奖惩中枢与学习

奖惩现象及实验揭示了:兴奋了奖赏中枢的思想、行为(神经通路)能被奖赏中枢强烈易化,而兴奋了惩罚中枢的思想、行为能被惩罚中枢强烈抑制。在此基础上,通过讨论奖惩中枢在学习中的作用得出:思想、行为的动力由奖惩中枢影响产生;奖惩中枢在思想、行为(神经兴奋)习惯的选择、形成过程中起着主要作用。     

INFLUENCE OF ASSESSMENT CENTER METHODS ON ASSESSORS'RATINGS

Recently a number of authors have argued persuasively that performance ratings are influenced to a large extent by the way the rater selects, organizes, stores, and recalls information. Although the influence of the rater's cognitive processes on the obtained ratings has been considered in the job-performance evaluation literature, this issue has not been considered in the assessment center literature. The purpose of the present study was to examine how assessment center methods affect the way assessors organize and process assessment center information and affect the ratings they make. Independent groups of assessors underwent one of two methods for evaluating candidates in an assessment center. Data indicated differences in the convergent and discriminant validities and differences in the factor structures of the ratings for the two methods. The pattern of results suggested that the two methods for evaluating assessment center candidates affected the way the assessors organized the assessment center information and affected the obtained ratings. Future research should consider assessment center methods and assessors as sources of variation in assessment center ratings.     

Visual localization of the center of mass of compact, asymmetric, two-dimensional shapes.

This study aimed at understanding how visual information is used to locate the center of mass. The center of mass is an important physical property of objects that must be taken into account when grasping and/or manipulating them. Participants were instructed to identify the point of equilibrium of compact, bidimensional, massless shapes displayed on a touch screen. The point of equilibrium was defined as the point on the face of the object that would allow one to balance the object in the horizontal position. Seven different triangles and 18 different quadrilaterals in different orientations were used as stimuli. It was found that participants can accurately and consistently estimate the position of the center of mass. The small observed errors were systematically influenced by the shape of the object. The participants tended to locate the center of mass at the center of an inscribed circle instead of the true center of mass. In general, the shape effect was impervious to the orientation of the figure and to the mode of response (left hand, right hand, or mouse).     

Perception of two-body center of mass

Participants estimated the perceptual center of mass between two horizontally oriented black dots varying in size and distance. Experiment 1 showed that estimates, measured as distance from the larger dot's center, decreased with an increase in size ratio between the dots and a decrease in the distance between them, as predicted by the physical center-of-mass equation. The results were replicated and extended in further experiments with different ratios and distances. In all experiments, the true center was consistently overestimated, either because the stimuli were perceived in a low dimensionality or because of a hesitancy to place estimates near the larger dot's edge. In Experiment 4, the center was deliberately placed near this edge for one- and two-dimensional solutions. Participants still overestimated, indicating an "edge effect" as responsible.     

浅析专家会诊中心在门诊医疗中的作用

随着物质生活水平的日益提高,人们对医疗、保健的需求越来越高。为缓解看专家门诊难和在门诊能及时解决疑难杂症会诊问题,江苏省人民医院于1997年成立了高级专家会诊中心。中心成立十余年来,会诊、就诊的患者逐年增多,中心以优质的服务,得到患者的好评,作为门诊医疗的“特殊”窗口发挥了越来越大的作用。     

Diminished plantar cutaneous sensation and postural control

The purpose of this study was to assess the effect of diminished plantar cutaneous sensation induced by cooling on postural control during double- and single-limb quiet standing. 32 healthy adults were tested on an intervention day and control day. The intervention consisted of 10 min. of ice immersion of the plantar aspect of the feet prior to balance testing. Dependent variables were center of pressure velocity and area during double- and single-limb stance with eyes open and closed. Significant interactions were found between sensation and vision for double-limb center of pressure area, with a significant reduction in area of center of pressure excursions after reducing sensation with eyes closed but not with eyes open. The area of center of pressure excursions may have been reduced in an effort to curtail exploratory postural behavior given the altered afferent input from plantar receptors. There were no significant differences for plantar hypoesthesia in single-limb stance.     

Searching for the center: spatial cognition in the domestic chick (Gallus gallus)

Chicks learned to find food hidden under sawdust by ground-scratching in the central position of the floor of a closed arena. When tested inan arena of identical shape but a larger area, chicks searched at 2 different locations, one corresponding to the correct distance (i.e., center) in the smaller (training) arena and the other to the actual center of the test arena. When tested in an arena of the same shape but a smaller area, chicks searched in the center of it. These results suggest that chicks are able to encode information on the absolute and relative distance of the food from the walls of the arena. After training in the presence of a landmark located at the center of the arena, animals searched at the center even after the removal of the landmark. Marked changes in the height of the walls of the arena produced some displacement in searching behavior, suggesting that chicks used the angular size of the walls to estimate distances.     

The space of an object: object attention alters the spatial gradient in the surround

Although object-based attention enhances perceptual processing of information appearing within the boundaries of a selected object, little is known about the consequences for information in the object's surround. The authors show that distance from an attended object's center of mass determines reaction time (RT) to targets in the surround. Of 2 targets in the surround, both equidistant from a cue, the target closer to the center of mass was detected faster. Moreover, RT was shown to be a linear function of distance from the center of mass of a fixed, attended object, and changes to the shape of the object and its center of mass predictably altered RT. Object-based attention leads to a pattern of facilitation in the surround that may contribute to the organization of visual scenes.     

Stressful demands or helpful guidance? The role of display rules in Indian call centers

This paper utilizes conservation of resources (COR) theory and two of Hofstede's (1980) dimensions of culture (individualism and power distance) to examine the impact of display rules on job satisfaction and performance in an Indian call center sample. Contrary to findings in an American sample (Wilk & Moynihan, 2005), we proposed that due to cultural differences as well as differences in the nature of the job among representatives in an Indian call center, supervisory focus on display rules would reduce emotional exhaustion, and in turn, have positive consequences for employee performance and job satisfaction. Using multi-source data in a sample of 137 Indian call center representatives, results confirmed the hypothesized mediating effects of emotional exhaustion on performance and job satisfaction. Implications of these results for future cross-cultural research are presented.     

Stressful demands or helpful guidance? The role of display rules in Indian call centers

This paper utilizes conservation of resources (COR) theory and two of Hofstede's (1980) dimensions of culture (individualism and power distance) to examine the impact of display rules on job satisfaction and performance in an Indian call center sample. Contrary to findings in an American sample (Wilk & Moynihan, 2005), we proposed that due to cultural differences as well as differences in the nature of the job among representatives in an Indian call center, supervisory focus on display rules would reduce emotional exhaustion, and in turn, have positive consequences for employee performance and job satisfaction. Using multi-source data in a sample of 137 Indian call center representatives, results confirmed the hypothesized mediating effects of emotional exhaustion on performance and job satisfaction. Implications of these results for future cross-cultural research are presented.     

Dimensionality and the dynamics of human unstable equilibrium

Maintaining an unstable equilibrium requires that multiple joints be coordinated so that the center of mass is kept above the base of support. The authors' aim in the present study was to discover the underlying dynamics of local (foot, hip, or head) and global (center of mass) components involved in balance control and how those dynamics are affected by changes in the available information. Participants (N = 6) had to maintain their balance on an unstable platform. Using dimensional analyses (largest Lyapunov exponent and correlation dimension), the authors examined the active degrees of freedom involved in balance control. Results indicated a similarity in dimension between local (joints) and global (center of mass) components, between a fixed point and a limit cycle. The behavior of the center of mass was found to be more predictable than the behavior of its local constituents. In addition, the available visual information affected the predictability of the postural behavior, which suggests that vision is used in the stabilization of the low-dimensional dynamics underlying balance control.     

Evaluation of a Suicide Prevention Center by Sampling the Population at Risk*

ABSTRACT: At present there are no clear guidelines for assessing the effectiveness of suicide prevention and crisis centers. This report focuses on one readily available source of data, specifically that segment of the population at risk made up of persons admitted to the inpatient service of a mental health center due to depressive and/or suicidal states, including suicide attempts. To determine the role of the suicide prevention center in providing services to this group, 575 persons meeting these criteria were interviewed. The findings included the following: (a) 11 percent had utilized suicide prevention center services, with 59 percent of these experiencing substantial benefit; (b) 20 percent stated they were unaware of the center; (c) 8 percent expressed the view that calling the center would be inappropriate because a suicide attempt was not imminent; and (d) 26 percent indicated an inclination to call the center in the event of subsequent difficulties. Experience suggests that response to a crisis (intervention) as well as response to low lethality callers with “everyday problems” (prevention) constitute valid functions of a suicide prevention and crisis center. Preoccupation with short-term goals, such as reducing the apparent suicide rate, should not dominate the conceptualizing of program evaluation methods.     

Perceptual interference and hemispheric specialization

Two experiments evaluated the effect of stimuli presented at fixation on the recognition of faces or random shapes presented to the left or right visual half-field (VF). Increasing the processing demands of the center stimulus produced a large, linear decrease in recognition from both VFs for both faces and shapes. Recognition of random shapes was decreased more in the right visual field by center digits and in the left VF by center faces and shapes. In addition, interference was found between the VF faces and the center digits to the left of fixation. It was concluded that differences in the processing capacity of the two hemispheres are a function of the verbal-nonverbal nature of the stimuli at a later stage in processing but that the two hemispheres may also differ along other perceptual dimensions at an earlier stage of visual recognition.     

Feedback Seeking Among Developmental Assessment Center Participants

This study examined 189 newly hired supervisors in the transportation industry who completed a developmental assessment center. The results showed that those who performed poorly in the assessment center, particularly on interpersonal dimensions, were less likely to initiate a scheduled feedback telephone call with an assigned coach. Implications and future research ideas are discussed.     

Retinal location and string position as important variables in visual information processing

Three experiments were conducted to isolate the effects of retinal locus and string position in tachistoscopic letter recognition. Retinal locus proved to be an important variable even when its range was restricted to less than a degree from the center of the fovea. Performance was maximal at the center of the fovea, dropping off rapidly to about 1.5 deg from the center. From that distance on, the decline in performance was quite gradual. String position was also an important factor. Retinal locus and string position interacted in such a way that the end positions were less affected by retinal locus than the middle positions. It was also found that processing order, as distinct from report order, was a significant component of the string position effect.     

A new frame for frame-of-reference training: enhancing the construct validity of assessment centers

The authors undertook a comprehensive examination of the construct validity of an assessment center in this study by (a) gathering many different types of evidence to evaluate the strength of the inference between predictor measures and constructs (e.g., reliability, accuracy, convergent and discriminant relationships), (b) introducing a theoretically relevant intervention (frame-of-reference [FOR] training) aimed at improving construct validity, and (c) examining the effect of this intervention on criterion-related validity (something heretofore unexamined in the assessment center literature). Results from 58 assessees and 122 assessors suggested that FOR training was effective at improving the reliability, accuracy, convergent and discriminant validity, and criterion-related validity of assessment center ratings. Findings are discussed in terms of implications and future directions for both FOR training and assessment center practice.     

Lunar phases and crisis center telephone calls

The lunar hypothesis, that is, the notion that lunar phases can directly affect human behavior, was tested by time-series analysis of 4,575 crisis center telephone calls (all calls recorded for a 6-month interval). As expected, the lunar hypothesis was not supported. The 28-day lunar cycle accounted for less than 1% of the variance of the frequency of crisis center calls. Also, as hypothesized from an attribution theory framework, crisis center workers reported significantly greater belief in lunar effects than a non-crisis-center-worker comparison group.     

Pastoral consultation through a community Mental Health Center

Conclusion Pastoral consultation through a mental health center in Kansas has been a beneficial experience for participating clergymen and the mental health center staff. This consultation has provided interested clergymen an opportunity to learn effective ways of serving parishioners through the church. The clergymen and mental health center staff have also begun to realize the mental health implications of religious resources, as well as ways in which ministers and the mental health center staff can effectively work together in serving troubled individuals within the local community. Pastoral consultation may become a means through which other community mental health centers and local clergymen can form meaningful professional relationships. The continuance of a pastoral consultation program over a longer period of time is needed to determine its possibilities and liabilities for assistingA report of one aspect of a special study project on Community Clergy and Mental Health, made possible by a grant from W. Clement Stone to the Menninger Foundation.     

Rhesus macaques (Macaca mulatta) monitor uncertainty during numerosity judgments

Two rhesus macaques (Macaca mulatta) judged arrays of dots on a computer screen as having more or fewer dots than a center value that was never presented in trials. After learning a center value, monkeys were given an uncertainty response that let them decline to make the numerosity judgment on that trial. Across center values (3-7), errors occurred most often for sets adjacent in numerosity to the center value. The monkeys also used the uncertainty response most frequently on these difficult trials. A 2nd experiment showed that monkeys' responses reflected numerical magnitude and not the surface-area illumination of the displays. This research shows that monkeys' uncertainty-monitoring capacity extends to the domain of numerical cognition. It also shows monkeys' use of the purest uncertainty response possible, uncontaminated by any secondary motivator.