A fixed interval schedule in which the interval is initiated by a response

The fixed interval schedule described requires the animal to initiate every time interval by making a response on a bar other than the one on which it is reinforced. This response, R_A, demarcates the postreinforcement pause (S^R-R_A interval) from the fixed interval pause (R_A-R_B interval) so that these pauses may be measured separately. Twelve rats and three monkeys, working in two-bar Skinner boxes, were trained and stabilized on this schedule. The resulting performances, presented for individual animals, are analyzed in terms of (1) the relative frequencies with which the animal waits various lengths of time between consecutive responses, (2) the relative frequencies with which various rates of responding appear, (3) the change in response rate throughout the fixed interval, (4) the average length of the postreinforcement pause, (5) the relative frequencies with which the animal waits different lengths of time between the R_A and the first R_B, and (6) the average inter-response time as a function of the rank order in the fixed interval of the inter-response time. The joint interpretation of the several measures taken leads to the following conclusions: 1. The probability of an R_B increases throughout the fixed interval. 2. The increase is discontinuous at the first R_B, at which point the probability increases sharply. 3. The frequency distributions of R_A-R_B pauses exhibit three discrete types of behavior with no intermediate cases. 4. The (main) mode of R_A-R_B interval length usually occurs just below the fixed interval requirement.     

The role of masculinity in a prognostic predictor of heart attack severity

Coronary heart disease (CHD) is the leading cause of mortality and morbidity in the United States for both men and women. Men, however, are more likely that women to suffer from CHD at all ages. While previous research has linked Type A behavior to CHD, investigators have failed to note the role traditional masculinity plays in the development of that behavior pattern and in the development of other psychosocial risk factors for CHD. In the present study, 90 postmyocardial infarction patients were interviewed shortly before hospital discharge. The masculinity-CHD relationship was hypothesized to be mediated by masculinity's link to Type A behavior, poor health practices, and impaired social networks. Masculinity, along with these mediating variables, was then expected to be related to the Peel prognostic indicator of heart attack severity. Results indicated that negative or extreme masculinity was related to each of the mediating variables and to heart attack severity, but the effect of masculinity on heart attack severity was not mediated by Type A behavior, poor health practices, or impaired social networks.     

Psychological and physical adjustment to breast cancer over 4 years: identifying distinct trajectories of change.

The goal of this study was to identify distinct trajectories of adjustment to breast cancer over 4 years as well as to distinguish among the different trajectories. The mental and physical functioning of 287 women with breast cancer who remained alive and disease free through 4 years of follow-up were examined. The majority of women showed slight and steady improvement in functioning with time, but subgroups of women were identified who showed marked improvement and marked deteriorations over time. Age successfully distinguished different trajectories of physical functioning. Indices of personal resources (i.e., self-image, optimism, perceived control) and social resources (i.e., social support) successfully distinguished different courses of mental and physical functioning.     

Post-concussive Signs and Symptoms in Preschool Children: A Systematic Review

Neuropsychology Review - Mild traumatic brain injury (mTBI) is common in children aged?<?5 years, however, less is known about their experience of post-concussive signs...     

An Exploration of Families' Psychosocial Well-Being in a South African Context

The aim of this study was to explore and describe aspects that contribute to the psychosocial well-being of families from diverse cultures in a South African context by analysing data obtained through narratives, drawings and interviews with families. Participant families took part voluntarily in family interviews (N=36), written narratives (N=23) and drawings (N=14). These different methods of data collection provided rich data on family psychosocial well-being in a South African context with culturally diverse families, as well as on those aspects that influence family psychosocial well-being. The findings suggest that communication, mutual support, togetherness as a family and spirituality are the most prominent contributing factors, while financial difficulties and interpersonal conflicts or arguments are the most prominent hindering factors with regard to family psychosocial well-being in this group of participants.     

Obsessive-compulsive disorder symptoms and correlates in community exercisers

ObjectivesThe purpose of this study was to examine the potential relationship between OCD symptoms and the constructs of depression, anxiety, self-esteem, and commitment to exercise in community-based exercisers.Design and methodA mixed-methods approach was utilized. A sample of 64 female and 21 male participants (M age = 52.1 years) completed a series of online or written questionnaires related to the noted variables, while a subset of 10 participants participated in a qualitative interview to explain their OCD symptoms and exercise behavior.ResultsPearson correlations indicated all psychological constructs were significantly correlated with each other (absolute r's ranged from .27 to .78, all p's < .001), while a canonical correlation analysis revealed one significant function (Wilk's λ = .360, R_c = .80, p < .001). Set 1 (OCD symptoms) explained 36% of the variance in Set 2 (anxiety, depression, self-esteem and commitment to exercise), while Set 2 explained 64% of the variance in Set 1. Four primary themes were established from the qualitative data, including: 1) being involved in sport or physical activity from a young age, 2) high benefits versus low consequences of regular participation in exercise, 3) involvement in detail-oriented jobs, and 4) easy adjustments to unplanned deviations from an exercise schedule.ConclusionsOverall, this research suggests that community-based exercisers with elevated OCD symptoms simply display a healthy attention to the frequency and detail of their physical activity, which facilitates them staying active across a variety of conditions.     

Planning and Problem Solving Skills Following Focal Frontal Brain Lesions in Childhood: Analysis Using the Tower of London

Problem solving skills were investigated in children with focal lesions using the Tower of London test (TOL; Shallice, 1982). The scoring procedure was elaborated from previous studies to delineate separate processes contributing to overall performance in children. Thirty-one children with focal frontal pathology, 18 children with focal pathology in other brain regions (extra-frontal), 17 children with generalized pathology and 38 healthy children participated in the study. Results suggest a distributed network for problem solving skills, particularly cognitive flexibility and goal setting skills. Within the frontal group, children with lesions involving the right pre-frontal cortex had greatest problems with self-regulation, with rule breaks most common among this group. As these skills develop relatively early in comparison to other aspects of executive function, right pre-frontal regions may play a particularly important role in the development of executive skills in childhood, with damage to these regions rendering children vulnerable to a range of cognitive and social deficits.     

Impairments of Attention Following Childhood Traumatic Brain Injury

Attentional deficits are commonly reported following traumatic brain injury (TBI) in adults, although the occurrence of such problems is less well documented in young children. This study aimed to investigate residual attentional abilities associated with TBI during childhood, by examining a number of aspects of attention including sustained, focussed, and divided attention, attentional shift, and response inhibition. Eighteen children with a history of TBI, aged between 8 and 14 years and 18 non-injured matched controls participated in the study. Results show that attentional skills may be differentially impaired after TBI, with children who have sustained moderate-to-severe TBI exhibiting significant deficits on the following attentional domains: sustain, focus, and response inhibition. These findings support the view that attentional impairments following pediatric TBI, while not global, may be more generalized than those reported for adult samples, perhaps reflecting the relative immaturity of attentional skills at the time of injury.