Statistical properties of the rWG(J) index of agreement

L. R. James, R. G. Demaree, and G. Wolf (1984) introduced rWG(J) to estimate interrater agreement for a group. This index is calculated by comparing an observed group variance with an expected random variance. As researchers have gained experience using this index, several questions have arisen. What are the consequences of replacing values beyond the unit interval by 0? What is the dependence of rWG(J) on the group size? The authors' simulations show that a positive bias is caused by the truncation, but for large population values of rWG(J) it is negligible. Also, in this case, the group size has no effect on the expected value of rWG(J). For inference on rWG(J), researchers can exploit the availability of computers to simulate data from the hypothesized distribution and then compare the simulation results for rWG(J) with the actual values. In addition, it is shown how the bootstrap method can be used for comparing the indices of 2 groups.     

Target detection in scientific visualization

Three experiments were conducted to test participants' ability to detect targets in colored spatial displays using 7-level bipolar scales. Experiment 1 assessed the ability of participants to detect high or low targets using 12 scales whose poles either were directly opposed in color space or had a primary and an intermediate hue at each pole. Experiment 2 used 8 scales whose arms were orthogonal in color space. Experiment 3 examined the simultaneous detection of high and low targets. Although there are notable exceptions, scales that are close to or above the horizontal (red-green) axis in color space perform best. Of the scales with orthogonal arms, those that are oriented downward, toward the blues, in color space are least satisfactory. Scales that are asymmetrically effective are common, and applications requiring good detectability at both extremes must take this into account. The results are discussed in the context of the evolution of trichromatic color vision.     

Cross-cultural aspects of fears in African children and adolescents

The purpose of this study was to compare level and type of fears in Nigerian and Kenyan children using the Fear Survey Schedule for Children, Revised (FSSC-R; [Ollendick, T.H. (1983). Reliability and validity of the Revised Fear Survey Schedule for Children (FSSC-R). Behaviour Research and Therapy, 21, 685-692]). A total of 852 males and females between the ages of 8 and 17 were surveyed. Results indicated that Nigerian children reported significantly higher total fear than Kenyan children and that scores from both countries were higher than those found in the United States, Australia and China. This suggests that the cultures of Kenya and Nigeria may share a common variable that makes reporting of fears greater than that reported by children of other world cultures. In addition, Christian children in both countries reported higher levels of fear on several factors than Muslim children, indicating that Islamic beliefs may encourage children to report less fear or to deal with their fears better than Christian beliefs. Finally, children between the ages of 8 and 12 reported greater fear of the unknown than children between 13 and 17 years of age. Overall, these findings suggest that important cultural, religious and age differences exist for levels of childhood fears reported in Nigeria and Kenya.     

Compression of visual space in natural scenes and in their photographic counterparts

Classical theories of space perception posit continuous distortions of subjective space. These stand in contrast to the quantitatively and qualitatively different distortions experienced in space that is represented pictorially. We challenge several aspects of these theories. Comparing real-world objects with depictions of the same objects, we investigated to what extent distortions are introduced by the photographic medium. Corners of irregularly shaped buildings had to be judged in terms of the vertical dihedral angles subtended by two adjacent walls. Across all conditions, a robust effect of viewing distance was found: Building corners appear to flatten out with distance. Moreover, depictions of corners produce remarkably similar results and should not receive a different theoretical treatment than do real-world scenes. The flattening of vertical angles cannot be explained by a linear distortion of the entire visual space. We suggest that, for natural scenes, compression of space is local and dependent on contextual information.     

Staying alive: evolution, culture, and women's intrasexual aggression

Females' tendency to place a high value on protecting their own lives enhanced their reproductive success in the environment of evolutionary adaptation because infant survival depended more upon maternal than on paternal care and defence. The evolved mechanism by which the costs of aggression (and other forms of risk taking) are weighted more heavily for females may be a lower threshold for fear in situations which pose a direct threat of bodily injury. Females' concern with personal survival also has implications for sex differences in dominance hierarchies because the risks associated with hierarchy formation in nonbonded exogamous females are not offset by increased reproductive success. Hence among females, disputes do not carry implications for status with them as they do among males, but are chiefly connected with the acquisition and defence of scarce resources. Consequently, female competition is more likely to take the form of indirect aggression or low-level direct combat than among males. Under patriarchy, men have held the power to propagate images and attributions which are favourable to the continuance of their control. Women's aggression has been viewed as a gender-incongruent aberration or dismissed as evidence of irrationality. These cultural interpretations have "enhanced" evolutionarily based sex differences by a process of imposition which stigmatises the expression of aggression by females and causes women to offer exculpatory (rather than justificatory) accounts of their own aggression.     

Age differences in personality across the adult life span: parallels in five cultures

Both cross-sectional and longitudinal studies in the United States have shown consistent changes between college age and middle adulthood. There appear to be declines in 3 of the 5 major factors of personality--Neuroticism, Extraversion, and Openness--and increases in Agreeableness and Conscientiousness. To examine cross-cultural generalizability of these findings, translations of the Revised NEO Personality Inventory were administered to samples in Germany, Italy, Portugal, Croatia, and South Korea (N = 7,363). Similar patterns of age differences were seen in each country, for both men and women. Common trends were also seen for the more specific traits that define the major factors. Because these nations differ substantially in culture and recent history, results suggest the hypothesis that these are universal maturational changes in adult personality.     

Early developments in the ability to understand the relation between stimulus and reward

Delayed nonmatching to sample (DNMS) is used to test the recognition memory function dependent on the medial temporal lobe. Children cannot succeed on this task until about 21 months. Because robust recognition is present well before then, the late emergence of another ability must account for the late success on DNMS. Evidence is presented here that the critical late-maturing competence is the ability to grasp the relation between stimulus and reward--that is, to understand that the stimulus is a symbol or marker for the reward. Infants of 9 and 12 months were tested on 3 conditions of DNMS. A sample object was presented. After a delay, the sample and a novel object appeared; choice of the novel object was rewarded. In the standard task, the reward was in a well beneath the stimulus. In the verbal-reward condition the reward was not a separate object but was praise and applause. In the Velcro condition, the reward, although a separate and separable object, was attached to the base of the stimulus. Most infants at both ages succeeded in the verbal-reward and Velcro conditions but not in the standard condition.     

Maternal care and attachment security in ordinary and emergency contexts

One of the foundations of attachment theory is the notion that early care plays a key role in determining the quality of child-caregiver attachment relationships. Studies have consistently shown relations between maternal sensitivity and infant security. Further research is required to resolve issues arising from modest correlations, focus on research in stressful as opposed to ordinary contexts, and questions about the generality of results across cultures and social contexts and about the context specificity of caregiving behavior. This article addressed these issues in 2 studies of child care in home and hospital contexts. Q-sort scores derived from extended naturalistic observations were used. Results are discussed in terms of links between methodology and effect sizes, the generality of links between maternal care and child security, the need for further research on caregiving in ordinary and emergency situations, and the context sensitivity of maternal behavior.     

Development and initial validation of a brief mental health outcome measure

Using a combination of classical test theory and Rasch item analysis, we developed a short scale designed to measure the effectiveness of mental health treatment across a wide range of mental health services and populations. Item development for the scale was guided by literature review and interviews with senior clinicians and with patients. Using 3 different samples consisting of inpatients, outpatients, and nonpatients, we reduced our initial item pool from 81 to 10 items. The 10-item scale had an alpha of .96 and showed strong correlations with commonly used measures of psychological well-being and distress. Our results suggest that the scale appears to measure a broad domain of psychological health. The scale appeared to lack ceiling and floor effects, and it discriminated between inpatients, outpatients, and nonpatients, suggesting the scale has excellent potential to be broadly responsive to a variety of treatment effects. In addition, the new scale proved to be sensitive to treatment changes in a sample of 20 psychiatric inpatients. Overall, the initial data suggest that we have developed a brief, sensitive outcome measure designed to have wide application across psychiatric and psychological treatments and populations.     

Cultural background and coping with loneliness

The present study is an examination of the influence of cultural background on an individual's ability to cope with loneliness. Participants were from 3 cultural backgrounds: North American, South Asian, and West Indian. A total of 679 participants (318 men and 361 women) answered an 18-item loneliness questionnaire. Results revealed significant differences in the coping strategies that the participants used. Gender differences were also found across the cultures and within each culture.