Temporal context and conditioned reinforcement value

The effectiveness of a stimulus as a conditioned reinforcer depends on the temporal context of reinforcement, that is, the overall rate of reinforcement in the situation. The dominant view has been that context determines the learned value of a stimulus directly, according to delay-reduction theory. By contrast, the contextual choice model (CCM) maintains that value is independent of context and incorporates the effects of context on choice in the framework of the matching law. The authors report 2 experiments with pigeons as subjects that use transfer tests to assess the value of stimuli in the concurrent-chains procedure. Results strongly support the assumption of CCM that pigeons learn the temporal relations between events independently of context but that context modulates the expression of that learning as choice.     

Optimistic bias among potential perpetrators and victims of youth violence

This study furthers the current understanding of optimistic bias regarding youth violence among high school students. Results from a survey of 387 urban high school students indicate a wide range of predictors of optimistic bias, including experience, demographics, and attitudes. Linkages to other developmental frameworks (personal fable and self-efficacy) suggest future directions for additional research.     

Extending neuropsychological assessments into the primary mental ability space

A battery of 17 neuropsychological tests (including the CERAD battery) and 17 psychometric ability tests were administered to a sample of 499 participants of the Seattle Longitudinal study who had been given the psychometric ability tests seven and 14 years earlier. The neuropsychological tests were projected into a 5-factor psychometric ability space by means of extension analysis. The concurrent regressions of the neuropsychology tests on the psychometric ability tests were then used to estimate neuropsychology test scores from the psychometric ability tests administered in 1984, 1991 and 1998. Neuropsychologists then rated the study participants as either normal, suspect or cognitively impaired in 1998. Changes in estimated test scores were computed over seven and fourteen years. Significant odds ratios between normal and cognitively impaired groups were found for all neuropsychological tests over the proximal period and for most tests over the 14-year period. Similar findings occurred for the odds ratios between the normal and suspect groups for the most proximal 7-year changes.     

The Seattle longitudinal study: relationship between personality and cognition

This article reviews the history, measures and principal findings of the Seattle Longitudinal Study. This study began in 1956 focusing upon age differences and age changes in cognitive abilities. Its sampling frame is a large HMO in the Pacific Northwest. The study has been expanded to investigate various influences on cognitive aging including, cognitive styles, personality traits, life styles, and family environment. Current interest is also in the early detection of risk for dementia. In addition, this article reports original analyses of the relation of personality dimensions to cognitive abilities (both concurrent and longitudinal). While personality remains relatively stable over the adult life span, modest proportions of variance are shared between various personality traits and the cognitive abilities.     

Silent thoughts,spoken wishes: when candidate experience of the supervisor converges with patient fantasies

How and why a candidate's private experience of two supervisors emerged in patients' fantasies about them is explored. Four issues are examined in light of two control cases: (1) Patients divide, rather than split, the transference between supervisor and candidate, experiencing both ambivalently. (2) Even a patient with no knowledge of the supervisor's identity may have a fantasy of the supervisor that is congruent with the candidate's experience of the supervisor. (3) When new professional traits emerge in the candidate as he or she identifies with his or her mentor, the patient may attribute them to the invisible person in the room--the supervisor; the patient may intuit and be influenced by the candidate's feelings about the supervisor as well. (4) A patient's fantasies about the supervisor may reflect parallel process in reverse, whereby the patient discerns what is going on between supervisor and candidate through his or her treatment, just as the supervisor reads what is going on between patient and candidate through the candidate's reporting of the treatment. Because the trio is the truth of the training case, it seems fitting and empowering to acknowledge and analyze the role of the supervisor in the patient's mind.     

Two Approaches for Identifying Shared Personality Dimensions Across Methods

Two approaches are illustrated, one exploratory and one confirmatory, or determining the extent to which personality dimensions are invariant across different methods of measurement. Using the interbattery factor model (Browne, 1979, 1980; Tucker, 1958), Study 1 explores the links between the Five-Factor Model of Personality, as assessed by the NEO-PI (Costa & McCrae, 1985), and the Needs system of Murray, as assessed by the Personality Research Form (Jackson, 1984). Study 2 uses an interbattery approach to examine the common structure underlying two widely used coping measures: the revised Ways of Coping Cchecklis (Folkman, Lazarus, Dunkel-Schetter, Delongis, & Gruen, 1986) and the COPE Inventory (Carver, Scheier, & Weintraub, 1989). The two studies illustrate the use of interbattery factor analysis as a means of separating battery-specific (method) factors from interbattery (trait) factors, in contrast to traditional factor analysis that describes underlying structure without regard to method of measurement. By maintaining the distinction between variability that is method-specific and variability that is common across methods, the interbattery factor model allows the common trait structure underlying multiple measures to be described more accurately.     

Ethnicity and Social Support During Pregnancy

Data from two multi-ethnic prospective studies of African American, Latina, and non-Hispanic White pregnant women were used to examine the influence of contextual factors on social support processes during pregnancy. Multiple types of support (perceived support, received support, support satisfaction, network support) and sources of support (baby's father, family, friends) were assessed. The role of ethnicity in social support was examined after controlling for the contribution of related contextual factors (SES, marital status, age, parity, employment) to these processes. The impact of ethnicity and related contextual factors differed across sources of social support. Ethnic differences in support from family and friends, but not from the baby's father, emerged. However, marital status was a consistent predictor of support from the baby's father, and SES was a consistent predictor of support from friends. Overall, the findings of two studies suggest that although ethnicity is associated with support from friends and family, other contextual factors, such as marital status and SES, influence support processes during pregnancy.     

Adult mice maintained on a high-fat diet exhibit object location memory deficits and reduced hippocampal SIRT1 gene expression

Mounting evidence has established that diet-induced obesity (DIO) is associated with deficits in hippocampus-dependent memory. The bulk of research studies dealing with this topic have utilized rats fed a high-fat diet as an experimental model. To date, there has been a paucity of research studies that have established whether the memory deficits exhibited in DIO rats can be recapitulated in mice. Moreover, the majority of experiments that have evaluated memory performance in rodent models of DIO have utilized memory tests that are essentially aversive in nature (i.e., Morris water maze). The current study sought to fill an empirical void by determining if mice maintained on a high-fat diet exhibit deficits in two non-aversive memory paradigms: novel object recognition (NOR) and object location memory (OLM). Here we report that mice fed a high-fat diet over 23 weeks exhibit intact NOR, albeit a marked impairment in hippocampus-dependent OLM. We also determined the existence of corresponding aberrations in gene expression within the hippocampus of DIO mice. DIO mice exhibited significant reductions in both SIRT1 and PP1 mRNA within the hippocampus. Our data suggest that mice maintained on a high-fat diet present with impaired hippocampus-dependent spatial memory and a corresponding alteration in the expression of genes that have been implicated in memory consolidation.