Dynamics of 1:2 Coordination: Temporal Scaling,Latent 1:1, and Bistability

The simplest interlimb multifrequency coordination of 1:2 can be performed at different speeds and in at least two different styles or modes. The effects of speed and mode (in-phase or antiphase) were evaluated in a bimanual 1:2 rhythmic task in which participants (N = 8) oscillated hand-held pendulums with identical or different uncoupled frequencies. A motion equation in relative phase that captures the asymmetries of components and task predicted the 1:2 coordination equilibria resulting from temporal scaling. According to the experimental results, both coordination modes proved to be equally stable. More detailed analyses of individual trials showed signs that the more fundamental 1:1 coordination intruded into the 1:2 coordination.     

Dynamics of 1:2 Coordination: Temporal Scaling, Latent 1:1, and Bistability

The simplest interlimb multifrequency coordination of 1:2 can be performed at different speeds and in at least two different styles or modes. The effects of speed and mode (in-phase or antiphase) were evaluated in a bimanual 1:2 rhythmic task in which participants (N = 8) oscillated hand-held pendulums with identical or different uncoupled frequencies. A motion equation in relative phase that captures the asymmetries of components and task predicted the 1:2 coordination equilibria resulting from temporal scaling. According to the experimental results, both coordination modes proved to be equally stable. More detailed analyses of individual trials showed signs that the more fundamental 1:1 coordination intruded into the 1:2 coordination.     

Dynamics of 1:2 Coordination: Generalizing Relative Phase to n:m Rhythms

Interlimb rhythmic movements can be modeled as coupled oscillators, with stable performance characterized by the relative phase between the limbs. In the present study, that modeling strategy, verified previously for 1:1 coordination, was generalized to 1:2 coordination with a view to n:m coordination. The generalized model predicted interactions between coordination (specifically, 1:1 vs. 1:2) and the frequency asymmetry between the limbs determining mean relative phase and its variability. The predicted interactions were evaluated with bimanual 1:2 and 1:1 rhythmic tasks in which participants (N = 8) oscillated hand-held pendulums whose uncoupled frequencies could be adjusted so that different interlimb asymmetries were produced. The authors needed new analytic procedures to verify stable 1:2 coordination and to resolve stochastic and deterministic sources of variability in the component oscillations. The major expectations from the generalized model were confirmed, and the implications of additional but unpredicted findings for the modeling of multifrequency behavior are discussed.     

Dynamics of expertise level: Coordination in handstand

The aim of the present study was to investigate the effect of expertise on coordination patterns. We thus tested the coordination dynamics of two groups: experts in the handstand also having high expertise in gymnastics and experts in the handstand but only intermediate expertise in gymnastics. All participants were instructed to track a target with their ankles while maintaining the handstand. The target moved on the anterior-posterior axis according to three frequency conditions: 0.2, 0.4 and 0.6 Hz. The results showed that the suprapostural task was performed better by the group with high gymnastics expertise. Moreover, the spontaneous coordination was specific to the level of gymnastics expertise. We concluded that (i) the dynamics of coordination progress with the overall level of expertise in a sport discipline, independently of the mastery of a single skill, (ii) persistence and change are seen in related movement properties, and (iii) high expertise offers greater adaptability relative to the task.     

Coordination Dynamics of the Horse-Rider System

The authors studied the interaction between rider and horse by measuring their ensemble motions in a trot sequence, comparing 1 expert and 1 novice rider. Whereas the novice's movements displayed transient departures from phase synchrony, the expert's motions were continuously phase-matched with those of the horse. The tight ensemble synchrony between the expert and the horse was accompanied by an increase in the temporal regularity of the oscillations of the trunk of the horse. Observed differences between expert and novice riders indicated that phase synchronization is by no means perfect but requires extended practice. Points of contact between horse and rider may haptically convey effective communication between them.     

Coordination Dynamics of the Bipedal Galloping Pattern

A motion equation in relative phase was developed that incorporates the spatial-temporal pattern of the bipedal gallop along with the more commonplace patterns of the bipedal jump and walk-run. In 3 experiments, human participants (N = 6 per experiment) simulated the bipedal gait patterns through the rhythmic motions of hand-held pendulums. Predictions of the motion equation for coordination equilibria and their respective degrees of stability were confirmed. In particular, the gallop pattern was less stable than the fundamental in-phase and antiphase patterns but changed in qualitatively similar ways to those gaits as a function of limb asymmetry and movement frequency. The relation between the modeled coordination dynamics and the kinematic characteristics of real bipedal galloping is discussed     

Coordination Dynamics of the Bipedal Galloping Pattern

A motion equation in relative phase was developed that incorporates the spatial-temporal pattern of the bipedal gallop along with the more commonplace patterns of the bipedal jump and walk-run. In 3 experiments, human participants (N = 6 per experiment) simulated the bipedal gait patterns through the rhythmic motions of hand-held pendulums. Predictions of the motion equation for coordination equilibria and their respective degrees of stability were confirmed. In particular, the gallop pattern was less stable than the fundamental in-phase and antiphase patterns but changed in qualitatively similar ways to those gaits as a function of limb asymmetry and movement frequency. The relation between the modeled coordination dynamics and the kinematic characteristics of real bipedal galloping is discussed.     

Leg Asymmetries and Coordination Dynamics in Walking

Models of interlimb coordination (H. Haken, J. A. S. Kelso, &; H. Bunz, 1985 Haken, H., Kelso, J. A. S. and Bunz, H. 1985. A theoretical model of phase transitions in human hand movements. Biological Cybernetics, 51: 347–356. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; P. N. Kugler &; M. T. Turvey, 1987 Kugler, P. N. and Turvey, M. T. 1987. Information, natural law, and the self-assembly of rhythmic movement, Hillsdale, NJ: Erlbaum.  [Google Scholar]) were tested in walking by examining the role of asymmetries between limbs. Participants walked on a treadmill with and without a metronome. Five asymmetry conditions were created via ankle loads of 0, 3, or 6 kg on either leg. With the metronome, participants matched the target period. Without the metronome, stride rate slowed as the mass was increased on either leg. The loads led to an increase in stride period that was predicted by Huygens’ law and the hybrid pendulum-spring model. In agreement with extended Haken–Kelso–Bunz model predictions, leg asymmetries led to deviations from antiphase coordination. Also, perception–action coordination was influenced by the asymmetry between the legs and metronome. In contrast, no predicted stability effects were observed. These findings reveal that some properties of interlimb coordination, apparent in laboratory-based tasks, can also be observed in human walking.     

Sources of Perceived Organizational Support: Goal Setting and Feedback1

In this paper we examine goal setting and feedback as possible sources of perceived organizational support (Eisenberger, Huntington, Hutchison, & Sowa, 1986). Surveys were administered to 337 employees from 3 different organizations in the southern California area. Two path models were examined: one that allowed goal setting and feedback to have direct effects on perceived support and organizational commitment, and one that only allowed goal setting and feedback to have direct effects on perceived support. Results show that goal setting and feedback do not have direct effects on organizational commitment but, rather, affect commitment indirectly by way of their effects on employee perceptions of support from the organization.     

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.     

Sources of Resistance to Mergers Between Groups1

Workers involved in a business merger often display strong ingroup/outgroup biases that can threaten the merger's success. Social identity theory helps to explain why and when such problems will occur. Using that theory, strong cohesion and successful performance were identified as two characteristics of a workgroup that should increase its resistance to a merger. An experiment involving mergers between small task groups was conducted to test this claim. Each group's cohesion and performance was used to predict its enthusiasm for a merger before it occurred, and any ingroup/outgroup biases that it displayed afterwards. Cohesion was unrelated to either of these measures, but as we predicted, more successful groups were less enthusiastic and displayed stronger biases. Relative rather than absolute success was an especially good predictor of merger resistance. The results were discussed within the context of social identity theory, which generated several suggestions for further research on business mergers.     

A Place to Heal: Environmental Sources of Satisfaction Among Hospital Patients1

Telephone interviews with 380 discharged inpatients were conducted to identify environmental sources of satisfaction with the hospital, to determine the relative contribution of environmental satisfaction to overall satisfaction with the hospital experience, and to explore differences in satisfaction across 4 departments (medical, obstetrics, orthopedics, and surgical) and 6 hospitals. Analyses indicate that interior design, architecture, housekeeping, privacy, and the ambient environment were all perceived as sources of satisfaction. Environmental satisfaction was a significant predictor of overall satisfaction, ranking below perceived quality of nursing and clinical care. There were no significant differences between hospitals or departments in the level or sources of environmental satisfaction. Results suggest potential directions for architects, designers, and health care providers.     

Mass Perturbation of a Body Segment: 2. Effects on Interlimb Coordination

The shifts in relative phase that are observed when rhythmically coordinated limbs are submitted to asymmetric mass perturbations have typically been attributed to the induced eigenfrequency difference ($DL$oM) between the limbs. Modeling the moving limbs as forced linear oscillators, however, reveals that asymmetric mass perturbations may induce a difference not only in eigenfrequency (i.e., $DL$oM $$ 0) but also in the covarying low-frequency control gains (i.e., $DLk $$ 0). Because the inverse of the lowfrequency control gain (k) reflects the level of muscular torque (input) required for a particular displacement from equilibrium (output), asymmetric mass perturbations may result in an imbalance in the muscular torques required for task performance (related to $DLk $$ 0). Thus, it is possible that the effects attributed to $DL$oM were in fact mediated by $DLk. In 2 experiments, the authors manipulated $DLk and $DL$oM separately by applying mass perturbations to the lower legs of 9 participants. The relative phasing between the legs was not affected by $DLk, but manipulation of $DL$oM (while $DLk remained approximately 0) induced systematic relative phase shifts that were more pronounced for antiphase than for in-phase coordination. That indication that the coordination dynamics is indeed influenced by an imbalance in eigenfrequency is discussed vis-à-vis the question of how such a merely peripheral property may affect the underlying coordination process.     

Christian Privilege: Breaking a Sacred Taboo

The author discusses the concept of privilege in terms of the benefits enjoyed by Whites and men (P. McIntosh, 1998). This article presents a new theoretical perspective focusing on religious privilege and includes a list of privileges that are enjoyed by members of the dominant religious group (i.e., Christians) in the United States. El autor discute el concepto del privilegio en cuanto a los beneficios que disfrutan los Blancos y los hombres (P. McIntosh, 1998). Este artículo presenta una nueva perspectiva teorética que enfoca al privilegio religioso e incluye una lista de privilegios que disfrutan miembros del grupo religioso dominante de los Estados Unidos, los cristianos.     

Psychopaths and Symmetry: A Reply to Nelkin

Philosophia - An agent is morally competent if she can respond to moral considerations. There is a debate about whether agents are open to moral blame only if they are morally competent, and Dana...     

Beyond Beauty: Design Symmetry and Brand Personality

Our research explores connections between a fundamental element of visual design, namely symmetry, and consumer inferences regarding brand personality. In contrast to prior work focused on broad affective responses, we propose that symmetry plays an additional, nuanced role in the communication of brand personality. Results of four experiments reveal that asymmetry in visual brand elements is associated by consumers with brand excitement, and that the effect is driven in part by the experience of subjective arousal. These findings contribute to growing interest in visual design and consumer processing, while extending current understanding regarding the communication of brand personality.     

Spontaneous Interpersonal Coordination in Stepping and Autistic-Like Traits1

Spontaneous behavior, matching that of others, is influenced by various social factors. Mimicking and synchronizing with others' behaviors can facilitate the development of harmonious relationships. This study examined whether the level of autistic-like traits in a non-clinical population influences the spontaneous-behavioral coordination of a dyad's stepping-on-the-spot movements. The strength of spontaneous stepping synchronization was negatively correlated with levels of autistic-like traits when participants faced one another, and no synchronization was observed for individuals with high levels of autistic-like traits. The deficit in spontaneous interpersonal behaviour-matching among individuals with high levels of autistic-like traits is discussed as a potential source of their poor social-communication abilities.