Instrumental responding by rats on free-operant schedules with components that schedule response-dependent reinforcer omission: Implications for optimization theories

In two experiments, we assessed whether rats optimize the number of reinforcers per response. In Experiment 1, one group of rats was trained to leverpress for food reinforcement on a simple variable-interval (VI) 60-sec schedule. For another group, a negative fixed-ratio component was imposed on the VI schedule to produce a conjoint contingency in which reinforcement became available on the VI schedule but was omitted when the ratio criterion was satisfied. In Experiment 2, one group of rats responded on a VI schedule and also received response-independent food. For another group, responding above a certain rate canceled the response-independent food. Despite the negative contingency experienced by the groups in Experiments 1 and 2, responding was maintained at a level at which the number of obtained reinforcers was reduced substantially below the maximum number possible. In addition, in both experiments, the groups that experienced the negative contingency responded at a lower rate than did a yoked control group that experienced the same frequency of reinforcement but lacked the negative component. These results demonstrate that although rats do not optimize their behavior with respect to reinforcement, they are nevertheless sensitive to some aspect of the instrumental contingency in operation.     

Addressing the ‘elephant in the room’. The role of the primary school practitioner in supporting children’s mental well-being

The enthusiasm regarding the school as a place for mental health promotion is powered by a large body of research demonstrating the links between mental health and well-being, academic success and future life opportunities. Despite on-going commitment to mental well-being in the U.K., statistics suggest mental health issues are increasing among children and young people. This small-scale qualitative-exploratory study, undertaken in two primary schools in North Wales, reports on how school practitioners perceive, promote and support the mental health and well-being of pupils. The paper highlights a reluctance by practitioners to address mental health topics due to fear of stigma and a desire to protect children. Issues linked to funding, skills and training, together with over-stretched specialist agencies, are making it difficult for school practitioners to support pupils. There is a pressing need for appropriate training opportunities in order for practitioners to be knowledgeable and to feel confident to discuss mental health with children and young people. Schools have a significant role in supporting children’s mental well-being and reducing the stigma attached to mental illness but only if this important topic is not regarded as an ‘elephant in the room’.     

The use of the intensity gradient and average acceleration metrics to explore associations with BMI z-score in children

ABSTRACT

This study used the intensity gradient (IG) and average acceleration metrics to describe children’s activity profiles and explore associations with body mass index (BMI) z-score. Two hundred and forty-six children (n = 138 girls) aged 9.6 ± 1.4 years wore a wrist-mounted ActiGraph wGT3X-BT accelerometer for 7 days on their non-dominant wrist. Physical activity (PA) metrics captured included: the IG which describes the intensity distribution of accelerations across the 24 h monitoring period; average acceleration which provides a measure of the volume of activity; total moderate-to-vigorous PA (MVPA) and inactive time. Acceleration was averaged over 5s epochs. Finally, BMI z-score was calculated for each participant. Average acceleration was negatively associated with BMI z-score (p < 0.05) independent of age and gender but not IG. The IG was negatively associated with BMI z-score independent of potential correlates and average acceleration. Total MVPA was not associated with BMI-z score. The IG and average acceleration metrics may be used to explore the independent or cumulative effects of the volume and intensity distribution of activity upon measures of health and well-being in children to inform specific activity recommendations.