Variation in Coordination of a Discrete Multiarticular Action as a Function of Skill Level

The authors investigated coordination modes that emerged as a function of the interaction between skill level and task constraints in a multiarticular kicking action. Five skilled, 5 intermediate, and 5 novice participants attempted to satisfy specific height and accuracy constraints in kicking a ball over a barrier. Skilled and intermediate groups demonstrated a functional coordination mode involving less joint involvement at the proximal joints and greater joint involvement at distal joints, mimicking a chip-like action in soccer. Conversely, the novice group tended to produce larger ranges of motion throughout the kicking limb in a driving-like kicking action. Key differences were also found for task outcome scores, joint angle-angle relations, and ball-trajectory plots between the skilled and intermediate groups and the novice group. Findings from this study demonstrated that joint involvement during this discrete multiarticular action is a function of skill level and task constraints rather than a consequence of a global freezing-freeing strategy suggested in some previous research. The authors also highlight the merit of using a model of the acquisition of coordination in examining how coordination modes for multiarticular actions differ as a function of skill.     

Isofrequency and Multifrequency: Coordination Patterns as a Function of the Planes of Motion

A series of studies examine the maintenance of the relative phase of simultaneous cyclic limb movements by the manipulation of the planes of motion during isofrequency and multifrequency conditions. To evaluate predictions from a dynamic pattern approach in which differences in the limbs' uncoupled frequencies give way to competitive interactions when the limbs are moved simultaneously, Experiment 1 determined the preferred frequencies of single-limb movements during sagittal and transverse planes of motions. The results revealed that the plane in which the motion was produced significantly affected the cycle frequencies. In investigating isofrequency coordination, Experiment 2 showed that homologous limbs were more accurate in attaining the relative phasing when moving in one as compared to two separate planes, whereas no such effect was observed for non-homologous limbs. Furthermore, the planes of motion significantly influenced the variability of relative phasing such thattwo-plane motionswere less stable than one-plane motions.Experiment 3 examined the effect of the planes of motion upon multifrequency coordination and demonstrated that the homologous and homolateral limbs were less successful in producing the relative phasing when the motions were produced in one as compared to two planes, whereas this effect was not observed for the heterolateral limbs. These findings indicate that frequency detuning resulting from the planes manipulation affects the quality of phase-locking during isofrequency and multifrequency conditions, even though it may be assumed that additional neural constraints are involved in the interlimb coordination process.     

Development of Bimanual Skill: The Search for Stable Patterns of Coordination

In 2 experiments, dynamic systems theory predictions concerning intrinsic dynamics and variability of bimanual coordination were examined at different developmental stages. In Experiment 1, ten 4-, 6-, 7-, 8-, and 10-year-old children and adults performed unimanual dominant, unimanual nondominant, and bimanual continuous circle drawing. All tasks were performed at the participants' preferred rate, size, and mode of coordination. The 4-, 6-, and 7-year-old children produced larger circles with longer durations than those of the 8- and 10-year-olds and the adults. That finding demonstrates that younger children display different intrinsic dynamics than older children and adults. The 4-, 6-, and 7-year-old children also displayed more variability in bimanual coordination (more time in less stable patterns of coordination, higher standard deviation in relative phase) and produced more transitions between coordination patterns than the 8- and 10-year-olds and the adults. In Experiment 2, the same participants performed bimanual circles at increasing rates. Consistent with predictions of the HKB model (H. Haken, J. A. S. Kelso, & H. Bunz, 1985), the number of transitions decreased as speed increased. Some support was found for the notion that age-related variables of attention and rate contribute to the increased variability in young children's bimanual coordination.     

Perceptual Estimates of Motor Skill Proficiency Are Constrained by the Stability of Coordination Patterns

This study demonstrated that motor skill proficiency ratings are constrained by the same order parameter dynamics that constrain action production and action perception processes. Participants produced rhythmic actions simulated by an animated stick figure of the human arm. The primary finding was that participants’ proficiency ratings covaried most with relative phase (φ) variability compared to mean relative phase. In-phase (φ = 0°) was produced with the least variability and received the highest proficiency rating, whereas the patterns φ = ±150° were attempted with the most variability and received the lowest proficiency ratings. A temporal delay in attempting to produce the animated pattern had a large impact on produced relative phase, yet had little impact on the proficiency ratings. Proprioceptive processes provide individuals information on motor skill proficiency. The lead or lag motion of the hand to forearm segment of the animated arm was identified consistently through visual processes and revealed asymmetries in the mapping of visual input to motor output. The results are consistent with concepts from the dynamic pattern theory of coordination and are discussed with regard to relative phase as an informational variable that constraints the perception-action system across many levels.     

Coordination of Grip Configurations as a Function of Force Output

In this investigation, the authors examined the coordination and control of force production by the digits of the hand as a function of criterion force level and grip configuration. Each adult participant (N = 6: 3 men and 3 women) was required to place the thumb and a finger (or fingers) upon load cells that were fixed to a grasping apparatus that was clamped to a table. In the task, participants had to match a criterion continuous constant total force level displayed on a computer screen. There were 10 trials at each grip configuration and criterion force level combination on each of 3 consecutive days. The results showed that (a) different grip configurations minimized error at each force level; (b) there was a specific digit pairing within a given grip configuration that produced the highest correlation of force output; (c) the correlation between the force output of digits generally increased at higher force levels; (d) error was reduced at each force level and grip configuration over the practice period; and (e) the organization of the force output of each digit varied as a function of digit, force level, grip configuration, and practice. The findings are consistent with the hypothesis that coordination of the digits in prehension is reflective of an adaptive, task-specific solution that is modified with practice.     

Performance Accomplishment Information as Predictors of Self-Efficacy as a Function of Skill Level in Amateur Golf

The predictive capabilities of different types of performance accomplishment information (PAI) towards self-efficacy for amateur golfers were compared as a function of skill level. Male golfers (N = 197; skilled n = 84, lesser skilled n = 113) recorded self-efficacy levels before and after competitive golf performance. Multiple regression analyses revealed that handicap was the most significant predictor of PAI towards pre-round self-efficacy for skilled golfers while practice satisfaction was the most significant predictor for lesser skilled. Handicap achievement was a significant predictor of post-round self-efficacy for both skilled and lesser skilled golfers. The findings imply athletes of varying skill level utilize different information when developing efficacy beliefs. Further study of the relationship between PAI and self-efficacy is therefore warranted in the sports domain.     

Family interaction Patterns as a Function of Task Characteristics1

Data from two experiments were evaluated to test the widely held assumption that family process remains essentially constant regardless of the conditions under which it occurs. Significant differences and reversals in patterns of dominance between interacting husbands and wives were obtained under different task conditions. In general, stressful tasks and tasks with structured goals elicited paternal dominance, while maternal dominance of more equalitarian patterns resulted from tasks which involved discussion of feelings and opinions. These and other task dimensions were discussed. The findings of this study generate four conclusions: prior studies must be reviewed to evaluate task effects; future researchers must systematically investigate task characteristics; researchers must exercise care in the selection of tasks in future studies; and the relationship between role behaviors and task demands must be understood in order to help meet the increasing stress impinging upon the modern family system.     

Improvisation as a Meta-Counseling Skill

Counselor education tends to see the development of basic counseling and communication skills as the foundation of clinical training. Improvisation has historically and primarily been connected to theater training and as a performance mechanism. By developing skills in spontaneity and the nature of narrative (or story) one becomes more able to be in-the-moment with a client or clients and thus less anxious and more able to meet the client where they are. As such, improvisation can really be seen as a meta-counseling skill—a skill that can form a firmer foundation for the learning of the basic counseling and communication micro-skills. This article outlines the core concepts of improvisational training for counselors and includes examples of improvisational games that can specifically help in preparing counselor trainees for their future clinical work.     

Acquiring a Novel Coordination Skill without Practicing the Correct Motor Commands

There is evidence that experience of the sensory consequences, in the absence of practice of the required motor commands, is sufficient to learn new bimanual coordination patterns. This was shown through improvements of an incongruent group who practiced a desired 30° phase offset between the limbs while 1 limb was weighted such that the desired phase relation was achieved when synchronous motor commands were sent to the limbs (P. Atchy-Delama, P. G. Zanone, C. E. Peper, & P. J. Beek, 2005). In addition to testing a similar incongruent and congruent group (i.e., no weight), the authors extended this experiment by removing visual feedback during practice and by including an auditory modeling and passive guidance group. All groups showed improvement, except for the modeling group. The passive guidance group made more errors in posttests than the congruent and incongruent groups. Only the congruent group increased the amount of time around 30° after practice. Active experience of the sensory consequences combined with practice sending appropriate motor commands is the most effective method for learning, even though strategic improvements can be attained without experience of the latter.     

Discrimination of Visual Patterns as a Function of Motivation and Frequency of Reinforcement

The influence of the content of statements regarding delay and the level of role involvement (free choice of verbalization condition, assignment to verbalization condition, or passive listening to statement) on self-control in 98 preschool boys and girls was investigated in a task in which the child's possession of accumulating candy rewards was made contingent upon the child's stopping further accumulation. Children who chose to verbalize the task-centered utterance waited longer before taking the rewards than did the children in the three conditions involving reward-centered statements. Children who were told to use the task-centered statement or who passively heard it waited longer than did children who were told to use the reward-centered statement or who passively heard it. Children who chose the reward-centered statement waited less than children in the other two reward-centered conditions. Children given no direction regarding what to do during the waiting period delayed less than children in the task-centered conditions and they delayed about the same as children in the reward-centered groups, suggesting that preschoolers spontaneously employed delay plans which did not maximally facilitate self-control.     

Organization of Compensatory Postural Coordination Patterns

The authors investigated whether compensatory postural coordination patterns are organized according to the same dynamical principles as are nonequilibrium phase transitions. Eight participants were asked to maintain upright balance on a moving platform that was sinusoidally translated in the anterior-posterior direction and was systematically increased and decreased 0.19 Hz as a step function every 10 platform cycles through the frequency range 0.19–1.46 Hz. At low platform frequencies, all participants exhibited small joint angular motions with high variability, and the relative phase between the joint motions exhibited drifting patterns and large fluctuations. As platform frequency increased, the amplitude of joint motion increased systematically and joint-specific oscillatory patterns emerged. The findings provided no evidence for a Hopf bifurcation or hysteresis in the transitions of postural coordination modes, however, or, mote generally, a basis for distinguishing the relevance of linear versus nonlinear models of postural control.     

News Selection Patterns as a Function of Race: The Discerning Minority and the Indiscriminating Majority

This study examines whether White majority and Black minority members differ in selecting news stories that featured either individuals of their own group or dissimilar others. Hypotheses derived from social-cognitive theory, social comparison theory, and distinctiveness theories were tested utilizing unobtrusive observations of news story selections. This selective exposure research design overcomes methodological constraints of previous experimental studies that employed self-reports and forced-exposure techniques to measure responses of Blacks and Whites to race-specific media sources. Our sample consisted of 112 Blacks and 93 Whites, who browsed 10 online news stories while exposure was unobtrusively logged via software. The news site displayed equal numbers of Black and White characters, with the pictures associated with the news stories rotated across participants. Results indicate that Whites showed no preference based on the race of the character featured in the news story. In contrast, Blacks strongly preferred news stories featuring Blacks and spent more than twice the reading time on them compared to exposure to news stories featuring Whites.     

Performance on a Following Tracking Task (Modified Sam Two-Hand Coordination Test) as a Function of Radius of Control Cranks

The influence of two deindividuating variables, altered responsibility and coaction in groups, on one's tendency to deliver noxious or helpful stimulation impulsively and in a cyclical pattern to a target person was investigated in a laboratory experiment with use of 96 male and female junior college students. Analysis of variance revealed that, as hypothesized, Ss who coacted in groups of three and who had the responsibility for their behavior removed delivered noxious (but not helpful) stimuli more impulsively than Ss who worked alone and were made to feel responsible (p < .01). Ss responded in a more cyclical pattern when delivering aversive tones than when delivering facilitating tones (p < .005). A marginally significant finding was that Ss in groups responded in a more cyclical pattern than Ss alone only when the response was seen as aversive. It was concluded that the probability of impulsive and cyclical aggression may be increased by altered responsibility and coaction.     

The Schematic Representation of Effector Function Underlying Perceptual-Motor Skill

Conceptual and methodological problems related to Schmidt’s (1975) motor schema theory are discussed. In particular, the motor schema is interpreted as representing the dynamics of the system being controlled, which may or may not be associated with a referent movement pattern. Furthermore, it is suggested that prior familiarity with a control system’s dynamics is a critical but uncontrolled factor in tests of the theory, and largely accounts for their equivocal findings. These ideas are examined by two experiments in which subjects had to bimanually control the movement of a computer-displayed cursor along a track on a CRT screen. Different track orientations required different patterns of movement not entailing a single generalized motor program. Experiment 1 shows that variable track performance with a given control system, results in better transfer to novel tracks than does fixed practice. Experiment 2 demonstrates that altering the control system disrupts performance whether or not the required movements remain the same. These results indicate the need for a fundamental modification of schema theory, such that a schematic representation of effector-environment relations (effector function) is available independently of particular movement patterns used in its acquisition.     

Exploration and Selection of Intralimb Coordination Patterns in 3-Month-Old Infants

Through the exploration of their own capacities and the selection of adaptive responses, infants learn new motor solutions. Using a conjugate reinforcement mobile procedure, previous researchers have repeatedly shown that infants increase their leg kick frequency to control a mobile that is connected to their ankles. That traditional experimental design allows multiple motor solutions to the task and therefore provides limited information about the infants' capacity to explore and select specific motor solutions. The author designed a new experimental procedure to study infants' capacity to discover and adopt specific motor solutions. The new, constraining mobile reinforcement procedure requires a specific motor response and therefore the development of a more finely tuned perception—action map than has previously been experimentally demonstrated. To gain reinforcement from the mobile, infants had to produce a coordinated hip and knee extension within the same leg. The results from the 13 infant participants showed that they were capable of increasing their frequency of coordinated movements to make the mobile move. Those results suggest that infants at the age of 89–106 days are sensitive to intralimb coordination task requirements and are capable of mapping their own limb dynamics to the environmental information.     

Coordination changes in a discrete multi-articular action as a function of practice

This study investigated how novices re-organized motor system degrees of freedom when practicing a multi-articular discrete kicking task. Four male participants practiced a soccer chipping task to seven different target positions over 12 sessions for 4 weeks. Data from each participant indicated changes in degrees of freedom involvement as a function of practice. Further, each participant showed a different progression of change in levels of joint involvement for hip, knee and ankle in the kicking limb. Cross-correlations between joints in the kicking limb also showed different pathways of coupling and de-coupling with practice. Performance outcome scores improved and variability of intra-limb coordination decreased as a consequence of practice for all participants. Angle-angle plots also showed qualitative changes in intra-limb coordination between early and late practice sessions. Evidence suggested that foot velocity at ball contact was functionally manipulated by participants when kicking to target positions with varying height and distance constraints. Referencing data to a model of learning [Newell, K. M. (1985). Coordination, control and skill. In: Goodman, D., Franks, I., & Wilberg, R.B. (Eds.), Differing perspectives in motor learning, memory, and control. Amsterdam: North-Holland, pp. 295-317] determined that progression through different stages of learning may not be sequential and could alternate between learning stages. The present study highlighted individual differences in acquisition of coordination and control of joint motion even under similar task constraints, showing how degeneracy in movement systems facilitates learning.     

Intentional Switching Between Patterns of Bimanual Coordination Depends on the Intrinsic Dynamics of the Patterns

Two predictions arising from previous theoretical and empirical work which demonstrated that spontaneous changes of bimanual coordination patterns result from a loss of pattern stability (i.e., a nonequilibrium phase transition) were tested: (a) that the time it takes to intentionally switch from one pattern to another depends on the differential stability of the patterns themselves; and (b) that an intention, defined as an intended behavioral pattern, can change the dynamical characteristics, e.g., the overall stability of the behavioral patterns. Subjects moved both index fingers rhythmically at one of six movement frequencies while performing either an in-phase or antiphase pattern of finger coordination. On cue from an auditory signal, subjects switched from the ongoing pattern to the other pattern. The relative phase of movement between the two fingers was used to characterize the ongoing coordinative pattern. The time taken to switch between patterns, or switching time, and relative phase fluctuations were used to evaluate the modified pattern dynamics resulting from a subject's intention to change patterns. Switching from the in-phase to the antiphase pattern was significantly slower than switching in the opposite direction for all subjects. Both the mean and distribution of switching times in each direction were found to be in agreement with model predictions. Movement frequency had little effect on switching time, a finding that is also consistent with the model. Relative phase fluctuations were significantly larger when moving in the antiphase pattern at the highest movement frequencies studied. The results show that, although intentional influences act to modify a coordinative pattern's intrinsic dynamics, the influence of these dynamics on the resulting behavior is always present and is particularly strong at high movement frequencies.     

Male Physical Attractiveness as a Potential Contaminating Variable in Ratings of Heterosocial Skill

Abstract

Behavioral and self-report measures of intrinsic task interest of American university students were compared in relation to momentary mood, long-term motivational orientation, and interest in competing activities. Although the two measures of intrinsic motivation were significantly correlated, significant contrasts were found in their correlations with other factors. Results support an earlier proposal that the behavioral (free-choice time) measure depends on how treatments affect interest in alternative activities, not just interest in the target activity. A model of how the two measures differ is outlined.     

Patterns of Silent Reading Rate and Comprehension as a Function of Developmental Status,Genre, and Text Position

This study examined how comprehension-based silent reading rate (CBSRR) is affected by grade, genre, and text position. Second and fourth graders read 2 grade-specific passages (one narrative, one informational) in 4 sections, each followed by 4 comprehension questions. Analyses of rate with a criterion level of comprehension showed higher performances on informational than narrative texts and better performances as students moved through sections of a text. Percentages of students attaining CBSRR decreased across the four sections of both genres and at both grade levels. Implications of findings are discussed and question are raised about text complexity and silent reading patterns.