western Amazon. The authors summarize studies to show how the physical effects of the habitat; effects of other species, both predators and nonpredators; anthropogenic effects on the communication environment; within-group and between-groups influences other pygmy marmosets exert; and ontogeny influence the structure and usage of vocal signals. Communication within a species can be understood only in consideration of each of these contexts.     

Implicit and explicit alcohol-related cognitions in heavy and light drinkers

Implicit and explicit alcohol-related cognitions were measured in 2 dimensions: positive-negative (valence) and arousal-sedation, with 2 versions of the Implicit Association Test (IAT; A. G. Greenwald, D. E. McGhee, & J. L. Schwartz) and related explicit measures. Heavy drinkers (n = 24) strongly associated alcohol with arousal on the arousal IAT (especially men) and scored higher on explicit arousal expectancies than light drinkers (n = 24). On the valence IAT, both light and heavy drinkers showed strong negative implicit associations with alcohol that contrasted with their positive explicit judgments (heavy drinkers were more positive). Implicit and explicit cognitions uniquely contributed to the prediction of 1-month prospective drinking. Heavy drinkers' implicit arousal associations could reflect the sensitized psychomotor-activating response to drug cues, a motivational mechanism hypothesized to underlie the etiology of addictive behaviors.     

高一学生学校适应与教师领导行为关系之初探

采用整群抽样的方法,选取538名学生被试,然后运用“学生在校行为问卷”和“教师领导行为问卷”考察学生的学校适应状况同他们感知到教师领导行为的关系,并分析了不同领导模式下学生学校适应状况的差异及性别因素的影响。结果发现学生的学校适应与其感知到的教师民主行为是正相关,而与权威和放任行为是负相关;民主型的领导模式明显好于权威和放任型的领导模式,而权威和放任之间的差距不明显,该结果不受学生和教师性别因素的影响。     

Commitment Shift during Organizational Upheaval: Physicians' Transitions from Private Practitioner to Employee

This longitudinal study examines the individual transition journeys of physicians as their private medical practices are acquired by a large integrated health care system. We test the proposition that transition patterns (trends in an individual's commitments to organization and profession over time) are a function of individual differences in years in profession and perceived organizational enabling characteristics (change involvement, openness to ideas, and work discretion). Three years of survey data were obtained from a panel of 48 physicians who transitioned through an organizational change process. Results challenge traditional assumptions that tenure reinforces commitment and cast doubt on the effectiveness of current medical school curricula in preparing medical graduates to practice in an administrative environment. In addition, results strongly suggest that enabling characteristics of organizational change are critical for compatibility between the organizational and professional attachments of transitioning physicians.