Sensitivity to reinforcer duration in a self-control procedure

In a concurrent-chains procedure, pigeons' responses on left and right keys were followed by reinforcers of different durations at different delays following the choice responses. Three pairs of reinforcer delays were arranged in each session, and reinforcer durations were varied over conditions. In Experiment 1 reinforcer delays were unequal, and in Experiment 2 reinforcer delays were equal. In Experiment 1 preference reversal was demonstrated in that an immediate short reinforcer was chosen more frequently than a longer reinforcer delayed 6 s from the choice, whereas the longer reinforcer was chosen more frequently when delays to both reinforcers were lengthened. In both experiments, choice responding was more sensitive to variations in reinforcer duration at overall longer reinforcer delays than at overall shorter reinforcer delays, independently of whether fixed-interval or variable-interval schedules were arranged in the choice phase. We concluded that preference reversal results from a change in sensitivity of choice responding to ratios of reinforcer duration as the delays to both reinforcers are lengthened.     

儿童拒绝敏感性与自我知觉的关系:一项交叉滞后研究

采用儿童拒绝敏感性问卷与儿童自我知觉量表对596名中小学儿童进行了为期一年的追踪调查,通过交叉滞后回归分析考察儿童拒绝敏感性与多种自我知觉间的预测关系。结果发现：（1）自我知觉的年级差异显著,初中儿童的自我知觉水平较低;（2）在两次测量中,拒绝敏感性与多种自我知觉均呈显著的负相关;（3）控制性别、年级以及自身稳定性之后,第一年的多种自我知觉均可以负向预测第二年的拒绝敏感性,而第一年的拒绝敏感性仅可以负向预测第二年的体貌及一般自我知觉;（4）年级调节了拒绝敏感性与一般和行为自我知觉间的纵向关系,并在小学与初中儿童中表现出不同的模式。研究证实自我知觉是儿童拒绝敏感性形成的重要原因之一,为儿童社会认知及心理健康的相关研究提供新的实证依据。     

Rat choice in rapidly changing concurrent schedules

In two experiments, experimentally naïve rats were trained in concurrent variable‐interval schedules in which the reinforcer ratios changed daily according to a pseudorandom binary sequence. In Experiment 1, relative response rates showed clear sensitivity to current‐session reinforcer ratios, but not to previous sessions' reinforcer ratios. Within sessions, sensitivity to the current session's reinforcement rates increased steadily, and by session end, response ratios approached matching to the current‐session reinforcer ratios. Across sessions, sensitivity to the current session's reinforcer ratio decreased with continued exposure to the pseudorandom binary sequence, contrary to expectations based on previous studies demonstrating learning sets. Using a second group of naïve rats, Experiment 2 replicated the main results from Experiment 1 and showed that although there were increases over sessions in both changeover rate and response rate during the changeover delay, neither could explain the accompanying reductions in sensitivity. We consider the role of reinforcement history, showing that our results can be simulated using two separate representations, one local and one nonlocal, but a more complex approach will be needed to bring together these results and other history effects such as learning sets and spontaneous recovery.     

Loneliness,HPA stress reactivity and social threat sensitivity: Analyzing naturalistic social challenges

Loneliness has been linked to poor health through an increased activation of threat surveillance mechanisms, such as the hypothalamic‐pituitary‐adrenal axis (HPA ). The socio‐cognitive model (Cacioppo & Hawley) proposes that lonely people have an increased social threat sensitivity which activates the HPA axis. The current study examined the impact of loneliness on HPA stress reactivity and social threat sensitivity in response to naturally occurring social challenges. Participants (N = 45) were prospective undergraduates attending a 3‐day university preparation programme over the summer, prior to commencing their university studies. Cortisol levels and perceived stress were measured before and after an ice breaker session on Day 1 and a lecture session on Day 3. Social threat sensitivity was also measured on the first and third day. When meeting unfamiliar peers in the ice breaker session, HPA stress reactivity was evident, but it was not markedly different in those who reported high levels of loneliness than those with low levels. The high loneliness group had higher levels of perceived stress and increased social threat sensitivity than the low loneliness group on both testing days. The findings show partial support for the socio‐cognitive model of loneliness because increased threat sensitivity was demonstrated in the high loneliness group. The findings indicate that lonely people do not respond in a physiologically different way to specific social challenges, but they typically report higher social threat sensitivity and higher perceived stress than their non‐lonely peers.     

MEDIATING ROLE OF MATERNAL SENSITIVITY: ENHANCING LANGUAGE DEVELOPMENT IN AT‐RISK FAMILIES

Home‐visiting programs have gained increasing importance in family‐centered prevention and intervention. However, few studies have examined the mechanisms underlying early intervention treatment effects. The goal of this study is to analyze the mediating role of maternal sensitivity in enhancing language development with the home‐visiting program Parents as Teachers (PAT). Data were collected and analyzed within the ongoing, long‐term ZEPPELIN study, a randomized controlled trial with 251 participating at‐risk families. Via longitudinal mediation analysis, we examined whether effects of the PAT on receptive and expressive language outcomes at 24 and 36 months were mediated by maternal sensitivity at 12 months. Within a moderated mediation framework, we investigated whether the level of family psychosocial stress affects this mediation. Results showed that intervention effects on language outcomes are mediated by maternal sensitivity—weakly and through specific pathways. Moderation and moderated mediation analyses indicated that effects of the PAT and also specific mediation effects increase with the level of psychosocial stress. Implications of the results for practice are discussed.     

Body Mass Index and functional impairment: the explanatory role of anxiety sensitivity among treatment-seeking smokers

Obesity and smoking are highly prevalent public health concerns in the United States. Data indicate that elevated Body Mass Index (BMI) is related to functional impairment. However, there is limited understanding of mechanisms that may explain their comorbidity among smokers. The current study sought to test whether anxiety sensitivity explained the relation between BMI and functional impairment among 420 (46.9% females; M_age = 38 years, SD = 13.42) treatment-seeking, adult smokers. Results indicated that BMI yielded a significant indirect effect through anxiety sensitivity for functional impairment, b = 0.01, SE = .01, 95% CI = [.002, .021]. These findings remained significant after controlling for participant sex, negative affectivity, tobacco dependence, psychopathology, and medical conditions (i.e. hypertension, heart problems, respiratory disease, asthma). Such data provide novel empirical evidence that, among smokers, BMI may be a risk factor for functional impairment indirectly through anxiety sensitivity. Overall, such findings could potentially inform the development of personalized interventions among this particularly vulnerable segment of the smoking population.     

Anxiety sensitivity moderates the painful effects of feeling burdensome to others

Perceived burdensomeness (PB), the perception of being a burden to others, is associated with pain and physical symptoms. Anxiety sensitivity (AS), the fear of arousal-related sensations, arising from beliefs that the sensations may have adverse personal consequences (physical, cognitive, and social), may increase risk for pain responding, particularly in anxiety-provoking (e.g. socially threatening) contexts. Accordingly, individuals high in AS may have a stronger pain response when experiencing PB than those low in AS. Undergraduate participants (n = 262) completed the Anxiety Sensitivity Index (ASI-3), and then were randomly assigned to re-live an experience when they were either burdensome to others (burdensome condition) or contributed equally to a group (control condition). Both social and physical self-reported pain were assessed post-manipulation. Those high in AS reported significantly higher pain ratings in the burdensome condition than the control condition; for those low in AS, pain did not change across conditions. In particular, being fearful of the physical repercussions of anxiety (AS physical concerns) while also feeling burdensome to others was associated with greater physical pain. AS may exacerbate the already painful effects of feeling burdensome to others, and may have important implications for the development of future suicide- and pain-related interventions.     

Conscious and unconscious discriminations between true and false memories

When subjects give higher confidence or memory ratings to a test word in a recognition test, do they simply raise their criterion without making better discrimination, or do they raise both criterion and true discrimination between the studied words (SW) and the lures? Given that previous studies found subjects’ false alarm responses to lures slower than to SW, and recognition latency inversely correlated with the confidence rating, can the latency difference between the lures and SW be accounted for by confidence or memory ratings? The present results showed that when subjects gave higher confidence or memory ratings, both their bias and sensitivity were raised, indicating that they could consciously distinguish the lures from the SW. However, a latency difference between true and false recognitions persisted after confidence and memory ratings were held constant, suggesting an unconscious source of discrimination between the two types of memory.