The role of visual information in control of a constrained locomotor task

The nature of visually guided locomotion was examined in an experiment where subjects had to walk to targets under various conditions. Target distance was manipulated so that subjects had to (a) lengthen their paces in order to hit the target; (b) shorten their paces; (c) make no adjustments to their standard pace length at all. They did this under four visual conditions: (a) normal vision; (b) with vision restricted to a "snapshot" each time the foot that was to be placed on the target was on the ground; (c) with a snapshot each time the foot to be placed was in the swing phase; and (d) no vision after departure fro the target. The results show that the subjects succeed in reaching the target in most cases. However, the smoothness and fluidity of their movements vary significantly between conditions. Under normal vision or where visual snapshots are delivered when the pointing foot is on the ground, locomotion is smoothly regulated as the subjects approach the target. where snapshots are delivered when the pointing foot is in the swing phase, regulation becomes clumsy and ill coordinated. Where no vision is available at all during the approach, adjustments are made, but these are least coordinated of all. The results show that well-coordinated visual regulation does not require continuous visual guidance but depends on intermittent information being available at the appropriate times in the action sequence. Such timing is often more important than the total amount of information that is available for guidance.     

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.     

Shared knowledge about infants among fathers and mothers

Evidence for the exchange of parenting information between low-income White mothers and fathers of infants was found. Mothers had more accurate expectations for normative development than fathers, but more accurate fathers had spouses who were also more accurate--even when education was controlled. Though few significant differences were evident in help-seeking behavior when infant problems were encountered, fathers turned to fewer helpers than mothers and were somewhat more likely to rely solely on their spouse. These data indicate that researchers must consider the exchange of information between spouses, particularly when studying the socialization of parenting among fathers at this stage in the life cycle of the family.     

Effects of a structured behavior modification treatment program on locus of control in behaviorally disturbed children

The effect of a 10-day behavior modification treatment program on locus of control was investigated. The subjects were children (N = 130; 6 to 12 years old) with severe behavioral disorders who were predominantly from low socioeconomic backgrounds, from broken homes, and socially deprived. Pre- and post-testing was done with the Nowicki-Strickland Preschool and Primary Internal-External Control Scale (Nowicki & Duke, 1974) and the Nowicki-Strickland Locus of Control Scale for Children (Nowicki & Strickland, 1973). Children between the ages of 10 and 12 responded to therapy with a significant increase in internality, but younger children did not.     

Finding the face in the crowd: an anger superiority effect

Facial gestures have been given an increasingly critical role in models of emotion. The biological significance of interindividual transmission of emotional signals is a pivotal assumption for placing the face in a central position in these models. This assumption invited a logical corollary, examined in this article: Face-processing should be highly efficient. Three experiments documented an asymmetry in the processing of emotionally discrepant faces embedded in crowds. The results suggested that threatening faces pop out of crowds, perhaps as a result of a preattentive, parallel search for signals of direct threat.     

The Effect of Job Level and Amount of Information on the Evaluation of Male and Female Job Applicants

The addition of job-related information regarding an applicant's leadership ability reduced bias against female applicants applying for a managerial position.     

Children's perception of certain musical properties: scale and contour

Children's perception of scale and contour in melodies was investigated in five studies. Experimental tasks included judging transposed renditions of melodies (Studies 1 and 3), discriminating between transposed renditions of a melody (Study 2), judging contour-preserving transformations of melodies (Study 4), and judging similarity to a familiar target melody of transformations preserving rhythm or rhythm and contour (Study 5). The first and second studies showed that young children detect key transposition changes even in familiar melodies and they perceive similarity over key transpositions even in unfamiliar melodies. Young children also are sensitive to melodic contour over transformations that preserve it (Study 5), yet they distinguish spontaneously between melodies with the same contour and different intervals (Study 4). The key distance effect reported in the literature did not occur in the tasks of this investigation (Studies 1 and 3), and it may be apparent only for melodies shorter or more impoverished than those used here.     

Effects of Social Demand on Reports of Self-Monitored Blood Glucose in Adolescents with Type 1 Diabetes Mellitus

The purpose of this study was to test the hypothesis that social demand could substantially affect reports of self-monitored blood glucose (BG) in adolescents with insulin-dependent diabetes mellitus. Of 34 patients initially enrolled in the study, 10 were excluded because they did not bring any BG records with them to an outpatient clinic appointment. The remaining 24 patients were randomly assigned to either a low or high social demand condition that provided instructions for monitoring of BG for the week following the appointment. The subjects' BG records were quantified to provide frequency of measurement and mean reported BG for the week prior to and after the clinic visit. Five subjects did not return their BG records for the week following the intervention. The analyses were therefore based on the 19 subjects from whom complete records were obtained. The 12 subjects in the low social demand group and 7 subjects in the high social demand group were equivalent with regard to age, duration of diabetes, socioeconomic status, and glycosylated hemoglobin. Frequency of BG measurement was similar in both groups during both weeks. The mean BG value reported in the week prior to intervention was similar for the groups. However, analyses of the post-intervention BGs revealed that subjects in the low-demand group reported significantly higher BGs compared to pre-intervention and to subjects in the high-demand group. These findings suggest that self-monitoring and reporting of BG is a social behavior that is affected by the demand characteristics of the interpersonal patient-health provider relationship. Because optimal treatment planning for individuals with diabetes requires accurate BG records, care must be taken to interpret them in light of the social demand characteristics associated with clinical assessment.     

PROMPTING ONE LOW-FAT,HIGH-FIBER SELECTION IN A FAST-FOOD RESTAURANT

Evidence increasingly links a high-fat, low-fiber diet to coronary heart disease and certain site cancers, indicating a need for large-scale dietary change. Studies showing the effectiveness of particular procedures in specific settings are important at this point. The present study, using an A-B-A-B design and sales data from computerized cash registers, replicated and extended previous work by showing that inexpensive prompts (i.e., signs and fliers) in a national fast-food restaurant could increase the sales of salads, a low-fat, high-fiber menu selection. Suggestions also are made pertinent to more widespread use of the procedures.