An analysis of response,direction, and place learning in an open field and T maze

Rats were trained to locate food in a response, direction, or place problem on an open field located at 2 positions. In Experiment 1, both the response and direction groups solved the problem. The place group failed to solve the task in approximately 300 trials. Experiment 2 demonstrated that rats need distinguishable start points to solve a place problem when neither a response nor a direction solution is available. Findings from Experiment 3 suggest that a combination of path traveled and distinct cues help to differentiate start points. Experiment 4 replicated the findings using a T maze. These results suggest "place" solutions are difficult for rats. The data are discussed with respect to conditional learning and modern spatial mapping theory.     

Birth order effects in dominance: failure to support Sulloway's view

Contrary to Sulloway's 1996 assertion that firstborns should score higher than laterborns on measures of dominance, the dominance scores for 76 firstborn undergraduate students (50 women, 26 men) did not differ significantly from the scores of 75 laterborn students (48 women, 27 men) on the 16PF dimension of Dominance vs Submissiveness (Factor E). Further research into possible differences in performance strategies between laterborns and firstborns in childhood vs adulthood is necessary to evaluate Sulloway's theory of ordinal position definitively.     

Effects of Interspersing Additional Brief Math Problems on Student Performance and Perception of Math Assignments: Getting Students to Prefer to Do More Work

Three experiments were conducted to assess the effects of the interspersing procedure on students' mathematics performance, perceptions of mathematics assignments, and preference for mathematics assignments when more work was added. In Experiment I, college students worked computation problems from two assignments. The control assignment contained 15 three-digit by two-digit problems (3 × 2) and the experimental assignments contained 18 3 × 2 problems and 6 additional interspersed one-digit by one-digit problems (1 × 1). Students then rated the assignments and chose one for homework. Results showed significantly more students preferred (i.e., chose it for homework) the experimental assignment with the additional target (i.e., 3 × 2) and interspersed problems. Furthermore, significantly more students rated this experiment as requiring less effort and being less difficult. Moreover, students' mathematics performance was not affected by the procedure. Experiment II strengthened the internal validity by showing that students did not prefer the experimental assignment because it contained more target problems. Experiment III showed that the interspersing procedure was not powerful enough to extend findings beyond the 20% level (i.e., 40 and 60% more conditions). Results showed how the interspersing procedure could be used to encourage students to choose to do more target computation tasks. Discussion focuses on the applied value of the interspersing procedure and plausible causal mechanisms that may account for current and past findings related to student choice and interspersing brief tasks.     

The duration and perceived intensity of sucrose taste

Thirty-two subjects judged the perceived intensity of each of four concentrations of sucrose over 2 min. Stimuli were either sipped and expectorated or flowed over the subject’s extended tongue. Ratio judgments on a line scale and category ratings were made. Sixteen of the subjects had had extensive training in judging the sensory attributes of food products, and another group of 16 subjects were untrained. The perceived intensity of sucrose rose to a peak within 5 or 10 sec, and then declined over 2 min. In both the sip and the flow conditions, the taste disappeared completely for 26 of 32 subjects. Stronger concentrations were perceived as having greater peak intensities and longer lasting taste. The differences between concentrations were enhanced when sipped rather than flowed over the tongue. Judgments of intensity and duration were largely unaffected by the training level of subjects and the use of different rating scales.     

Neurocardiology shows that the central,not peripheral,action of propranolol reduces mortality following acute coronary artery occlusion in the conscious pig

Neurocardiology emphasizes the role of the higher cerebral mechanisms in cardiovascular disorders. Several large clinical trials (BHAT, MIAMI, and ISIS) have consistently shown that treatment with a beta-receptor blocker (propranolol, metoprolol, or atenolol) will produce a 26% to 29% reduction in mortality in high-risk survivors of acute myocardial infarction. Becauseall beta-blockers cross the blood-brain barrier, it is not clear whether the salutary action is on the central or peripheral receptors. Therefore the effects of intracerebral versus intravenous propranolol were observed in 30 conscious pigs following complete occlusion of the left anterior descending coronary artery. Controls showed the propranolol to remain confined throughout the experiment to the central or peripheral compartment into which it was injected. To assure the occurrence of ventricular fibrillation (VF), each pig was psychologically stressed by being unconditioned to the laboratory.Intracerebral propranolol (0.05 mg/kg) prevented VF within a 20 min period of reversible ischemia in 6 of 9 pigs, whereas VF was prevented in 0 of 11 controls injected intravenously with either dextro-propranolol (2 pigs) or vehicle (9 pigs) (P<.0006, binomial probability ratio). In some pigs in which VF was not manifested by 20 min, the ischemia was reversed and additional control observations were achieved; a total of 10 counter-balanced within-subjects experiments confirmed the between-subjects result (P<.01, paired-t test). In contrast intravenous propranolol (0.2 to 2.0 mg/kg) in 7 pigs had no effect on VF latency compared to 7 vehicle controls. It is concluded that beta-receptor antagonists prevent VF in the ischemic myocardium by their effect on thebrain andnot the heart.     

Sociocultural studies of families of children with intellectual disabilities

This article reviews recent sociocultural studies of families of children with intellectual disabilities to introduce the range of research conducted from this perspective and to highlight the methodological, conceptual, and theoretical contributions of this approach to the study of mental retardation. Sociocultural studies examine families within their cultural, historical, and sociopolitical contexts. This type of research is comparative across different cultural groups, but is not limited to such comparisons. Sociocultural studies use varied theories and methods, but they share a focus on families' coproduction of meanings and practices related to intellectual disability; families' responses and adaptations to disability; and how their understandings and experiences are shaped within larger social institutions and inequities. Sociocultural approaches take into account community contexts that matter to families with members with mental retardation or developmental delay, and they examine the broader systems that define and position individuals with disabilities and their families. As a whole, these studies provide a more experiential and holistic view of families' beliefs and adaptations within sociopolitical worlds, and offer new tools by which to study the families of children with developmental delays within and across different cultural groups.     

Location serves as a conditional cue when harp seals (Pagophilus groenlandicus) solve object discrimination reversal problems.

We examined the capacity of harp seals (Pagophilus groenlandicus) to use spatial context (i.e., their tank) as a conditional cue to solve a two-choice visual discrimination reversal task. Seals were trained to touch one of two 3D objects. Two of four seals experienced a context shift that coincided with each of five reversals in the reward value of the two stimuli (i.e., a reversal of S+ and S-); these seals solved the six discriminations in significantly fewer trials than did seals that did not experience a context shift with the contingency reversal. Thus, harp seals use contextual cues when encoding information. The findings are discussed in terms of harp seals' adaptations to the pack-ice environment, the constraints of the learning tasks, and the nature of the subjects that were raised in captivity.     

Stigma and Discrimination in Health-Care Provision to Drug Users: The Role of Values, Affect, and Deservingness Judgments

This study examined the role of values, affect, and deservingness judgments in health professionals' views of patients with stigmatized conditions (e.g., drug dependence). Participants were 277 nurses who responded to a survey containing 2 scenarios of a nurse providing high- or low-quality care to a patient with a condition related to prolonged use of alcohol or heroin. Affective responses to the patient were more positive for nurses with higher self-transcendence values, and more negative for nurses with higher conservation values. Deservingness judgments were predicted by positive and negative affect toward the patient, but not by attributions of responsibility for drug use. Deservingness judgments emerged as strong predictors of nurses' satisfaction with the provision of high- or low-quality care. The findings imply that the deservingness judgments made by nurses reflected strong entitlement norms concerning the provision of proper care for patients that were independent of patients' perceived responsibility for their condition.