The development of locomotor coordination: longitudinal change and invariance

Developmental sequence, relative timing, center of gravity, and phase-plane analyses were used to study a minimum of 15 years of longitudinal, filmed data on the development of hopping in 7 children. The developmental sequences revealed common, qualitative changes in the movement of the children, although each child progressed through the changes at his/her own rate. The timing analyses showed that, in the advanced hop, the tightest limb relationships were found within the hopping leg, then between contralateral limbs of the same girdle, and then between legs and arms. Relative-timing calculations revealed (a) intralimb, timing invariances that were present in first attempts to perform the skill at age 3 and remained for 15 years across all developmental levels; (b) emergent, interlimb timings that gradually became invariant; and (c) intra- and interlimb timing showing gradual development over the 15 years. One invariant, the time between landing and deepest knee flexion, is also invariant in the walk and the run (Shapiro, Zernicke, Gregor, & Diestel, 1981). Phase plane analyses indicated that the timing of peak and zero velocities may be the coordinative constant accounting for a relative timing invariance between the two legs. Position of the body's center of gravity may explain the invariant relative time between landing and deepest knee flexion, or the explanation could lie in the "equation of constraint" regulating joint equilibrium points. The data suggest that modeling the developing hop as the evolving interaction of four vibratory systems would be promising.     

A "change-of-standard" perspective on the relations among context, judgment, and memory

We conducted three studies that tested a "change-of-standard" perspective on the relations among context, judgment, and recall. Each study consisted of two or three sessions held a few days apart. All subjects read about the sentencing decisions of one or two target trial judges and of six nontarget trial judges who consistently gave either higher or lower sentences than the target judge(s). Each study varied both the standard that was available when subjects initially judged the sentencing decisions of a target judge and the standard available when subjects subsequently recalled those decisions. To accomplish this, we varied the context of judgment, the timing of judgment, and the overall category norm for trial judges' sentencing decisions that was available at recall. We found that although subjects had been exposed to the same target information and had initially judged it in the same way, their recall of the information was different depending on whether and how a change-of-standard had occurred between judgment and recall. Unique predictions of the change-of-standard perspective were confirmed that could not be accounted for in terms of other types of context effects on judgment and memory.     

Specific forms of facial EMG response index emotions during an interview: from Darwin to the continuous flow hypothesis affect-laden information processing

Previous research has demonstrated that mild negative emotional imagery and unpleasant sensory stimuli lead to greater electromyographic activity over the brow muscle region than mild positive imagery and stimuli, even in the absence of significant changes in visceral and general facial EMG activity. Previous research has not addressed whether electromyographic responses over the brow region are a sensitive and specific index of emotions, however, since a multiplicity of events lead to changes in brow activity. In this research, facial electromyographic and audiovisual recordings were obtained while individuals were interviewed about themselves. Afterwards, individuals were asked to describe what they had been thinking of during specific segments of the interview marked by distinctive electromyographic responses over the brow region in the context of ongoing but stable levels of activity elsewhere in the face. The results are interpreted in terms of a continuous flow hypothesis of affect-laden information processing.     

Differences Between Personal Estimates of Body Fatness and Measures of Body Fatness in 11- and 12-Year-Old Males and Females

This study was designed to assess the accuracy of perceived levels of body fatness as indicated by 11- and 12-year-old children. Using a rating scale ranging from 1 (extremely lean) through 9 (extremely overweight), 50 males and 50 females estimated personal levels of body fatness. Using a 2 × 2 between-and-within-groups ANOVA, these estimates were compared to individual skinfold sum percentile scores derived from comparisons with national skinfold norms. The results revealed that the females tended to overestimate personal levels of body fatness, whereas estimates given by the male subjects were interpreted as not significantly different from skinfold sum percentile scores.     

Encoding and retrieval processes in learning-disabled, head-injured, and nondisabled young adults

Using a multi-trial, free-recall paradigm (Rey Auditory-Verbal Learning Test; Lezak, 1983), the acquisition and retention by learning disabled (LD) young adults with a Halstead Impairment Index less than or equal to 0.3 (low LD) or greater than or equal to 0.4 (high LD) was compared with that of nondisabled and head-injured (HI) young adults. Significant group differences, particularly during the last three acquisition trials, confirmed the effectiveness of this method in revealing subtle learning and retention deficits. Analyses of Trial 1 recall showed group differences in the prerecency but not the recency portion of the serial position curve, thus implicating long-term but not short-term memory differences between the groups. Analyses of pair frequency (Sternberg & Tulving, 1977) data showed that the three clinical groups had difficulty organizing the to-be-learned material for effective retrieval. Following an interpolated task, retention was poorer for the clinical groups than for the nondisabled and varied inversely with the degree of neuropsychological impairment. Finally, during retention, the nondisabled and low LD groups retained and used the list organization established during acquisition whereas the high LD and HI groups did not.     

Preventing Substance Abuse Among American-Indian Adolescents: A Bicultural Competence Skills Approach

Tobacco, alcohol, and drug use are problems for American-Indian people. We reviewed these problems and the explanations for them and described a bicultural competence skills approach for preventing substance abuse with American-Indian adolescents. Data from a study of that approach suggest its efficacy with American-Indian youth. At posttest and a 6-month follow-up, American-Indian subjects who received preventive intervention based on bicultural competence skills concepts improved more than did American-Indian subjects in a no-intervention control condition on measures of substance-use knowledge, attitudes, and interactive skills, and on self-reported rates of tobacco, alcohol, and drug use. Our findings have implications for future substance-abuse prevention research with American-Indian people.     

Systemic crisis intervention as a response to adolescent crises: an outcome study

The present study demonstrates the safety and effectiveness of an outpatient program designed to respond to adolescent-precipitated crises by mobilizing and restructuring the family's kinship system. Families of 75 adolescents at risk for hospitalization were followed up to 24 months after treatment with Systemic Crisis Intervention. Measures of offspring and family functioning, suicidal behavior, institutional use, and treatment costs are presented. Results clearly demonstrate the safety, effectiveness, and economic viability of Systemic Crisis Intervention.