What guides a search for food that has disappeared? Experiments on cotton-top tamarins (Saguinus oedipus).

When food is launched down a vertically positioned S-shaped opaque tube, cotton-top tamarins (Saguinus oedipus) search for the food in the position directly beneath the release point, even though over several trials it never appears in this position (B. M. Hood et al., 1999). Experiment 1 showed that when the trajectory of the food shifts from the vertical to the horizontal plane, tamarins no longer show systematic perseverative errors and, in general, perform better on this invisible displacement task. Experiment 2 showed that tamarins with experience on the horizontal task show less of a bias when tested on the vertical task but nonetheless fail overall to solve this invisible displacement problem; their performance is substantially worse than it was on the horizontal task. Experiment 3 revealed that when the vertically positioned tube is replaced by an occluded ramp, tamarins consistently search in the compartment below the release point, even though most of the tamarins had experience in Experiments 1 and 2. Overall, results indicate that tamarins have a significant gravity bias when searching for food that has disappeared along the vertical plane but also have more general problems finding food that has moved out of sight.     

Genetic Influence Helps Explain Variation in Human Fertility: Evidence From Recent Behavioral and Molecular Genetic Studies

To search for genetic influence on human fertility differentials appears inconsistent with past empirical research and prior interpretations of Fisher's fundamental theorem of natural selection. We discuss Fisher's theorem and give reasons why genetic influences may indeed account for individual differences in human fertility. We review recent empirical studies showing genetic influence on variance in fertility outcomes and precursors to fertility. Further, some of the genetic variance underlying fertility outcomes overlaps with that underlying fertility precursors. Findings from different cultures, different times, different levels of data, and both behavioral and molecular genetic designs lead to the same conclusion: Fertility differentials are genetically influenced, and at least part of the influence derives from behavioral precursors that are under volitional control, which are themselves genetically mediated.     

Kids and Teens in Court (KTIC): A Model for Preparing Child Witnesses for Court

Each year, numerous children testify in the United States in either criminal, civil, or juvenile court cases. Typically, children who testify are alleged victims of sexual or physical abuse or neglect, witnesses to violent crime, or subjects in custodial hearings in civil court. As more maltreatment cases are prosecuted and child custody is contested, an increasing number of children are being called as witnesses in court. Many of these children have already been traumatized by the experiences that led to their need to testify, and participation in the court process can have additional negative effects. This article describes the development and recent formative evaluation of a court preparation program that provides psychoeducation and utilizes components of evidence-based trauma treatment approaches, such as relaxation and in vivo exposure, to support child witnesses and reduce the risk of retraumatization. Children and adolescents participating in the program attend group sessions conducted by mental health clinicians and complete a court-related anxiety measure before and after each session. Results from 175 participants are reported. Findings indicated significant decreases in court-related anxiety with large program effects. Challenges encountered by the program and future directions are discussed.     

Facilitating autonomous motivation for smoking cessation.

Physicians used either an autonomy-supportive or a controlling interpersonal style to counsel smokers based on National Cancer Institute guidelines. Physician autonomy support was rated from audiotapes, and patients' perceived competence and autonomous motivation for quitting were self-reported on questionnaires. Validated point prevalences for 6, 12, and 30 months and for continuous cessation were examined. The intervention did not have a direct effect on quit rates; however, structural equation modeling supported the self-determination process model of smoking cessation. The model indicated that the autonomy-supportive intervention was rated as more autonomy supportive, that rated autonomy support predicted autonomous motivation, and that autonomous motivation predicted cessation at all points in time. Perceived competence contributed independent variance to cessation only at 6 months.     

Social-cognitive determinants of physical activity: the influence of social support, self-efficacy, outcome expectations, and self-regulation among participants in a church-based health promotion study.

A social-cognitive model of physical activity was tested, using structural equation analysis of data from 999 adults (21% African American; 66% female; 38% inactive) recruited from 14 southwestern Virginia churches participating in the baseline phase of a health promotion study. Within the model, age, race, social support, self-efficacy, and self-regulation contributed to participants' physical activity levels, but outcome expectations did not. Of the social-cognitive variables, self-regulation exerted the strongest effect on physical activity. Independent of self-regulation, self-efficacy had little effect. Social support influenced physical activity as a direct precursor to self-efficacy and self-regulation. The model provided a good fit to the data and explained 46% of the variance in physical activity among the diverse group of adults.     

A defence of the lexical approach to the study of personality structure

In recent years there have been many investigations of personality structure, and much of this research has been based on the lexical strategy for finding the major personality dimensions. However, this approach has frequently been criticized on several grounds, including concerns regarding the use of adjectives as personality variables, the use of lay observers of personality, the limited explanatory power of lexically derived personality dimensions, and the lack of any similar strategies used in other sciences. In this paper, these criticisms are addressed in detail and judged to be invalid. It is argued that the study of personality structure via the lexical approach is an important area of research. Copyright © 2004 John Wiley & Sons, Ltd.