Some Thoughts Regarding the Sensitivity of t to Error in Estimated Within-Group Variance

A. J. Riopelle (2003) has eloquently demonstrated that the null hypothesis assessed by the t test involves not only mean differences but also error in the estimation of the within-group standard deviation, s. He is correct in his conclusion that the precision of the interpretation of a significant t and the null hypothesis tested is complex, particularly when sample sizes are small. In this article, the author expands on Riopelle's thoughts by comparing t with some equivalent or closely related tests that make the reliance of t on the accurate estimation of error perhaps more salient and by providing a simulation that may address more directly the magnitude of the interpretational problem.     

Effects of Frustration Increase and Decrease on Percentage of Short Interresponse Times

The finding by H. L. Armus (1986) that short (less than 1 s) interresponse times (IRTs) occur with greater frequency at higher levels of required lever-pressing effort was investigated. It has been hypothesized that greater percentages of short IRTs at higher effort requirements are an expression of frustration (S. Boyer & R. Carroll, 1980); in the present study, between-groups manipulations of effort and reward combinations were made in an attempt to increase and decrease relative frustration and thereby increase and decrease percentages of short IRTs. The subjects were 17 experimentally naive, male Long-Evans rats. Manipulation of effort requirements and reward magnitudes yielded both an increase and a decrease in percentage of short IRTs. The rats switched from low effort and high reward to high effort and low reward demonstrated the greatest increase in percentage of short IRTs, whereas the rats switched from low effort and low reward to high effort and high reward demonstrated a decrease in short IRTs.     

The Relationship Between Balance Confidence and Cognitive Motor Interference in Individuals With Multiple Sclerosis

The authors examined and compared the development of oral and manual force control in preschool-aged children. In all, 50 typically developing children (aged 3-5 years) performed maximal strength tasks and submaximal visually guided tasks using tongue elevation, power, and precision grips. Dependent measures included strength, rate of force rise, initial force overshoot, force variability, and rate of force release. The authors performed age- and performance-related analyses. Results revealed similar changes for tongue, fingers, and hands across age- and performance-related measures for strength, initial force overshoot, and rate of force release. There were no significant changes in rate of force rise with increasing age. Force variability measures showed effector-specific changes with decreases across age- and performance-related measures for the hands and fingers but not for the tongue. Changes common across effector systems likely reflect biological development coupled with cognitive-strategic development. Effector-specific changes in force variability likely reflect experience gained through functional tasks influencing biological and cognitive-strategic development. Lack of change in force variability of the tongue suggests that fine control of the tongue is activity specific; thus, nonfunctional tasks are not likely to be sensitive to experience-related biological development.     

Response Complexity and the Latency of Different Movement Patterns

Two series of experiments are described in which RT of responses of varying complexity is investigated. Complexity of arm movements was manipulated in terms of (a) the amount of force exerted in resisted movements, (b) the distance moved by the limb and the direction of movement, using reversing or continuing movements, and (c) the combining of the arms in reversing and continuing movements. Simple and two-choice RT situations were used. As response complexity increased in terms of the number of sets of response units that have to be organized into a spatio-temporal sequence, the latency correspondingly increased. However latency was not affected by changes in the amount of force exerted, or in simple reversal movements. The implications of these results are discussed.     

Young Freud's linkage with Persia

Abstract

Sigmund Freud's hands helped to mutilate a volume containing a series of “colored plates” like the one replicated in Figure 1 in the text. As a young adult, his personal library included a fairytale whose German text was entitled Die Träumleiter: Ein Marchen. No one has yet been able to authenticate the author's identity beyond the following imprint: “S. Andreas (1832).” The poetic play centers upon a celestial meeting featuring Shakespeare, Goethe, and Dschami. It has been translated into English (The dream ladder: A fairy tale), but still awaits a psychoanalytically informed exegesis.     

Illness perceptions and coping explain well-being in patients with Huntington's disease

This study sought to investigate the contribution of illness perceptions and coping mechanisms to the explanation of well-being of patients with Huntington's disease (HD). We investigated the Leventhal et al. assumption of the Self-regulation Model that coping mediates the relationship between illness perceptions and patients’ well-being. Illness perceptions, coping, and well-being in 77 HD patients were assessed with validated questionnaires; motor performance and cognitive performance were assessed with Huntington's disease-specific measures. The assumption that illness perceptions influence HD patients’ well-being via coping was not supported. The results indicate that both coping and illness perceptions made a major contribution to the explanation of variance in HD patients’ psychosocial well-being. Variance in their physical well-being was explained by illness perceptions mainly. The need to conduct further research on the interrelationships between illness perceptions, coping, and well-being in this patient category is discussed.     

Racism‐Related Stress,General Life Stress,and Psychological Functioning Among Black American Women

The relationship between general life stress, perceived racism, and psychological functioning was explored in a sample of 118 Black American women. Findings indicate that racism‐related stress was not a significant predictor of psychological functioning when controlling for general life stress. Perceived racism was positively associated with general life stress. Implications for practice and future research are discussed. La relación entre el estrés general de la vida, el racismo percibido y el funcionamiento psicológico se exploraron en una muestra de 118 mujeres afroamericanas. Los resultados indican que el estrés relacionado con el racismo no fue un pronosticador significativo del funcionamiento psicológico cuando se controló estadísticamente para tomar en cuenta el estrés general de la vida. El racismo percibido estuvo asociado positivamente con el estrés general de la vida. Se discuten las implicaciones para la práctica e investigaciones futuras.     

Measuring the impact on relatives of caring for people with Alzheimer's disease: Quality of life,burden and well-being

Abstract

This study compared key correlates of caregiver stress in 50 Alzheimer's disease patients and their primary caregivers. in relation to three outcome measures - perceived burden, psychological well-being, and quality of life (QoL). These were evaluated using the Zarit Burden Interview. General Health Questionnaire (GHQ-30), and Schedule for the Evaluation of Individual QoL (SEIQoL-DW) respectively. Informal social support was evaluated on Vaux's Social Support Appraisal Scale. Patients' cognitive. functional, and behavioural status were rated on Mini-Mental State Examination, Blessed-Roth Dementia Scale. and Baumgarten Dementia Behaviour Disturbance Scale respectively. Standardised multiple regression analysis was used to compare the outcome measures. In this model burden was highly related to behaviour disturbance. and also to social support (adjusted R² = 0.45). Well-being was significantly related to behaviour disturbance, and also to functional status (adjusted R² = 0.40). With regard to QoL the model performed poorly as most of the variance in QoL was not accounted for by the model (adjusted R² = 0.14). These findings highlight differences in factors determining caregiver QoL. burden and well-being.     

A randomised controlled trial of the effects of implementation intentions on women's walking behaviour

The combination of low physical activity rates and increased cardiovascular deaths indicate the overwhelming need for behaviour change interventions that can effectively promote physical activity among sedentary women. This 11-week randomised controlled trial examined the effects of an implementation intentions intervention on sedentary women's walking behaviour. Seventy-five women (M age = 48.17) were randomly assigned to either a control group where they were required to self-monitor their daily pedometer-determined step count or to an experimental group where they were asked to form specific walking plans (i.e. implementation intentions) every 6 weeks and to self-monitor their daily pedometer-determined step count. Measures of exercise intentions, perceived behavioural control, scheduling and barrier self-efficacy were administered at baseline, week 6 and week 11. Analyses indicated higher step counts over the first 6 weeks for women in the experimental condition (p < 0.02). Furthermore, higher self-efficacy to schedule (p < 0.01) and overcome walking barriers (p < 0.03), as well as higher perceptions of behavioural control (p < 0.02) were found at week 11 for women in the experimental versus control condition. However, none of the control beliefs were found to mediate the effects of the intervention on the women's walking behaviour. Furthermore, the intervention did not have any effect on the strength of the goal intention–behaviour relationship. The findings suggest implementation intentions are an effective strategy for initiating leisure-time walking within sedentary women.