A theoretical note on models of interlimb coordination.

This article clarifies some points about models of interlimb coordination. The authors discuss in detail the predictions and extensions of the H. Haken et al (1985) model and compare these to a truncated version used by R. C. Schmidt and colleagues. It is demonstrated that procedures commonly used to fit experimental data to model parameters require the fulfillment of certain assumptions. Finally, the authors show how recent experimental findings can be modeled straightforwardly using a system of coupled nonlinear oscillators. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Central generation of grooming motor patterns and interlimb coordination in locusts

Coordinated bursts of leg motoneuron activity were evoked in locusts with deefferented legs by tactile stimulation of sites that evoke grooming behavior. This suggests that insect thoracic ganglia contain central pattern generators for directed leg movements. Motoneuron recordings were made from metathoracic and mesothoracic nerves, after eliminating all leg motor innervation, as well as all input from the brain, subesophageal ganglion, and prothoracic ganglion. Strong, brief trochanteral levator motoneuron bursts occurred, together with silence of the slow and fast trochanteral depressor motoneurons and activation of the common inhibitor motoneuron. The metathoracic slow tibial extensor motoneuron was active in a pattern distinct from its activity during walking or during rhythms evoked by the muscarinic agonist pilocarpine. Preparations in which the metathoracic ganglion was isolated from all other ganglia could still produce fictive motor patterns in response to tactile stimulation of metathoracic locations. Bursts of trochanteral levator and depressor motoneurons were clearly coordinated between the left and right metathoracic hemiganglia and also between the mesothoracic and the ipsilateral metathoracic ganglia. These data provide clear evidence for centrally generated interlimb coordination in an insect.     

Dissociation of muscular and spatial constraints on patterns of interlimb coordination.

Interlimb coordination is subject to constraints. One major constraint has been described as a tendency for homologous muscle groups to be activated simultaneously. Another has been described as a biasing of limb segments to movement in the same direction. In 2 experiments, the 2 constraints were placed in opposition: In-phase or antiphase contraction of homologous muscles of contralateral limbs produced movement that was spatially antiphase or in-phase, respectively. Probability distributions of relative phase were obtained under manipulations of phase detuning and movement speed. They revealed that the equilibrium and stability of coordination were related, respectively, to spatial relative phase and muscular relative phase. Previously observed spatial and muscular constraints reflect a (possibly very general) factorization of attractor location and attractor strength in the dynamics of interlimb coordination. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Distinguishing between the effects of frequency and amplitude on interlimb coupling in tapping a 2:3 polyrhythm

Rhythmic interlimb coordination is characterized by attraction to stable phase and frequency relations. Sudden, unintended transitions between such coordination patterns have been observed in iso- and multifrequency tasks when movement frequency was gradually increased. These transitions have been accounted for by modeling the two limbs as nonlinearly coupled oscillators. The prevailing form of the coupling function is based on time derivatives, but an alternative formulation can be derived by incorporating time delays. These time delays may be related to the neurophysiological delays associated with the use of kinesthetic afferences. The two ways of deriving coupling functions for interlimb coordination allow for different predictions with respect to the effects of movement frequency and amplitude on the strength of interaction between the limbs. In the current experiment, the effects of amplitude and frequency were dissociated experimentally, so as to arrive at an empirically motivated choice between the two ways of formalizing interlimb coupling. Subjects tapped the polyrhythm 2:3 at five different frequencies under three amplitude conditions. Whereas no effects of amplitude were observed, the strength of interaction between the hands decreased with increasing movement frequency. These results support the time-delay version of the model, in which differential (loss of) stability of coordination modes results from differential dependence on movement amplitude, but overall coupling strength is related reciprocally to movement frequency squared. This version of the model was related tentatively to three proposed aspects of interlimb coordination: (1) neurophysiological delays associated with the use of kinesthetic afferences; (2) rate-dependent decrease in pattern stability; and (3) differential entrainment influences of kinesthetic signals.     

Models of interlimb coordination—Equilibria, local analyses, and spectral patterning: Comment on Fuchs and Kelso (1994).

This article is a comment on A. Fuchs and J. A. S. Kelso's (see record 1995-08247-001) theoretical note on models of interlimb coordination. The generality of the order parameter equation derived by H. Haken, J. A. S. Kelso, and H. Bunz ([HKB] 1985) for correlated limb movements is underscored through the correct and nonintuitive predictions it makes about steady state behavior. Local and global dynamical models are contrasted, and experimental situations in which local models are pragmatic alternatives to global models, like the HKB equation, are described. Questions are raised about the basis for interpreting detuning in HKB as a simple frequency difference and about the ability of the system of coupled nonlinear oscillators proposed by A. Fuchs and J. A. S. Kelso to model fully the experimental findings on the spectrum of relative phase. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Do interpersonal traits predict affect? A comparison of three models.

Predictions from interpersonal traits to affect were examined in the context of 3 models. In the global trait model, traits were used to predict affect aggregated over a 20-day period. In the situational congruence model, traits were used to predict affect in trait-relevant situations. In the behavioral concordance model, the co-occurrence between behaviors and affect was examined for individual participants, and then traits were used to predict the degree to which behavior and affect co-occurred. No support was found for the global trait and situational congruence models. Support was found for the behavioral concordance model for 3 of the 4 traits. Individuals high on agreeableness and quarrelsomeness experienced pleasant affect when they engaged in behaviors concordant with their traits. Individuals high on agreeableness, quarrelsomeness, and dominance experienced unpleasant affect when they engaged in behaviors opposite to their traits. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multifrequency coordination in bimanual tapping: Asymmetrical coupling and signs of supercriticality.

The circle map provides a general mathematical model for the mode-locking behavior observed in systems of coupled oscillators. From this theoretical perspective, multifrequency tapping was studied. Three experiments were conducted in which skilled drummers participated. The results were in qualitative agreement with the dynamical features of the circle map. The stability of behavior was affected by the movement frequency at which the multifrequency relations were performed. Attraction to lower order ratios (predominantly showing Farey relations) was observed. In some situations bistability and hysteresis occurred, implying that the system was situated in the supercritical domain of the circle map where resonance zones overlap. Furthermore, the results suggest that multifrequency tapping is characterized by an asymmetrical coupling in that the influence of the fast hand on the slow hand is the strongest. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Harming high performers: A social comparison perspective on interpersonal harming in work teams.

This study developed a multilevel model of the interpersonal harming behavior associated with social comparison processes in work teams. We tested this model using temporally lagged data from a sample of student teams (Study 1) and cross-sectional data from a sample of work teams in a telecommunication services company (Study 2). In both studies, social relations analyses revealed that in teams with less cooperative goals, comparison to a higher performing team member was positively associated with interpersonal harming behavior, but only when expectations of future performance similarity to that member were low. The interactive relationship of social comparison and expected future performance similarity with interpersonal harming was buffered, however, in teams with more cooperative goals. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Spatial coupling in the coordination of complex actions

The majority of investigations on coordinated action have focused on temporal constraints in movements. Recent studies have demonstrated spatial constraints when the hands produce different trajectory shapes simultaneously. The focus of the current study was to determine whether spatial coupling occurs in individual parameters of the actions, or whether the shapes per se undergo accommodation. Subjects were tested on a bimanual paradigm to investigate the nature of spatial constraints in complex tasks. Shape and size of the required trajectories were varied for two limbs. When trajectories that require different shapes were assigned to the two hands, disruption in the spatial characteristics of the trajectories was observed. Disruption in the global patterns of the trajectories could be described on the basis of coupling in individual parameters of action, direction, and amplitude, which could be inferred by decomposing the trajectories into orthogonal components. Amplitude accommodation in these orthogonal components of motion increased linearly with the difference in required amplitude for the two limbs. Interpretations of these effects suggest that directional coupling is a result of interference between two different response plans, whereas amplitude coupling may be related to either planning or execution variables. These results strongly suggest the need for further investigation of the spatial domain of complex coordinated action.     

Group cognitive-behavioral therapy and group interpersonal psychotherapy for the nonpurging bulimic individual: A controlled comparison.

Evaluated the effectiveness of group cognitive-behavioral treatment (CBT) and group interpersonal psychotherapy (IPT) for binge eating. 56 women with nonpurging bulimia were randomly assigned to 1 of 3 groups: CBT, IPT, or a wait-list control (WLC). Treatment was administered in small groups that met for 16 weekly sessions. At posttreatment, both group CBT and group IPT treatment conditions showed significant improvement in reducing binge eating, whereas the WLC condition did not. Binge eating remained significantly below baseline levels for both treatment conditions at 6-mo and 1-yr follow-ups. These data support the central role of both eating behavior and interpersonal factors in the understanding and treatment of bulimia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Environmental coupling modulates the attractors of rhythmic coordination.

A simple instance of coupling behavior to the environment is oscillating the hands in pace with metronome beats. This environmental coupling can be weaker (1 beat per cycle) or stronger (2 beats per cycle). The authors examined whether strength of environmental coupling enhanced the stability of in-phase bimanual coordination. Detuning by manipulanda that produced different left and right eigenfrequencies shifted the relative phase angle from 0°, with the size of the shift larger for higher movement frequencies. Stronger environmental coupling was found to decrease this relative-phase shift, with accompanying increase and reduction, respectively, in recurrence quantification measures related to coordination stability and coordination noise. Stronger environmental coupling also increased oscillation amplitude. Results are considered from the perspective of parametric stabilization. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Self-evaluation effects of interpersonal versus intergroup social comparison.

Two studies tested the prediction that the outcome of social comparison will differ depending on whether interpersonal or intergroup comparison processes have been engaged. Results of an experiment in which college students were assigned to membership in a minority or majority social category confirmed the predicted 3-way interaction effect of in-group salience, target group membership, and upward–downward comparison on self-assessments of academic ability. Majority group members exhibited contrast effects in their self-ratings following exposure to a videotape of an in-group member displaying either very high or very low academic competence. Self-evaluations of minority group members revealed assimilation effects in response to in-group comparisons and contrast effects in response to out-group comparisons. In a 2nd follow-up experiment, this in-group assimilation effect was found to be dependent on intergroup contrast. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bulimia and interpersonal relationships: A longitudinal study.

We assessed changes in bulimia in female college students and changes in the relation between bulimia and interpersonal relationships with women and men. A measure of bulimia (BULIT) of M. C. Smith and M. H. Thelen (see record 1985-02946-001) was taken at Time 1, after a 7-month interval (Time 2), and again after a 12-month interval (Time 3). Measures of interpersonal relationships with women and men were taken at Time 2 and Time 3. Three groups were constituted on the basis of BULIT scores at Time 1: bulimic, subclinical bulimic (Ss who tested just under the cutoff for bulimia), and normal. Ss who tested bulimic or normal at Time 1 tended to continue to do so. In contrast, the subclinical bulimic group endorsed less bulimic symptomatology over time. There were strong negative correlations between the BULIT and ratings of interpersonal relationships with men. The subclinical bulimics showed the greatest improvement over time in ratings of their relationships with men. Counselors may need to consider severity of bulimia and relationship issues during treatment planning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Predicting preschoolers' peer behavior and status from their interpersonal strategies: A comparison of verbal and enactive responses to hypothetical social dilemmas.

The purposes of this study were (a) to compare a verbal and an enactive procedure for assessing preschool children's social strategies in hypothetical situations in terms of their ability to predict social behavior with peers and peer acceptance and (b) to examine some of the psychometric properties of the two assessment methods. Children's responses to a set of hypothetical social situations were elicited both with puppets and props (enactive assessment) and with a set of pictures (verbal assessment). The responses were rated in terms of their friendliness and assertiveness. Enactive friendliness ratings contributed significantly to regression equations predicting teacher and observer ratings of prosocial and aggressive behavior but not to peer group acceptance, whereas the verbal method contributed little predictive power beyond that provided by the enactive ratings. Implications for social skill assessment and intervention with children are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Let the force be with us: Dyads exploit haptic coupling for coordination.

People often perform actions that involve a direct physical coupling with another person, such as when moving furniture together. Here, we examined how people successfully coordinate such actions with others. We tested the hypothesis that dyads amplify their forces to create haptic information to coordinate. Participants moved a pole (resembling a pendulum) back and forth between two targets at different amplitudes and frequencies. They did so by pulling on cords attached to the base of the pole, one on each side. In the individual condition, one participant performed this task bimanually, and in the joint condition two participants each controlled one cord. We measured the moment-to-moment pulling forces on each cord and the pole kinematics to determine how well individuals and dyads performed. Results indicated that dyads produced much more overlapping forces than individuals, especially for tasks with higher coordination requirements. Thus, the results suggest that dyads amplify their forces to generate a haptic information channel. This likely reflects a general coordination principle in haptic joint action, where force amplification allows dyads to perform at the same level as individuals. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Bilateral reaching to asymmetrical targets: muscle and joint dynamic interlimb adaptations

Treatment of acute embolic and thrombotic occlusions of arteries has to be initiated immediately to save the limb at risk. Surgery has been the treatment of choice for the last decades. Percutaneous mechanical methods for thrombectomy and thrombolysis have evolved and offer alternative treatment options, reducing the peri-operative risk. Percutaneous aspiration thrombembolectomy (PAT), recirculation thrombectomy with the Amplatz device, and different systems for hydrodynamic thrombectomy and thrombolysis (Angiojet, Hydrolyer, S.E.T. catheter) are routinely used for percutaneous thrombectomy and mechanical thrombolysis. These 3.5-10 F systems allow for the rapid removal of a fresh clot from different vascular regions. Complete removal of the clot can be achieved in 19-49%; adjunctive use of other percutaneous methods (thrombolysis and thrombectomy: 60-80%; PTA and atherectomy: 81-100%) results in primary success rates of 67-100% for recanalization of acutely occluded vessels. Primary indications for percutaneous thrombectomy and mechanical thrombolysis are acute occlusions of peripheral arteries and dialysis fistulas; limited experience exists for the treatment of occlusions of the visceral and pelvic vessels. Percutaneous methods seem promising for treatment of acute pulmonary embolism.     

Associative strength as a mode of organization in recall and recognition: A comparison of schizophrenics and normals.

In 2 experiments, word pairs of high and low intrapair association were presented to a total of 40 schizophrenic and 40 normal adults. In Exp I, 1 member of each pair in both recall and recognition tasks was also displayed as a cue at the time of response. The number of words correctly recalled and recognized by both schizophrenics and normals was markedly greater for high-association lists. On high-association lists, schizophrenic performance was inferior to that of normals. The same lists were used in Exp II, which required the recognition of both words in each pair. Normal recognition was superior only for high-association lists. Results are interpreted as supporting the view that because schizophrenics did not subjectively organize or encode information when presented, subsequent retrieval was deficient. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Functional flexibility: A new conception of interpersonal flexibility.

Traditional conceptions of interpersonal flexibility emphasize two critical components: (a) a wide range of interpersonal responses and (b) situational appropriateness. Most current measures are based on standard trait ratings, which cannot address situational adjustment. In place of trait ratings, we suggest the use of capability ratings, that is, self-reports of the ease of performing social behaviors when required by the situation. Our proposed index of flexibility, the Functional Flexibility Index (FFI), is the composite of 16 interpersonal capabilities. In Study 1, factor analyses indicated that the FFI is distinct from other widely used flexibility measures. Study 2 supported the validity of the FFI by showing substantial correlations with peer ratings of interpersonal flexibility. In Studies 3 and 4, the FFI outperformed other flexibility measures in predicting adjustment. Another form of interpersonal variability, situationality, is the tendency to view one's personality as being dependent on the situation. Situational individuals reported lower self-esteem than nonsituational individuals. Measures of functional flexibility and situationality were found to be orthogonal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)