Effects of cocaine on briefly signaled versus completely signaled delays to reinforcement.

Key pecking by 4 pigeons was maintained by a multiple schedule consisting of two variable-interval 60-s schedules wherein each food presentation followed a nonresetting 27-s delay that was either briefly signaled at its outset or completely signaled. Brief-signal duration was adjusted so that response rates maintained by the briefly and completely signaled delays of reinforcement were similar. In general, acute administration of small to intermediate doses (0.3 to 3.0 mg/kg) of cocaine produced either small increases in response rates in both components or no change, and larger doses (5.6 to 13.0 mg/kg) decreased response rates. Chronic (i.e., daily) cocaine administration (10.0 mg/kg) resulted in tolerance to the rate-decreasing effects in both components. Cocaine's effects were generally similar whether delays were completely or briefly signaled. Discontinuation of cocaine administration and subsequent removal of the delay signals also had similar effects in both components of the multiple schedule. Taken together, these results are consistent with the view that the two types of delay signals were equally effective in maintaining responding during the variable-interval schedules.     

Tolerance to and residual effects of cocaine in squirrel monkeys depend on reinforcement-schedule parameter.

Lever pressing by 4 squirrel monkeys was maintained under a three-component multiple fixed-ratio schedule of food presentation; components differed with respect to ratio size. For each monkey, acute administration of cocaine (0.03 to 1.3 mg/kg, i.m.) produced dose-dependent decreases in overall response rate in each component. During repeated daily administration of 1.0 mg/kg of cocaine, tolerance developed to the rate-decreasing effects under each of the ratio contingencies, but developed to a greater extent and was evident in earlier parts of sessions for performance under the smaller ratios. Response rates of 2 monkeys increased above nondrug control levels despite the putative reinforcer not being consumed during the session. When saline or a smaller dose of cocaine was substituted for 1.0 mg/kg, response rates often were suppressed below nondrug control-level responding. This suppressive effect was observed in each monkey and was more likely to be observed and/or to be of greater magnitude in large-ratio components for 3 of the 4 monkeys. When saline was administered chronically at the end of the chronic-drug phase, response rates remained suppressed in the large-ratio component for 2 of the monkeys. There was, therefore, a schedule-dependent dissociation between behavioral tolerance and the residual effects: Tolerance was greater when small ratios were arranged, whereas the residual effects were more pronounced when larger ratios were arranged.     

Fighting experiences and natural killer cell activity in male laboratory mice

There is currently much interest in the potential impact of psychological factors on immune responses. An attempt was made to assess the effects of dominant/subordinate polarity in male mice on the cytotoxic activities of their natural-killer (NK) cells. On the basis of repeated agonistic encounters, categories of subordinate and dominat animals were selected. These animals were compared with manipulated controls (introduced to a novel test cage without an opponent on each occasion) and undisturbed controls (who remained in isolation without manipulation). In terms of NK activity, immunosuppression was observed in both dominant and subordinate categories when compared to undisturbed controls. There were, however, no differences between the fighting exposed subjects and the manipulated controls, suggesting that stress accounts for any changes. © 1994 Wiley-Liss, Inc.     

Providing noncontingent,alternative, functional reinforcers during delays following functional communication training

Functional Communication Training (FCT) involves arranging extinction for problem behavior and reinforcement for a more desirable, functionally equivalent, communicative response (FCR). Although effective under ideal arrangements, the introduction of delays to reinforcement following the FCR can result in increased problem behavior. Austin and Tiger (2015) showed that for individuals whose problem behavior was sensitive to multiple sources of reinforcement, providing access to alternative, functional reinforcers during delays mitigated this increase in problem behavior during delay fading. The current study replicated the procedures of Austin and Tiger with 2 individuals displaying multiply controlled problem behavior. Providing alternative functional reinforcers reduced problem behavior during 10-min delays for both participants without requiring delay fading.     

Distancing or drawing together: Sexism and organisational tolerance of sexism impact women's social relationships at work

This article examines the role of organisational climate in women's social responses to sexism at work. We argue that after experiences of sexism, women “draw together” with other women when they perceive that the organisational climate is intolerant of sexism. We assess the role of organisational climate at three levels: peer-, manager-, and policy-level. We conducted a correlational study (N_study1 = 405) and two experimental studies (N_study2 = 377, N_study3 = 391), in which we examined women's experiences of sexism at work (measured in Study 1; manipulated in Studies 2 and 3). We also measured perceived tolerance of sexism at the peer-, manager- and policy-level in all studies. The main DVs were women's workplace friendships with other women in Studies 1 and 2, and closeness to female co-workers in Study 3. Results showed that perceived tolerance of sexism from peers was especially important in shaping women's social relationships following experiences of sexism; tolerance from managers or at the policy level had less consistent effects. Specifically, experiences with sexism were positively associated with female participants' reported friendship (Studies 1 and 2) and closeness (Study 3) with their female colleagues, but only when peers were perceived not to tolerate sexism. When peers were perceived to tolerate sexism, female participants did not respond to sexism by drawing together.     

MORPHINE TOLERANCE AS A FUNCTION OF RATIO SCHEDULE: RESPONSE REQUIREMENT OR UNIT PRICE?

Key pecking by 3 pigeons was maintained by a multiple fixed-ratio 10, fixed-ratio 30, fixed-ratio 90 schedule of food presentation. Components differed with respect to amount of reinforcement, such that the unit price was 10 responses per 1-s access to food. Acute administration of morphine, l-methadone, and cocaine dose-dependently decreased overall response rates in each of the components. When a rate decreasing dose of morphine was administered daily, tolerance, as measured by an increase in the dose that reduced response rates to 50% of control (i.e., the ED50 value), developed in each of the components; however, the degree of tolerance was smallest in the fixed-ratio 90 component (i.e., the ED50 value increased the least). When the l-methadone dose-effect curve was redetermined during the chronic morphine phase, the degree of cross-tolerance conferred to l-methadone was similar across components, suggesting that behavioral variables may not influence the degree of cross-tolerance between opioids. During the chronic phase, the cocaine dose-effect curve shifted to the right for 2 pigeons and to the left for 1 pigeon, which is consistent with predictions based on the lack of pharmacological similarity between morphine and cocaine. When the morphine, l-methadone, and cocaine dose-effect curves were redetermined after chronic morphine administration ended, the morphine and l-methadone ED50s replicated those obtained prior to chronic morphine administration. The morphine data suggest that the fixed-ratio value (i.e., the absolute output) determines the degree of tolerance and not the unit price.     

Distress tolerance but not impulsivity predicts outcome in concurrent treatment for posttraumatic stress disorder and substance use disorder

Posttraumatic stress disorder (PTSD) and substance use disorder (SUD) commonly co-occur. Emerging research suggests that both distress tolerance and impulsivity may underlie this comorbidity. However, to our knowledge no studies have examined whether these 2 constructs predict outcome in PTSD-SUD treatment. The current study investigated whether pretreatment distress tolerance and impulsivity predicted posttreatment PTSD and cravings severity in a sample of 70 Veterans receiving concurrent treatment for PTSD and SUD in a residential day treatment program. Veterans completed measures of symptom severity before and after treatment. Results demonstrated that pretreatment distress tolerance predicted posttreatment PTSD severity while controlling for pretreatment PTSD. By contrast, pretreatment impulsivity was not predictive of posttreatment PTSD while controlling for pretreatment values. Neither distress tolerance nor impulsivity predicted posttreatment cravings severity. The findings support the notion that distress tolerance may help to explain the co-occurrence of PTSD and SUD and suggest that targeting this construct in PTSD-SUD treatment may be important for successful outcomes.     

行为免疫系统对个体就医行为倾向的影响

研究首次考察了行为免疫系统与个体就医行为倾向的关系。3个研究一致显示：行为免疫系统特质性激活水平较高的个体更容易对就医持消极态度和延迟就医; 情境性激活行为免疫系统会使得个体更不愿意就医和更倾向于延迟就医; 且行为免疫系统激活对就医态度和就医延迟倾向的影响以对就医感染风险的感知为中介。这支持了进化失配假说, 提示行为免疫系统对现代医学可能缺乏进化的适应性, 并为理解现代人类就医行为提供了新的理论视角。     

Altering Impulsive Decision Making With an Acceptance-Based Procedure

Delay discounting is one facet of impulsive decision making and involves subjectively devaluing a delayed outcome. Steeply discounting delayed rewards is correlated with substance abuse and other problematic behaviors. To the extent that steep delay discounting underlies these clinical disorders, it would be advantageous to find psychosocial avenues for reducing delay discounting. Acceptance-based interventions may prove useful as they may help to decrease the distress that arises while waiting for a delayed outcome. The current study was conducted to determine if a 60–90 minute acceptance-based training would change delay discounting rates among 30 undergraduate university students in comparison to a waitlist control. Measures given at pre- and posttraining included a hypothetical monetary delay discounting task, the Acceptance and Action Questionnaire-II (AAQ-II), and the Distress Tolerance Scale. Those assigned to the treatment group decreased their discounting of delayed money, but not distress intolerance or psychological inflexibility when compared to the waitlist control group. After the waiting period, the control group received the intervention. Combining all participants’ pre- to posttreatment data, the acceptance-based treatment significantly decreased discounting of monetary rewards and increased distress tolerance. The difference in AAQ-II approached significance. Acceptance-based treatments may be a worthwhile option for decreasing delay discounting rates and, consequently, affecting the choices that underlie addiction and other problematic behaviors.     

Children's Sensitivity to Cost and Reward in Decision Making across Distinct Domains of Probability,Effort, and Delay

Many behavioral paradigms used to study individuals' decision‐making tendencies do not capture the decision components that contribute to behavioral outcomes, such as differentiating decisions driven toward a reward from decisions driven away from a cost. This study tested a novel decision‐making task in a sample of 403 children (age 9 years) enrolled in an ongoing longitudinal study. The task consisted of three blocks representing distinct cost domains (delay, probability, and effort), wherein children were presented with a deck of cards, each of which consisted of a reward and a cost. Children elected whether to accept or skip the card at each trial. Reward–cost pairs were selected by using an adaptive algorithm to strategically sample the decision space in the fewest number of trials. Using person‐specific regression models, decision preferences were quantified for each cost domain with respect to general tolerance (intercept), as well as parameters estimating the effect of incremental increases in reward or cost on the probability of accepting a card. Results support the relative independence of decision‐making tendencies across cost domains, with moderate correlations observed between tolerance for delay and effort. Specific decision parameters showed unique associations with cognitive and behavioral measures including executive function, academic motivation, anxiety, and hyperactivity. Evidence indicates that sensitivity to reward is an important factor in incentivizing decisions to work harder or wait longer. Dissociating the relative contributions of reward and cost sensitivity in multiple domains may facilitate the identification of heterogeneity in suboptimal decision making. Copyright © 2017 John Wiley & Sons, Ltd.