Costs and benefits in perceptual categorization

Observers categorized perceptual stimuli when the category costs and benefits were manipulated across conditions, and costs were either zero or nonzero. The cost-benefit structures were selected so that performance across conditions was equivalent with respect to the optimal classifier. Each observer completed several blocks of trials in each of the experimental conditions, and a series of nested models was applied to the individual observer data from all conditions. In general, performance became more nearly optimal as observers gained experience with the cost-benefit structures, but performance reached asymptote at a suboptimal level. Observers behaved differently in the zero- and nonzero-cost conditions, performing consistently worse when costs were nonzero. A test of the hypothesis that observers weight costs more heavily than benefits was inconclusive. Some aspects of the data supported this differential weighting hypothesis, but others did not. Implications for current theories of cost-benefit learning are discussed.     

Stories of Relative Privilege: Power and Social Change in Feminist Community Psychology

Stories about community work in New Zealand and Scotland are presented to describe and reflect on issues central to feminist community psychology. Organizing a lesbian festival, Ingrid Huygens describes feminist processes used to equalize resources across Maori (indigenous) and Pakeha (white) groups. Heather Hamerton presents her experiences as a researcher using collective memory work to reflect on adolescent experiences related to gender, ethnicity, and class. Sharon Cahill chronicles dilemmas and insights from focus groups about anger with women living in public housing in Scotland. Each story chronicles experiences related to oppression and privilege, and describes the author's emotions and reflections. Individually and collectively, the stories illustrate the potential offered by narrative methods and participatory processes for challenging inequalities and encouraging social justice.     

The reliability and validity of the Perceived Stigmatization Questionnaire (PSQ) and the Social Comfort Questionnaire (SCQ) among an adult burn survivor sample

In this study, 361 adult burn survivors completed the Perceived Stigmatization Questionnaire (PSQ), the Social Comfort Questionnaire (SCQ), and other measures. Both the PSQ and SCQ had good internal consistency indices. Factor analysis of the PSQ yielded 3 factors (absence of friendly behavior, confused/staring behavior, and hostile behavior). The SCQ had 1 factor. Conjoint factor analysis with measures of related constructs (body esteem, body-esteem importance, depression, social support) suggested that PSQ and SCQ measure distinct constructs. Correlations with the related psychosocial constructs and burn characteristics suggested the PSQ and SCQ have good convergent and discriminant validity. Limitations of the study are discussed.     

Perinatal maternal undernutrition programs the offspring hypothalamo-pituitary-adrenal (HPA) axis

There is now compelling evidence, coming both from animal and human studies that an early exposure to undernutrition is frequently associated with low birth weight and programs HPA axis alterations throughout the lifespan. Although animal models have reported conflicting findings arising from differences in experimental paradigms and species, they have clearly demonstrated that such programming not only affects the brain but also the pituitary corticotrophs and the adrenal cortex. In fetuses, maternal undernutrition reduces HPA axis function and implicates a reduction of placental 11beta-HSD2 activity and a greater transplacental transfer of glucocorticoids (GRs). In young adults, usually only fine HPA axis alterations were observed, whereas in older ones, maternal undernutrition was frequently associated with chronic hyperactivity of this neuroendocrine axis. In humans, evidence of HPA axis dysregulation in people who were small at birth has recently emerged. Thus, we suggest that such alterations in adults may be implicated in the aetiology of several disorders related to the metabolic syndrome as well as to immune or inflammatory diseases. To reverse such programming, recent experimental reports have shown that postnatal environmental interventions, dietary modifications and the use of agents modulating the epigenomic state could partly restore physiological functions and thus open new therapeutic strategies.     

A quantitative model-based approach to examining aging effects on information-integration category learning

Information-integration category learning was examined in older and younger adults. Accuracy results indicated that older participants learned less well than younger participants in both linear and nonlinear conditions. Model-based analyses indicated that both groups in the linear condition tended to use information integration but that later in training younger participants were more likely to do so. In contrast, the 2 groups in the nonlinear condition were equally likely to use information integration. Further analysis indicated that younger adults were more accurate than older adults when an information-integration approach was adopted, whereas fewer age-related differences were observed when a rule-based approach was used, suggesting that age can have a negative impact on information-integration category learning processes but less impact on rule-based learning.     

A test of the optimal classifier's independence assumption in perceptual categorization

Observers completed perceptual categorization tasks that included separate base-rate/payoff manipulations, corresponding simultaneous base-rate/payoff manipulations, and conflicting simultaneous base-rate/payoff manipulations. Performance (1) was closer to optimal for 2:1 than for 3:1 base-rate/payoff ratios and when base rates as opposed to payoffs were manipulated, and (2) was more in line with the predictions from the flat-maxima hypothesis than from the independence assumption of the optimal classifier in corresponding and conflicting simultaneous base-rate/payoff conditions. A hybrid model that instantiated simultaneously the flat-maxima and the competition between reward and accuracy maximization (COBRA) hypotheses was applied to the data. The hybrid model was superior to a model that incorporated the independence assumption, suggesting that violations of the independence assumption are to be expected and are well captured by the flat-maxima hypothesis without requiring any additional assumptions. The parameters indicated that observers' reward-maximizing decision criterion rapidly approaches the optimal value and that more weight is placed on accuracy maximization in separate and corresponding simultaneous base-rate/payoff conditions than in conflicting simultaneous base-rate/payoff conditions.     

MULTICOMPONENT INTERVENTION FOR AGITATED BEHAVIOR IN A PERSON WITH ALZHEIMER'S DISEASE

We evaluated a multicomponent intervention for agitated behavior in a man with probable Alzheimer's disease. Hypotheses about variables controlling his agitated behavior guided intervention design. Based on staff interviews, direct observations, and brief experimental probes, intervention components were chosen to increase rate of reinforcement and decrease aversive aspects of his job. Intervention reduced agitated behavior without disrupting his work rate.