EFFECT OF REINFORCER MAGNITUDE ON PERFORMANCE MAINTAINED BY PROGRESSIVE‐RATIO SCHEDULES

This experiment examined the relationship between reinforcer magnitude and quantitative measures of performance on progressive‐ratio schedules. Fifteen rats were trained under a progressive‐ratio schedule in seven phases of the experiment in which the volume of a 0.6‐M sucrose solution reinforcer was varied within the range 6–300 μl. Overall response rates in successive ratios conformed to a bitonic equation derived from Killeen's (1994) Mathematical Principles of Reinforcement. The “specific activation” parameter, a, which is presumed to reflect the incentive value of the reinforcer, was a monotonically increasing function of reinforcer volume; the “response time” parameter, δ, which defines the minimum response time, increased as a function of reinforcer volume; the “currency” parameter, b, which is presumed to reflect the coupling of responses to the reinforcer, declined as a function of volume. Running response rate (response rate calculated after exclusion of the postreinforcement pause) decayed monotonically as a function of ratio size; the index of curvature of this function increased as a function of reinforcer volume. Postreinforcement pause increased as a function of ratio size. Estimates of a derived from overall response rates and postreinforcement pauses showed a modest positive correlation across conditions and between animals. Implications of the results for the quantification of reinforcer value and for the use of progressive‐ratio schedules in behavioral neuroscience are discussed.     

错误相关负波（ERN）在精神病理学研究中的应用

错误相关负波（error-related negativity, ERN）是由行为错误诱发的一种脑电波成分,最大峰值在错误反应之后的50ms左右,偶极子源定位于前扣带回（anterior cingulate cortex, ACC）附近。错误加工（error processing）的经典研究范式中出现的ERN成分可能反映了ACC具有错误检测、冲突监控、强化学习、情绪动机等功能。大量研究表明过度的和不足的错误相关脑活动（hyperactive and hypoactive error processing）可能分别与精神病理学的内化性和外化性障碍（internalizing and externalizing disorders）相关联。内化性和外化性障碍的内表型（endophenotype）的研究,还存在许多值得进一步探索的问题。     

Belief in a just world and subjective well-being: mothers of normal and Down syndrome children

A cross-sectional study examined the relationship between three dimensions of the belief in a just world and the subjective well-being of Pakistani mothers of normal and Down syndrome children (n = 100 each). Personal belief in a just world and two dimensions of general belief in a just world-beliefs in immanent and ultimate justice-were assessed along with four dimensions of subjective well-being: life satisfaction, mood, state anxiety, and depression. It was hypothesized that personal belief in a just world and belief in ultimate justice would be positively associated with subjective well-being for both groups of mothers. Results were obtained through moderated regression analyses. In line with our hypothesis, personal belief in a just world positively predicted life satisfaction and mood level and negatively predicted state anxiety and depression in both groups of mothers. In contrast, beliefs in immanent and ultimate justice were not consistently adaptive. In particular, the more the mothers of a Down syndrome child believed in immanent justice, the more anxiety they experienced the previous week. In addition, the more the mothers of normal children believed in ultimate justice, the more they experienced anxiety. The pattern of results persisted when controlled for mothers' education, the total number of their children and marital status. Overall, the results support the role of personal belief in a just world as a personal resource in adverse as well as normal life circumstances.     

Stimulus disparity and punisher control of human signal-detection performance

The present experiment examined the effects of varying stimulus disparity and relative punisher frequencies on signal detection by humans. Participants were placed into one of two groups. Group 3 participants were presented with 1:3 and 3:1 punisher frequency ratios, while Group 11 participants were presented with 1:11 and 11:1 punisher frequency ratios. For both groups, stimulus disparity was varied across three levels (low, medium, high) for each punisher ratio. In all conditions, correct responses were intermittently reinforced (1:1 reinforcer frequency ratio). Participants were mostly biased away from the more punished alternative, with more extreme response biases found for Group 11 participants compared to Group 3. For both groups, estimates of discriminability increased systematically across the three disparity levels and were unaffected by the punisher ratios. Likewise, estimates of response bias and sensitivity to the punisher ratios were unaffected by changes in discriminability, supporting the assumption of parameter invariance in the Davison and Tustin (1978) model of signal detection. Overall, the present experiment found no relation between stimulus control and punisher control, and provided further evidence for similar but opposite effects of punishers to reinforcers in signal-detection procedures.     

Alcohol‐related violence defined by ultimate goals: a qualitative analysis of the features of three different types of violence by intoxicated young male offenders

Based upon a functional approach to understanding aggression, we aimed to identify the occurrence of and to describe the features of three types of alcohol‐related violence defined a priori by ultimate goals: (1) violence in pursuit of nonsocial profit‐based goals, (2) violence in pursuit of social dominance goals, and (3) violence as defence in response to threat. A sample of 149 young men with offences of violence that were alcohol related was interviewed. Cases were classified and detailed information from the first ten cases in each class (N=30) was subjected to thematic analysis. Intoxicated violence in pursuit of nonsocial profit‐based goals was opportunistic and motivated by the desire for more alcohol or drugs. Violence, in these cases, although serious, appeared to be brief. Intoxicated violence in pursuit of social dominance goals was typically precipitated by past or current insult or injury, and was accompanied by strong anger and an adrenaline rush. Attacks were ferocious, and robbing the victim was not uncommon, perhaps to inflict additional humiliation. Feelings of pride and satisfaction were typical and expressions of remorse were uncommon. Regarding intoxicated violence as defence in response to threat, attacks were often expected, and in some cases the respondent made a pre‐emptive strike. Weapon use was common in this group. Fear was experienced, but so too was anger. Feelings of excitement were not reported and remorse was common. Further validation of these types is warranted, and the potential implications of these findings for prevention and treatment are discussed. Aggr. Behav. 36:67–79, 2010. © 2009 Wiley‐Liss, Inc.     

Covariation of self‐ and other‐directed aggression among inpatient youth: continuity in the transition to treatment and shared risk factors

Although other‐ and self‐directed aggression covary in very high‐risk youth, these forms of aggression infrequently are studied simultaneously. Understanding better their covariation is an important task for improving services to high‐risk youth. In this study, data from the clinical records of 476 youth admitted to secure inpatient treatment were analyzed to examine relations among self‐ and other‐directed aggression exhibit before and during inpatient treatment. Analyses tested the hypotheses that self‐ and other‐directed aggression would tend to covary and display continuity from pre‐treatment to in‐treatment. Also tested were the hypotheses that youth with histories of co‐occurring self‐ and other‐directed aggression would show the highest levels of aggression during treatment and the greatest degree of personal and contextual risk on entering treatment. These hypotheses were largely supported. Exploratory analyses revealed interesting discontinuities in aggression (aggression emitted only before or during treatment) with critical implications for research and practice with youth receiving clinical care, especially those in institutional placements. Aggr. Behav. 36:205–217, 2010. © 2010 Wiley‐Liss, Inc.     

Where should the balance be between “scientist” and “practitioner” in Australian undergraduate psychology?

The scientist—practitioner model of training in psychology has been widely influential in the development of undergraduate curricula in Australia. The model had its origins in post‐war America and has formed the basis for accreditation of psychology courses in Australia since the late 1970s. Recently a reconsideration of the model in Australian undergraduate psychology was argued for, suggesting that the absence of significant practical skills development in most curricula is detrimental to the discipline's graduates and their employers. The authors agree that the need for some practical skills development in undergraduate curricula is becoming increasingly important for psychology. Many of the exemplars of curriculum revision provided, however, are impractical and are unlikely to make significant contributions to Australian programs. There is an urgent need to consider the graduate attributes desired for 3‐year and 4‐year trained psychology graduates who will go on to employment without completing postgraduate study. Curriculum innovation to enhance graduates' employability will flow from this development, and will be likely to incorporate information technology solutions, rather than placement experience. This process is entirely compatible with the scientist—practitioner model of training and education in psychology.     

Race-specific perceptual discrimination improvement following short individuation training with faces

This study explores the effect of individuation training on the acquisition of race-specific expertise. First, we investigated whether practice individuating other-race faces yields improvement in perceptual discrimination for novel faces of that race. Second, we asked whether there was similar improvement for novel faces of a different race for which participants received equal practice, but in an orthogonal task that did not require individuation. Caucasian participants were trained to individuate faces of one race (African American or Hispanic) and to make difficult eye-luminance judgments on faces of the other race. By equating these tasks we are able to rule out raw experience, visual attention, or performance/success-induced positivity as the critical factors that produce race-specific improvements. These results indicate that individuation practice is one mechanism through which cognitive, perceptual, and/or social processes promote growth of the own-race face recognition advantage.     

A phase transition model for the speed-accuracy trade-off in response time experiments

Most models of response time (RT) in elementary cognitive tasks implicitly assume that the speed-accuracy trade-off is continuous: When payoffs or instructions gradually increase the level of speed stress, people are assumed to gradually sacrifice response accuracy in exchange for gradual increases in response speed. This trade-off presumably operates over the entire range from accurate but slow responding to fast but chance-level responding (i.e., guessing). In this article, we challenge the assumption of continuity and propose a phase transition model for RTs and accuracy. Analogous to the fast guess model (Ollman, 1966), our model postulates two modes of processing: a guess mode and a stimulus-controlled mode. From catastrophe theory, we derive two important predictions that allow us to test our model against the fast guess model and against the popular class of sequential sampling models. The first prediction--hysteresis in the transitions between guessing and stimulus-controlled behavior--was confirmed in an experiment that gradually changed the reward for speed versus accuracy. The second prediction--bimodal RT distributions--was confirmed in an experiment that required participants to respond in a way that is intermediate between guessing and accurate responding.     

Group identity,ethnic separatism and multiple out‐groups: The Basque case

Within the context of the Basque Country in Spain we examined how ethnic (Basque) and national (Spanish) identification relate to the evaluation of Spaniards, Basques, Andalusians and Catalans. On a sample of adolescent participants we tested a structural equation model which considered identity content (Basque separatism) as a mediator of the relationship between group identifications and group evaluations. While Spanish and Basque identification were associated with a positive evaluation of Spanish and Basque in‐groups, respectively, the evaluation of out‐groups that are relatively similar to the in‐group were not affected by identification. In contrast, dissimilar out‐groups tended to be evaluated more negatively by higher in‐group identifiers. Basque separatism mediated the negative relationship between Basque identification and the evaluation of Spaniards and of Andalusians as a prototypically Spanish subgroup. It is concluded that identification relates differently to the evaluation of different out‐groups, and that the ideological content of identity plays an important role in determining intergroup relations. Copyright © 2010 John Wiley & Sons, Ltd.