Leverpress escape/avoidance conditioning in rats: Safety signal length and avoidance performance

Leverpress escape/avoidance is an excellent model for assessing coping in rats. Acquisition of the leverpress response is determined by the interstimulus (signal-shock) interval, as well as the type and duration of the aversive event. One factor that has received less research attention is the safety or feedback signal. The safety signal presumably negatively reinforces leverpress responding through fear reduction. Here, we present a parametric manipulation of safety signal length and avoidance performance. All rats were trained with a 60-s tone conditioned stimulus and an intermittent 1-s, 1.0-mA footshock. Training was further accomplished with a 1−, 2−, 4−, or 6-min safety signal. Acquisition of the avoidance response was comparable at all safety signal durations. Rats trained with the shortest safety signal (1 min) exhibited more leverpresses during the safe period, a measure of anxiety. Thus, acquisition of the leverpress avoidance response was efficient regardless of safety signal duration, even though shorter periods were associated with greater anxiety.     

Adolescent well‐being and supporting contexts: A comparison of adolescents in Ireland and Florida

The purpose of this research was to examine the extent to which social support and wider community perceptions/engagements among adolescents are connected with well‐being. We compared adolescents in two different societal contexts, Florida in the United States and County Offaly, in Ireland, and posed the questions: What are the key predictors of subjective well‐being from the various sources of support, and to what extent does the impact of social support on well‐being vary across these two societies? Questionnaires were completed and returned for 607 respondents (322 in the Irish study and 285 in the Florida study). A variety of scales were adopted and designed to operationalize our key concepts of: Adolescent well‐being, social support, school satisfaction, neighbourhood quality of life and community/voluntary participation. Our results indicate that informal social support and school satisfaction were the strongest predictors of youth well‐being in both locations, despite some differences in terms of individual influencing variables. From informal sources, emotional support from friends and advice/concrete/esteem support from parents emerged as important predictive dimensions. Liking school, perceptions of doing well in school were the main predictors of school satisfaction in Ireland while, in Florida, student camaraderie and the experience of bullying emerged as significant. Copyright © 2009 John Wiley & Sons, Ltd.     

A Social Disorganization Perspective on Bullying-Related Attitudes and Behaviors: The Influence of School Context

Social disorganization theory suggests that certain school-level indictors of disorder may be important predictors of bullying-related attitudes and behaviors. Multilevel analyses were conducted on bullying-related attitudes and experiences among 22,178 students in 95 elementary and middle schools. The intraclass correlation coefficients indicated that 0.6–2% of the variance in victimization, 5–10% of the variance in retaliatory attitudes, 5–6% of the variance in perceptions of safety, and 0.9% of the variance in perpetration of bullying was associated with the clustering of students within schools. Although the specific associations varied somewhat for elementary schools as compared to middle schools, the hierarchical linear modeling analyses generally suggested that school-level indicators of disorder (e.g., student–teacher ratio, concentration of student poverty, suspension rate, and student mobility) were significant predictors of bullying-related attitudes and experiences. Student-level characteristics (i.e., sex, ethnicity, status in school) were also relevant to students’ retaliatory attitudes, perceptions of safety, and involvement in bullying. Implications for school-based research and violence prevention are provided.     

Age differences in within-session habituation of exploratory behavior: effects of stimulus complexity

The effects of age on the habituation of exploratory behavior of 8-month- and 28-month-old male C57BL/NNia mice were examined under three different stimulus complexity conditions. Increases in the degree of stimulus complexity resulted in an attenuation of between-session habituation and an initial disruption of within-session habituation by 8-month-old mice. Although increases in stimulus complexity also resulted in an increase in the overall level of exploration by aged mice, stimulus complexity was not found to have a systematic effect on between- or within-session habituation by aged mice. No between-session habituation was observed in aged mice under any of the stimulus complexity conditions. Further, aged mice exhibited significant within-session increases, rather than decreases, in exploration under each stimulus complexity condition. This disruption of within-session habituation in aged mice was found to persist over four daily test sessions. In view of the specific patterns of exploration by aged mice, the disruption of within-session habituation was attributed to age-related differences in reactivity to the arousal-inducing properties of novel stimuli.     

CONDITIONING MODELS OF ANXIETY

A critical examination is made of some behavioristic conceptualizations and treatments of chronic anxiety which are mostly based on a classically-conditioned fear model. A new model is proposed wherein it is assumed that tonic emotional states such as anxiety are more based on instrumental conditioning. This model has been successfully tested in experiments with monkeys. Questions remain about the relevance of this model with regard to the natural actual life etiology of these disorders.