Reaction time as a function of the intensity and probability of occurrence of vibrotactile signals

Three Ss made judgments of the presence or absence of a burst of 60-cps vibration onthe index fingertip.The probability of S’s reporting the presence of a signal was found to be influenced by signal probability and signal intensity. Mean reaction time for reporting the presence of a signal decreased as a function of signal intensity and signal probability whereas mean reaction time for reporting the absence of a signal increased as a function of signal intensity and signal probability. On trials where no signal was presented mean R T for reporting a signal decreased with increases in the signal probability whereas mean RT for reporting the absence of a signal increased with increases in signal probability. The results were interpreted as support for the hypothesis that S’s decision time was longer the closer on the sensory continuum a particular observation was to his criterion.     

An examination of the effect of six types of error perturbation on fifteen clustering algorithms

An evaluation of several clustering methods was conducted. Artificial clusters which exhibited the properties of internal cohesion and external isolation were constructed. The true cluster structure was subsequently hidden by six types of error-perturbation. The results indicated that the hierarchical methods were differentially sensitive to the type of error perturbation. In addition, generally poor recovery performance was obtained when random seed points were used to start theK-means algorithms. However, two alternative starting procedures for the nonhierarchical methods produced greatly enhanced cluster recovery and were found to be robust with respect to all of the types of error examined.     

Recent developments in psychiatric malpractice

Common issues of mental health liability are examined in relationship to recent legislative and case law. Matters of practical importance to practitioners including the applicability insurance coverage to punitive damage awards of arising from malpractice are addressed. Specific legal doctrines involving proof of liability, proximate cause and the standard of care are explored as they relate to mental health malpractice cases.     

Attachment,social rank,and affect regulation: speculations on an ethological approach to family interaction

The attachment and social rank systems are biological-evolutionary systems that can serve as models for conceptualizing family interaction. By exploring both their unique and interrelated impact on affect regulation, we can differentiate between processes that foster healthy growth and those leading to individual psychopathology. This perspective facilitates the integration of biological and psychological models, and has therapeutic implications. It also integrates well with other family therapy models.     

Social problem solving and strategy use in young children

In the present study, the authors investigated what prosocial-assertive, passive, and coercive strategies 6-year-olds (N=257) would propose in response to stories about 2 socially challenging situations: displacing another child in a game and obtaining a toy from another child. The scenarios also varied the gender composition of the characters. Participants' verbalizations while acting out their responses using toy props fell into 13 categories of strategies. Teachers reported antisocial behavior and social competence of the participants. Girls and boys responded similarly in their general suggestions of prosocial or assertive strategies, but girls were more likely to offer prosocial strategies with other girls than with boys. Teacher-rated competence and antisocial behavior interacted in predicting coercive responses by girls but not by boys. The results demonstrate that prosocial and antisocial behaviors need to be considered in interaction to fully understand the nature of social competence.     

Clamped Corticosterone (B) Reveals the Effect of Endogenous B on Both Facilitated Responsivity to Acute Restraint and Metabolic Responses to Chronic Stress

To determine the effects of both corticosterone (B) and chronic stressors on acute ACTH responses to restraint, young male rats were exposed to streptozotocin-induced diabetes, cold (5-7 degreesC) or intracerebroventricular (icv) neuropeptide Y (NPY) for 5 d and then exposed to restraint within 2 h after lights on. Two groups of rats were studied: intact and adrenalectomized replaced with B pellets that maintained plasma B in the normal mean 24-h range of intact rats. In addition to ACTH and B responses to restraint on d 5, body weight, food intake, fat depots, glucose and other hormones were measured to determine the role of stress-induced elevations in B on energy balance. ACTH responses to restraint were normal in intact rats subjected to diabetes or cold. By contrast, there was no ACTH or B response to restraint in NPY-infused intact rats. All 3 groups of chronically stimulated adrenalectomized rats with clamped B had facilitated ACTH responses to restraint compared to their treatment controls. Overall food intake increased in all groups of stressed rats; however, augmented intake occurred only during the light in intact rats and equally in the light and dark in B-clamped rats. White adipose depot weights were decreased by both diabetes and cold and increased by NPY in intact rats; the decreases with cold and increases with NPY were both blunted and changes in fat stores were not significant in adrenalectomized, B-clamped rats. We conclude that: 1. diabetes- and cold-induced facilitation of restraint-induced afferent input to hypothalamic control of the hypothalamo-pituitary-adrenal (HPA) axis is opposed in intact rats by the elevated feedback signal of B secretion; 2. NPY does not induce facilitation of afferent stress pathways; 3. chronic stimulation of the HPA axis induces acute hyperresponsiveness of hypothalamic neurons to restraint provided that the afferent input of this acute stimulus is not prevented by B feedback; 4. stimulus-induced elevations in B secretion result in day-time feeding; 5. insensitivity of both caloric efficiency and white fat stores to chronic stress in adrenalectomized, B-clamped rats results from loss of normally variable B levels.     

Concomitant changes in classically conditioned heart rate and corneoretinal potential discrimination in the rabbit (Oryctolagus cuniculus)

Corneoretinal Potential (CRP) and heart rate changes were measured in a series of differential classical conditioning experiments in which the directionality of the heart rate response was related to (a) CRP acquisition, and (b) the certainty or uncertainty of the stimulus situation. The results suggested that heart rate decelerations were associated with stimuli that predict upcoming aversive events, while heart rate accelerations were associated with asymptotic CRP responding late in conditioning. These findings were interpreted in terms of (a) changes in general somatic activity, and (b) the cue properties associated with CSs which predict aversive events.     

Stages of change for health-related behaviours in 18 year-old Australians

Abstract This study investigated the validity of a Stages of Change algorithm with respect to independent measures of physical activity and fitness. dietary intake and alcohol consumption in 18 year-old Ausmlian men (n = 301) and women (n = 282). Stage of Change categories were related to fat and fibre intakes in men and fibre intake in women as well as hit and vegetable intakes in men and women. Physical activity and fitness for men and women also showed significant linear associations with Stage of Change categories. Alcohol consumption was significantly associated with Stage of Change categories for men but not for women although recorded alcohol consumption was very variable for women. However, the algorithm was valid for both men and women when drinking alcohol consistent with national guidelines on safe drinking was used. In summary, with reference to actual health behaviours, the Stages of Change algorithm was valid for young men and women for diet. physical activity and alcohol drinking. Independent behavioural data were not available for smoking behaviours. Using the algorithm, there were significant associations in men between prccontemplation status for diet and drinking and diet and physical activity, in women between diet and smoking and in both men and women between drinking and smoking. Covariance between precontemplation status for different health behaviours therefore suggests the need for multimodal interventions.     

Interactions among chronic cold, corticosterone and puberty on energy intake and deposition

We have shown that chronic cold stress strongly interacts with corticosterone (B) to determine subsequent regulation of the hypothalamo-pituitary-adrenal (HPA) axis responses to novel stress. These studies, using the same 2 sets of rats, show that chronic cold also interacts with B and testosterone on signals of energy balance. The two groups of rats differed in weight by 20% and in age by 2 weeks (44-59 days of age). Adrenalectomized rats, replaced with varying doses of B, were exposed to cold or served as controls. Food intake and body weight during the experiments and hormones, metabolites and fat depots were measured on day 5. B, but not cold, affected food intake in the younger rats; by contrast, cold, but not B, affected food intake in the older rats. Testosterone was higher in older control rats and was markedly depressed by cold; younger rats had lower testosterone that was minimally affected by cold. Weight gain decreased in all rats at room temperature with increasing B, whereas they all lost weight in cold independently of B. Cold stimulated and B inhibited interscapular brown adipose tissue DNA content (reflecting sympathetic stimulation of thermogenesis). B stimulated insulin, whereas cold inhibited leptin and insulin; B also increased white adipose tissue weight gain in controls and inhibited its loss in cold. Leptin was unrelated to white adipose tissue depots in older control rats but was strongly related to these stores in younger rats and in all rats in cold. We conclude that: 1. By decreasing signals that act centrally to inhibit food intake (insulin, leptin and testosterone) cold allows B to stimulate food intake; 2. B inhibits weight gain although it causes accrual of fat; 3. Cold, probably through sympathetic stimulation of white adipose tissue, causes fat loss which is modulated by the inhibitory effect of B on sympathetic outflow; and, 4. The slope of the relationship between fat depot size and leptin becomes flatter in cold, possibly because of increased sympathetic outflow to these depots.