Moving the Arm at Different Rates: Slow Movements are Avoided

Qualitative and quantitative changes characterize locomotion and rhythmic interlimb coordination at different speeds. Legs and hands do not move more or less quickly; they also adopt different relative coordination patterns. In the present article, the authors asked whether similar transitions occur for unimanual hand movements when speed is slowed below the preferred speed. Participants moved a handheld dowel back and forth between 2 large circular targets in time with a metronome at periods between 370 ms and 1667 ms. The authors analyzed the kinematics of participants’ movements at each period and found that proportional dwell time and number of peaks in the velocity profile increased as driving periods increased. Path lengths and peak velocities remained relatively constant for driving periods exceeding 800 ms. Participants made only gradual changes to their movement parameters, so that they went from a continuous mode to a more discrete mode of behavior for longer driving periods. Thus, unlike for rhythmic bimanual movements or locomotory patterns, there are quantitative but no clear qualitative changes for unimanual movements. The results suggest that participants tried to move close to their preferred tempo at different rates, and that they avoided moving slowly.     

Alienation Among the Visually Impaired: Some Important Predictors

We evaluated the effectiveness of a nondiet approach designed to reduce restrained eating behaviors and improve self-acceptance and self-esteem. This approach also encourages participants to address eating and exercise behavior separately. Subjects were Conoco employees who participated in the Wellness Department's Eat For L.I.F.E. (Long-term change; Image of self; Fun; Enjoyment of eating) program and completed pre-participation and 3-year follow-up questionnaires (N = 79). Pre- and postsurvey data were used to assess participants eating behavior, dieting behavior, self-acceptance, self-esteem, level of physical activity, and demographic information. Mastery of the internally directed eating style was assessed during the program at 3 months, at the conclusion of the 6-month program, and at the 3-year follow-up. Analysis of variance indicated that Eat For L.I.F.E. participants were able to significantly decrease their restrained eating behavior and increase self-acceptance, self-esteem, and level of physical activity. Participants also were able to adopt many aspects of the nonrestrained, internally directed eating style and decrease their frequency of weighing-in behavior. These results indicate that strategies fostering internally directed eating behaviors may be more centrally related to an individual's well-being than programs supporting externally directed eating behaviors.     

The Internal Consistency of Moral Reasoning: A Multitrait-Multimethod Assessment

The consistency of moral judgment across five dimensions (immanent justice, moral realism, retribution vs. restitution, efficacy of severe punishment, and communicable responsibility) from two basic, structural components of the cognitive-developmental approach was examined. The two components were (a) the more general concept of level and (b) the more specific concept of stage. Multitrait-multimethod analysis supported the compatibility between the two constructs. The methods differed in their degree of association between the five measured dimensions; the stage technique appeared to be more consistent than the level scale. Finally, comparisons between dimensions indicated that the notion of moral development seems to be multidimensional, vis-à-vis unidimensional, as originally implied by Piaget and later by Kohlberg.     

Influence of Passive Rotation on the Intonation of the Voice

Seventy-two subjects were randomly drawn across grades K-2 and administered an instrument designed to measure developmental skills within seven skill area categories. A three-way ANOVA, fixed effects model, was used for data analysis. Subjects were blocked by eye color, sex, and grade level for the purpose of investigating the relationship between eye color and sex to self-paced and reactive behaviors. Significant differences were obtained on the main effect of eye color in five of the seven categories examined. There were three significant first order interactions (sex × eye color) and one three-way interaction. The findings support the hypothesis of Worthy that eye color is a dependable predictor of subjects' general behavioral competency area (self-paced or reactive) and adds considerable support for his thesis that self-paced and reactive behaviors are to some degree inherited.     

Age Differences in Day-To-Day Speed-Accuracy Tradeoffs: Results from the COGITO Study

We examined adult age differences in day-to-day adjustments in speed-accuracy tradeoffs (SAT) on a figural comparison task. Data came from the COGITO study, with over 100 younger and 100 older adults, assessed for over 100 days. Participants were given explicit feedback about their completion time and accuracy each day after task completion. We applied a multivariate vector auto-regressive model of order 1 to the daily mean reaction time (RT) and daily accuracy scores together, within each age group. We expected that participants adjusted their SAT if the two cross-regressive parameters from RT (or accuracy) on day t-1 of accuracy (or RT) on day t were sizable and negative. We found that: (a) the temporal dependencies of both accuracy and RT were quite strong in both age groups; (b) younger adults showed an effect of their accuracy on day t-1 on their RT on day t, a pattern that was in accordance with adjustments of their SAT; (c) older adults did not appear to adjust their SAT; (d) these effects were partly associated with reliable individual differences within each age group. We discuss possible explanations for older adults’ reluctance to recalibrate speed and accuracy on a day-to-day basis.     

Metamemorial Knowledge of Good and Poor Readers: A Developmental Perspective

Torgesen (1977b) suggested that reading-disabled children exhibit passivity in learning situations; they fail to employ strategies that enhance learning. Such passivity resembles that of young children who lack awareness of the utility of strategies that enhance cognitive efficiency in a variety of situations (e.g., listening, reading, and memory tasks). Such awareness is one aspect of metamemory, and children with reading problems may lag behind other children with regard to this aspect. Good readers (second-, third-, and fifth-graders) and poor readers (third- and fifth-graders) were interviewed to determine their level of knowledge about a number of variables that affect memory in real-life situations. Each child was asked questions concerning his or her memory ability, and then was shown pictures depicting manipulations of the variables number, time, category, and strategy, as well as two-way combinations of the four variables. Results generally failed to support the developmental lag hypothesis. Poor readers did not resemble younger children in their awareness of variables that affect memory but exhibited knowledge commensurate with that of good readers in the same grade.     

Effects of Visual Information and Task Constraints on Intersegmental Coordination in Playground Swinging

The authors investigated how and to what extent visual information and associated task constraints are negotiated in the coordinative structure of playground swinging. Participants (N = 20) were invited to pump a swing from rest to a prescribed maximal amplitude under 4 conditions: normal vision, no vision, and 2 visual conditions involving explicit phasing constraints. In the latter conditions, participants were presented with a flow pattern consisting of a periodically expanding and contracting optical structure. They were instructed to phase the swing motion so that the forward turning point coincided with either the maximal size (enhanced optical flow) or the minimal size (reduced optical flow) of the presented flow pattern. Removal of visual information clearly influenced the swinging behavior, in that intersegmental coordination became more stereotyped, reflecting a general stiffening of the swinger. The conditions involving explicit phasing requirements also affected the coordination, but in an opposite way: The coordination became less stereotyped. The two phasing instructions had differential effects: The intersegmental coordination deviated more from normal swinging (i.e., without phasing constraints) when optical flow was enhanced than when it was reduced. Collectively, those findings show that visual information plays a formative role in the coordinative structure of swinging, in that variations of visual information and task constraints were accompanied by subtle yet noticeable changes in intersegmental coordination.     

Distance and Movement Time Effects on the Timing of Agonist and Antagonist Muscles

The experiment examined the effects of movement time (MT) and distance on the timing of electromyographic (EMG) activity from an agonist and antagonist muscle during rapid, discrete elbow movements in the horizontal plane. According to impulse-timing theory (Wallace, 1981) MT, not distance moved, should have a pronounced effect on the timing of EMG activity (duration of initial agonist and antagonist burst and time to onset of initial antagonist burst). The levels of MT were 100 and 160 msec and the levels of distance were 27° and 45° of elbow flexion. In general support of impulse-timing theory, the results of the three EMG timing measures showed that MT had a more pronounced effect on these measures than distance. In addition, the timing of EMG activity in relation to total MT remained fairly consistent across the four MT-distance conditions.     

Attentional Demands Associated With Postural Control Depend on Task Difficulty and Visual Condition

The authors aimed to assess the effect of vision on variations in attentional resources allocated to postural control during tasks of various levels of difficulty. Test-retest reliability of postural and cognitive parameters was also evaluated. Twenty adults stood quietly on a force platform during 30-s trials (primary task). Twelve conditions involving combinations of three bases of support, two vision conditions, and the presence or absence of a simple reaction time task (secondary task) were tested. Baseline trials of the reaction time task were also performed with the participants seated. Reaction time and postural parameters demonstrated good to excellent test-retest reliability in most conditions. Postural control was altered by the reduction of the base of support and by the absence of vision. Maintaining an upright stance increased reaction time compared with a seated position, indicating that quiet standing tasks required some attention even in young adults. Changes in postural steadiness were correlated with changes in reaction time, showing a significant relationship between the difficulty of the postural task and the attentional resources allocated to postural control. However, reaction time increased with the reduction of the base of support only without vision. This dual task paradigm showed that vision can compensate for the increase in attentional demands during the most difficult postural tasks.     

Gender-Specific Movement Strategies Using a Computer-Pointing Task

Females typically demonstrate a movement time advantage for tasks requiring high levels of manual dexterity, whereas males are notably better at targeting activities. According to D. Kimura (2000), the hunter-gatherer hypothesis primarily accounts for those performance advantages; that dichotomy fails, however, when one makes movement outcome predictions for tasks that are not clearly fine-motor or interceptive in nature. Investigators have recently proposed that time constraints (M. Peters, 2005) and gender-specific response style differences (M. Peters & P. Campagnaro, 1996; L. E. Rohr, 2006) affect motor performance. Here, the author used a computer-pointing task measuring both movement error and movement time in 16 participants to further investigate response style differences. Kinematic and linear regression analyses between resultant error and both movement time and task difficulty reinforced the notion that gender-specific movement biases emphasize speed and accuracy, respectively, for men and women.