Stephen B. Hillman

Power of the Independent Samples t Test under a Prevalent Psychometric Measure Distribution.

Studies in psychology often have low power because of inadequate sample size. Thus, recent articles in this journal have suggested making sample size determinations through readily available tables that are based on population normality. Questions have been raised on the use of these power tables because prevalent psychometric distributions, such as the discrete mass at zero with gap that occurs with first use or onset variables, are radically nonnormal. In addition to demonstrating the robustness of the independent samples t test with respect to type I error, the major finding of this study shows that researchers may use these power tables without modification for this radically nonnormal distribution.

Externalization as a Self-Protective Mechanism in a Stigmatized Group

The Nowicki-Strickland measure of internal-external locus of control was administered to 110 African-American adolescents. Analysis indicated high externalization, even though these students had a higher than average self-concept.

Multidimensional Differences between Adolescent Substance Abusers and Users

High-school-aged adolescents responded to a 48-item survey about their substance use. From an original sample of 190 respondents, groups were created through consequence variables (e.g., school, family, medical, and legal problems) into abuse (n = 41) and use (n = 115) categories. Variables were organized along multidimensional lines: stimulus (e.g., frequency of substance use, use in school), organismic (e.g., age, grade), and response (e.g., driving a car while under the influence). From 27 comparisons of the abuse and use groups 16 significant differences emerged.

Risk perception: unrealistic optimism or realistic expectancy.

The current study investigated risk perception and Unrealistic Optimism as a function of involvement in risk. 74 undergraduate students were asked to rate how likely they were to encounter various negative consequences relative to various comparison targets (child, peer, and parent) and specified their actual involvement in risk-taking. Over-all, 37 High and 37 Low Risk-takers rated harmful events similarly, adding support for disputing the hypothesis that risk-takers consider themselves to be invulnerable. When these older adolescents compared themselves with children, they rated their personal risk of engaging in the health threatening behaviors as higher. Adolescents can realistically appraise the differences between themselves and children and view themselves as more likely to encounter the negative outcomes of risk-taking behaviors. Implications are discussed.

The mediating impact of coping style on stress perception for parents of individuals with intellectual disabilities

Research reveals that parents of individuals with intellectual disabilities experience more stress than parents of persons of normal development. The majority of previous research has measured direct relationships between stress variables and stress perception and little attention has been given to the impact of mediating variables. The present study utilized an indirect pathway model to examine the mediating influence of coping style on the relationship between social support, severity of child disability, parental optimism and stress perception for these parents. Parents of individuals receiving mental health services through an agency in Southeastern Michigan participated in the study. Results indicated that coping style partially mediated the relationship between social support and stress perception for parents of individuals with intellectual disabilities.

Personality and drug abstention in adolescents

Personality and drug abstention in adolescents were investigated in a sample of 292 high school seniors. A significant difference was found between abstention and low scores for novelty-seeking behavior based on responses to the Tridimensional Personality Questionnaire. Those who reported abstaining from alcohol had significantly higher grade point averages, attended religious services significantly more frequently, and considered religion significantly more important than those who reported drug use and abuse.

Eye dominance and somatosensory asymmetry in relation to motor asymmetry: Evidence from hemiplegic children

Fifty‐four children with congenital hemiplegia (25 left and 29 right hemiplegics) were administered a battery of sensory and perceptual tests, the results of which were related to measures of motor asymmetry obtained from the same children. Asymmetries of visual acuity and eye dominance were largely independent of motor asymmetry. Asymmetries of stereognosis and finger identification, but not graphesthesia, were associated with various measures of motor asymmetry. It appears that the association between tactile and motor asymmetries varies with the motor demands of the tactile task and that there is little intrinsic relationship between somatosensory and motor asymmetry. Even though the development of motor skill in these children was more impaired by left‐hemisphere damage than by right‐hemisphere damage, left‐and right‐hemisphere damage produced equivalent deficits in their sensory and perceptual ability.

Motor asymmetries in hemiplegic children: Implications for the normal and pathological development of handedness

Hemiplegic children are an important source of information about hemispheric specialization for linguistic and cognitive processes, but little attention has been given to the hemiplegia itself. In this study we describe several aspects of motor laterality—hand and foot preference, hand differences in proficiency on three manual tasks, and asymmetry of hand and foot size—in 30 right‐hemiplegic and 27 left‐hemiplegic 4‐ to 14‐year‐olds. Whereas most children showed extreme hand and foot preference, asymmetries of manual performance and hand and foot size approximated the normal distribution. Most asymmetries remained constant with increasing age. When compared with left hemiplegics, right hemiplegics showed poorer manual performance and lower correlation of asymmetry scores across different tasks. The results suggest that manual specialization is determined early in development and that the ability to compensate for impairment of the right hand is limited.

Comparison of Self-Esteem Scores: American and Indian Adolescents

The Coopersmith Self-esteem Inventory was administered to 112 African American adolescents who were academically at-risk for dropping out of high school. Results were similar to those of a previous study comparing a heterogeneous group of 100 American adolescents with 100 youths from India. Differences on scores of self-esteem for the two international groups were noted.

Effects of maternal employment patterns on adolescents' substance use and other risk-taking behaviors

Employment for mothers with school-age children has generated great concern regarding its possible harmful effects on adolescents and their families. We examined the influence of maternal employment on the risk-taking behavior of adolescents in two-parent families. Three hundred and eighty-nine high school students completed a 48-item survey in which they indicated their mothers and fathers employment patterns, and their own risk-taking behaviors (e.g., substance use, driving while under the influence). Results showed no significant effects of maternal employment on adolescent risk-taking behaviors.