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.     

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.     

Impressions of people created by age-related qualities of their gaits

Drawing on the ecological theory of social perception, we investigated the impact of age-related gait qualities on trait impressions. In Study 1, subjects observed 5- to 70-year-old walkers depicted in point-light displays, and rated the walkers' traits, gaits, and ages. Younger walkers were perceived as more powerful and happier than older walkers. A composite of youthful gait qualities predicted trait impressions regardless of the walkers' masculine gait qualities, sex, and perceived age. In Study 2, subjects observed young adult walkers depicted in point-light displays and rated their traits, gaits, and ages. Consistent with the effects of real age found in Study 1, young adults with youthful gaits were perceived as more powerful and happier than peers with older gaits, irrespective of their masculine gait qualities, sex, and perceived age. Study 3 replicated Study 2 using displays showing walkers' full bodies and faces. A youthful gait predicted trait impressions even when subjects could discern the walkers' age and sex.     

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.     

Marital conflict and adjustment: speech nonfluencies in intimate disclosure

Speech nonfluency in response to questions about the marital relationship was used to assess anxiety. Subjects were 31 husbands and 31 wives, all white, college educated, from middle- to lower-middle-class families, and ranging from 20 to 30 years of age. Three types of nonfluencies were coded: filled pauses, unfilled pauses, and repetitions. Speech-disturbance ratios were computed by dividing the sum of speech nonfluencies by the total words spoken. The results support the notion that some issues within marriage are more sensitive and/or problematic than others, and that, in an interview situation, gender interacts with question content in the production of nonfluencies.     

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.     

Developmental changes in attentional skills: the effect of irrelevant variations on encoding and response selection

The present experiments examine how irrelevant variations within a stimulus set interfere with performance in a selective attention task. Second graders, fifth graders, and adults were administered a discrete trial version of a selective attention task in which they were required to search for an object that matched the prime on the targeted dimension. The stimuli in the first experiment were constructed from spatially integrated dimensions whereas the second experiment used spatially separated dimensions. The results indicated that while the spatially separated dimensions were perceived independently by all age groups, developmental differences in perceived structure were evident with the spatially integrated dimensions. Problems associated with response selection were a major source of interference with both types of stimuli, but the severity of the interference varied with the age of the perceiver and the nature of the stimuli. The developmental implications of these findings were considered.