Biomedical subjects

Keith F Widaman

Publications and source records attributed to Keith F Widaman.

11 recordsLinked to original sources

PubMed2005

Confirmatory factor analysis of personality structure in adult male rhesus monkeys (Macaca mulatta).

Reports from different laboratories have suggested that nonhuman primates have somewhat similar dimensions of personality. To date, however, no attempts have been made to statistically replicate a specific factor structure. In the present report, two independent observers recorded the behavior of 58 adult male rhesus monkeys, and then rated the animals with the use of a 50-item personality instrument. A confirmatory factor analysis (CFA) of the ratings resulted in the replication of a previously described four-factor personality structure [Maninger et al., American Journal of Primatology 61:73-83, 2003]. The first two dimensions-Sociability and Confidence-showed strong loadings and are similar to Affiliation and Agency dimensions in humans. The remaining dimensions-Equability and Irritability-were less clear, and it is possible that additional traits will have to be identified before a more robust structure can be established for these dimensions.

Animals↗

PubMed2005

Reciprocal links among differential parenting, perceived partiality, and self-worth: a three-wave longitudinal study.

This study examined reciprocal links between parental differential treatment, siblings' perception of partiality, and self-worth with 3 waves of data from 384 adolescent sibling dyads. Results suggest that birth-order status was significantly associated with self-worth and perception of maternal and paternal differential treatment. There was a consistent across-time effect of self-worth on perception of parental partiality for later born siblings, but not earlier born siblings, and a consistent effect of differential treatment on perception of partiality for earlier born but not later born siblings. The results contribute new insight into the associations between perception of differential parenting and adolescents' adjustment and the role of birth order.

Adolescent↗

PubMed2004

Recall and recognition in mild hypoxia: using covariance structural modeling to test competing theories of explicit memory.

To test theories of explicit memory in amnesia, we examined the effect of hypoxia on memory performance in a group of 56 survivors of sudden cardiac arrest. Structural equation modeling revealed that a single-factor explanation of recall and recognition was insufficient to account for performance, thus contradicting single-process models of explicit memory. A dual-process model of recall in which two processes (e.g., declarative memory and controlled search) contribute to recall performance, whereas only one process (e.g., declarative memory) underlies recognition performance, also failed to explain the results adequately. In contrast, a dual-process model of recognition provided an acceptable account of the data. In this model, two processes--recollection and familiarity--underlie recognition memory, whereas only the recollection process contributes to free recall. The best-fitting model was one in which hypoxia and aging led to deficits in recollection, but left familiarity unaffected. Moreover, a controlled search process was correlated with recollection, but was not associated with familiarity or the severity of hypoxia. The results support models of explicit memory in which recollection depends on the hippocampus and frontal lobes, whereas familiarity-based recognition relies on other brain regions.

Aged↗

PubMed2003

Stigma, social risk, and health policy: public attitudes toward HIV surveillance policies and the social construction of illness.

Data from a 1999 national telephone survey with a probability sample of English-speaking US adults (N=1,335) were used to assess how support for HIV surveillance policies is related to AIDS stigma and negative attitudes toward groups disproportionately affected by the epidemic. Anonymous reporting of HIV results to the government was supported by a margin of approximately 2-to-l, but name-based reporting was opposed 3-to-l. Compared with other respondents, supporters of name-based surveillance expressed significantly more negative feelings toward people with AIDS, gay men, lesbians, and injecting drug users. More than one third of all respondents reported that concerns about AIDS stigma would affect their own decision to be tested for HIV in the future. Implications for understanding the social construction of illness and for implementing effective HIV surveillance programs are discussed.

AIDS Serodiagnosis↗

PubMed2003

On specifying the null model for incremental fit indices in structural equation modeling.

In structural equation modeling, incremental fit indices are based on the comparison of the fit of a substantive model to that of a null model. The standard null model yields unconstrained estimates of the variance (and mean, if included) of each manifest variable. For many models, however, the standard null model is an improper comparison model. In these cases, incremental fit index values reported automatically by structural modeling software have no interpretation and should be disregarded. The authors explain how to formulate an acceptable, modified null model, predict changes in fit index values accompanying its use, provide examples illustrating effects on fit index values when using such a model, and discuss implications for theory and practice of structural equation modeling.

Data Interpretation, Statistical↗

PubMed2003

The difference engine: a model of diversity in speeded cognition.

A theory of diversity in speeded cognition, the difference engine, is proposed, in which information processing is represented as a series of generic computational steps. Some individuals tend to perform all of these computations relatively quickly and other individuals tend to perform them all relatively slowly, reflecting the existence of a general cognitive speed factor, but the time required for response selection and execution is assumed to be independent of cognitive speed. The difference engine correctly predicts the positively accelerated form of the relation between diversity of performance, as measured by the standard deviation for the group, and task difficulty, as indexed by the mean response time (RT) for the group. In addition, the difference engine correctly predicts approximately linear relations between the RTs of any individual and average performance for the group, with the regression lines for fast individuals having slopes less than 1.0 (and positive intercepts) and the regression lines for slow individuals having slopes greater than 1.0 (and negative intercepts). Similar predictions are made for comparisons of slow, average, and fast subgroups, regardless of whether those subgroups are formed on the basis of differences in ability, age, or health status. These predictions are consistent with evidence from studies of healthy young and older adults as well as from studies of depressed and age-matched control groups.

Cognition↗

PubMed2003

Relation of prenatal phenylalanine exposure to infant and childhood cognitive outcomes: results from the International Maternal PKU Collaborative Study.

OBJECTIVE: The primary aims of this study were to model the form of the relation between prenatal exposure to phenylalanine (Phe) and measures of offspring intellectual development and to estimate the developmental relations of maternal demographic, pregnancy-related, and perinatal variables on offspring intelligence during infancy and childhood. METHODS: The participants were the 413 children and their mothers from the International Maternal PKU Collaborative Study. RESULTS: Results supported a nonlinear relation between prenatal Phe exposure and offspring cognitive outcomes, with damage to the developing fetus if average Phe levels are above approximately 360 micromol/L. Moreover, prenatal Phe exposure had a strong effect on offspring outcomes at 1 year of age and was the only one of the background, pregnancy-related, or perinatal variables to influence directly offspring outcomes at 2, 4, and 7 years of age. CONCLUSION: The present study was able to document the importance of prenatal exposure to Phe for predicting offspring cognitive outcomes in the presence of other predictors of these outcomes.

Aptitude Tests↗

PubMed2002

Effects of extensive temporal lobe damage or mild hypoxia on recollection and familiarity.

Memory for past events can be based on recollection or on assessments of familiarity. These two forms of human memory have been studied extensively by philosophers and psychologists, but their neuroanatomical substrates are largely unknown. Here we examined the brain regions that are involved in these two forms of memory by studying patients with damage to different temporal lobe regions. Our results come from (i) structural covariance modeling of recall and recognition, (ii) introspective reports during recognition and (iii) analysis of receiver operating characteristics. In sum, we found that the regions disrupted in mild hypoxia, such as the hippocampus, are centrally involved in conscious recollection, whereas the surrounding temporal lobe supports familiarity-based memory discrimination.

Cerebral Infarction↗

PubMed2002

HIV-related stigma and knowledge in the United States: prevalence and trends, 1991-1999.

OBJECTIVES: This study assessed the prevalence of AIDS stigma and misinformation about HIV transmission in 1997 and 1999 and examined trends in stigma in the United States during the 1990s. METHODS: Telephone surveys with national probability samples of English-speaking adults were conducted in the period 1996 to 1997 (n = 1309) and in 1998 to 1999 (n = 669). Findings were compared with results from a similar 1991 survey. RESULTS: Overt expressions of stigma declined throughout the 1990s, with support for its most extreme and coercive forms (e.g., quarantine) at very low levels by 1999. However, inaccurate beliefs about the risks posed by casual social contact increased, as did the belief that people with AIDS (PWAs) deserve their illness. In 1999, approximately one third of respondents expressed discomfort and negative feelings toward PWAs. CONCLUSION: Although support for extremely punitive policies toward PWAs has declined, AIDS remains a stigmatized condition in the United States. The persistence of discomfort with PWAs, blame directed at PWAs for their condition, and misapprehensions about casual social contact are cause for continuing concern and should be addressed in HIV prevention and education programs.

Acquired Immunodeficiency Syndrome↗

PubMed1993

Confirmatory factor analysis and item response theory: two approaches for exploring measurement invariance.

This study investigated the utility of confirmatory factor analysis (CFA) and item response theory (IRT) models for testing the comparability of psychological measurements. Both procedures were used to investigate whether mood ratings collected in Minnesota and China were comparable. Several issues were addressed. The first issue was that of establishing a common measurement scale across groups, which involves full or partial measurement invariance of trait indicators. It is shown that using CFA or IRT models, test items that function differentially as trait indicators across groups need not interfere with comparing examinees on the same trait dimension. Second, the issue of model fit was addressed. It is proposed that person-fit statistics be used to judge the practical fit of IRT models. Finally, topics for future research are suggested.

Adult↗

PubMedDate not supplied

Economic stress, parenting, and child adjustment in Mexican American and European American families.

To assess the impact of economic hardship on 111 European American and 167 Mexican American families and their 5th-grade (M age=11.4 years) children, a family stress model was evaluated. Structural equation analyses revealed that economic hardship was linked to indexes of economic pressure that were related to depressive symptoms for mothers and fathers of both ethnicities. Depressive symptoms were linked to marital problems and hostile parenting. Paternal hostile parenting was related to child adjustment problems for European Americans, whereas marital problems were linked to child adjustment problems for Mexican Americans. Maternal acculturation was associated with both higher marital problems and lower hostile parenting. The utility of the model for describing the effects of economic hardship in Mexican Americans is noted.

Adaptation, Psychological↗