Spearman's law of diminishing returns: A statistical artifact?

Spearman's Law of Diminishing Returns (SLODR) is the idea that the structure of human cognitive ability is more differentiated and g a weaker determinant of cognitive performance at higher levels of ability. In this study, we distinguish between ‘traditional’ methods of testing SLODR and ‘contemporary’ methods of testing SLODR. It is the former set of methods from which the vast majority of the evidence base for SLODR derives. We demonstrated that it is easy to mimic SLODR and reverse SLODR effects in these traditional methods of assessing SLODR by using data with skewed observed variable distributions. The skewness magnitudes did not need to be large to produce these effects and they fell well within the range of values that are usually considered unproblematic for parametric statistic analysis. In simulated datasets, positive subtest skewness resulted in SLODR and negative subtest skewness resulted in reverse SLODR. In contemporary methods of testing SLODR, non-linear g-loadings or a skewed g are assumed to reflect evidence for SLODR. When we applied contemporary methods of testing SLODR to these data, there was evidence of heteroscedastic residuals but no evidence of non-linear g-loadings or skewed g distributions. We broadly replicated the effects of subtest skew from these simulated datasets in real data from the Minnesota Study of Twins Reared Apart. Results imply that traditional methods of assessing SLODR cannot distinguish between effects due to subtest characteristics that have nothing to do with differences in ability structure at different levels of g and true SLODR effects. This calls into question the empirical support for SLODR.     

Psychometric evaluation of the eating disorder inventory (edi) in a clinical group

Abstract

This study examined the psychometric properties of the Eating Disorder Inventory (EDI) with a clinical sample of 79 female clients seen at an outpatient eating disorder program. The means and standard deviations for the bulimia nervosa subgroup in this study (n = 48) compared favorably with the bulimia group in the EDI Manual Supplement (1986) on all eight subscales, except Drive for Thinness. The present non-student sample had significantly lower scores on this particular subscale than did the norm group (mostly students). Another difference was that the local bulimic subgroup had significantly higher present and minimum weights (as a percentage of the expected average weight according to height). The EDI subscales also displayed respectable internal consistency reliability with this sample. In contrast to previous research, however, only five factors were found in a factor analysis rather than eight corresponding to the original subscales for the EDI. Differences between bulimic and a not-otherwise-specified (NOS) diagnostic groups were also found on both the EDI Ineffectiveness and Bulimia subscales (NOS had lower scores). The results of this study are discussed in terms of the importance of undertaking local standardization of tests in clinical settings.     

An evaluation of the accuracy of self-reports for predicting menstrual onset

Abstract

The self-reported predicted and actual day of menstrual onset were compared for 107 female volunteers. The differences between predicted and actual day of menstrual onset were compared by categorizing women into the ovulatory, premenstrual, and menstrual phases separately based on their predicted and actual days of menstrual onset. A main effect for phase suggested that menstrual women were less accurate in predicting menstrual onset. Thus, the degree of inaccuracy differed by phase and varied as a function of whether predicted or actual menstrual onset date was used to assign women to phases. These data provide a more precise indication of the degree of unreliability of self-reports and suggest a phase-accuracy connection which may be influenced by a number of factors, particularly recall of last menstrual onset.     

Individual and collaborative implementation intentions and the promotion of breast self-examination

Implementation intentions, plans relating to when and where behaviours will be performed, have been effective in increasing health behaviour. Two studies are reported that test the impact of this strategy in promoting breast self-examination (BSE), a behaviour shown to aid the early detection of tumours. In study 1, 457 participants were randomly allocated to either implementation intention or control conditions. Implementation intentions significantly increased the likelihood of BSE at one month. The effect of the intervention was marginally significant at six months. Study 2 (N?=?101) tested the efficacy of a collaborative implementation intention intervention that required female participants to plan, with a partner, collaborative BSE performance. Results indicated that both implementation intentions and partner involvement were associated with BSE performance at one month, whilst the collaborative implementation intention intervention showed a 100% success rate. Collaborative implementation intentions may reduce forgetfulness. Interventions that encourage partner involvement in planning and enacting behaviour appear to enhance implementation intention utility.     

Effect of pretesting on intentions and behaviour: A pedometer and walking intervention

This study addressed the influence of pedometers and a pretest on walking intentions and behaviour. Using a Solomon four-group design, 63 female university students were randomly assigned to one of four conditions: pedometer and pretest (n = 16), pedometer and no pretest (n = 16), no pedometer and pretest (n = 15), no pedometer and no pretest (n = 16). The pretest conditions included questions on walking, intentions to walk 12,500 steps per day, and self-efficacy for walking 12,500 steps per day. In the pedometer conditions a Yamax Digi-Walker SW-650 pedometer was worn for one week. All participants completed posttest questions. While significant pretest x pedometer interactions would have indicated the presence of pretest sensitisation, no such interactions were observed for either intention or self-reported walking. Wearing pedometers reduced intentions for future walking and coping self-efficacy. However, after controlling for pretest self-reported walking, pedometer use resulted in more self-reported walking. We conclude that wearing a pedometer increased self-reported walking behaviour but that a pretest did not differentially influence walking intentions, behaviour, or self-efficacy.     

Intra-Individual Variability Among Children with ADHD on a Working Memory Task: An Ex-Gaussian Approach

Intra-individual variability on a computer-based working memory task was examined among 25 children/adolescents with ADHD and 24 typically developing peers. Participants completed the Visual Serial Addition Task (VSAT) and reaction time data were fit to an ex-Gaussian distribution. ADHD participants demonstrated significantly more variable performance than controls, and effects of working memory load were observed. Event rate, however, had no influence on group differences in performance. Follow-up correlations revealed associations between VSAT performance and ADHD symptomatology. This study supports intra-individual variability as a hallmark feature of ADHD beyond the domain of response inhibition and reinforces the need to consider variability in ADHD more broadly.     

Elaboration and Autonomy Support in Low-Income Mothers' Reminiscing: Links to Children's Autobiographical Narratives

Maternal elaboration and autonomy support during reminiscing facilitate middle-class children's autobiographical narrative skills. In this study, low-income Hispanic, White, and Black mothers' elaboration and autonomy support in reminiscing were examined in relation to children's joint and independent autobiographical narratives and engagement. Sixty preschool children discussed three past events with their mothers and one past event with a researcher. Maternal elaboration was related to children's joint and independent autobiographical narratives, and autonomy support was related to children's joint and independent engagement. Hispanic mothers used a less elaborative style during conversations about misbehavior, and Hispanic children tended to have less advanced independent autobiographical narratives. Maternal elaboration and autonomy support appear to play different roles in children's autobiographical narratives. Further, reminiscing may serve different purposes in different racial/ethnic groups.     

Focusing on Patient Needs and Preferences May Improve Genetic Counseling for Colorectal Cancer

During cancer genetic counseling, different items which counselors consider important are discussed. However, relatively little empirical evidence exists regarding the needs and preferences of counselees. In this study needs and preferences were assessed from counselees with a personal and/or family history of colorectal cancer (CRC), who were referred for genetic counseling regarding CRC. They received a slightly modified version of the QUOTE-GENE^ca questionnaire prior to their first visit to the Hereditary Cancer Clinic. Response rate was 60 % (48/80 participants). Counselees rated the importance of 45 items assessing their needs and preferences regarding the content and process of genetic counseling. Participants rated the items regarding discussion of information about their familial CRC risk (100 %) and preventive options (98 %) as important or very important. Fewer participants rated items concerning general information on genetics as important. Sensitive communication during counseling was considered very important by a large percentage of counselees. Generally, no major differences were seen between participants in relation to individual characteristics. Our data suggest that focusing on familial CRC risk and surveillance options, in combination with sensitive communication may lead to better satisfaction with genetic counseling.     

International Genetic Counseling Students’ Perspective on Their Training Experience in the United States

International students face social, psychological and academic challenges upon moving to a foreign country to pursue higher education. Clinical disciplines such as genetic counseling present additional challenges adapting to an unfamiliar health care system and different interactions and expectations with patients and colleagues. This study used semi-structured interviews to identify challenges that international genetic counseling students face during training in the United States. Eight international genetic counseling alumni who graduated from U.S.-accredited programs were interviewed. Participants stated that the U.S. academic system was unfamiliar—class participation and paper-writing required the greatest adjustment. There was a need for help in understanding social norms in academic settings. Clinically, they were unfamiliar with the dynamics and communication style of U.S. families. Non-native English speakers experienced greater difficulty in all areas. Most participants reported that they were uncomfortable asking for help in transitioning to life, study and work. Participants identified mentorship programs for international students as potentially useful in clarifying expectations in academic and clinical settings. These results may assist international students preparing to study genetic counseling in the U.S. and may help genetic counseling training programs identify the academic and clinical challenges faced by international students.     

Reliability and Validity of the Dyadic Observed Communication Scale (DOCS)

We evaluated the reliability and validity of the Dyadic Observed Communication Scale (DOCS) coding scheme, which was developed to capture a range of communication components between parents and adolescents. Adolescents and their caregivers were recruited from mental health facilities for participation in a large, multi-site family-based HIV prevention intervention study. Seventy-one dyads were randomly selected from the larger study sample and coded using the DOCS at baseline. Preliminary validity and reliability of the DOCS was examined using various methods, such as comparing results to self-report measures and examining interrater reliability. Results suggest that the DOCS is a reliable and valid measure of observed communication among parent-adolescent dyads that captures both verbal and nonverbal communication behaviors that are typical intervention targets. The DOCS is a viable coding scheme for use by researchers and clinicians examining parent-adolescent communication. Coders can be trained to reliably capture individual and dyadic components of communication for parents and adolescents and this complex information can be obtained relatively quickly.