Patterns of Human Interlimb Coordination Emerge from the Properties of Non-Linear,Limit Cycle Oscillatory Processes

The present article represents an initial attempt to offer a principled solution to a fundamental problem of movement identified by Bernstein (1967), namely, how the degrees of freedom of the motor system are regulated. Conventional views of movement control focus on motor programs or closed-loop devices and have little or nothing to say on this matter. As an appropriate conceptual framework we offer Iberall and his colleagues’ physical theory of homeokinetics first elaborated for movement by Kugler, Kelso, and Turvey (1980). Homeokinetic theory characterizes biological systems as ensembles of non-linear, limit cycle oscillatory processes coupled and mutually entrained at all levels of organization. Patterns of interlimb coordination may be predicted from the properties of non-linear, limit cycle oscillators. In a set of experiments and formal demonstrations we show that cyclical, two-handed movements maintain fixed amplitude and frequency (a stable limit cycle organization) under the following conditions: (a) when brief and constantly applied load perturbations are imposed on one hand or the other, (b) regardless of the presence or absence of fixed mechanical constraints, and (c) in the face of a range of external driving frequencies from a visual source. In addition, we observe a tight phasic relationship between the hands before and after perturbations (quantified by cross-correlation techniques), a tendency of one limb to entrain the other (mutual entrainment) and that limbs cycling at different frequencies reveal non-arbitrary, sub-harmonic relationships (small integer, subharmonic entrainment). In short, all the above patterns of interlimb coordination fall out of a non-linear oscillatory design. Discussion focuses on the compatibility of these results with past and present neurobiological work, and the theoretical insights into problems of movement offered by homeokinetic physics. Among these are, we think, the beginnings of a principled solution to the degrees of freedom problem, and the tentative claim that coordination and control are emergent consequences of dynamical interactions among non-linear, limit cycle oscillatory processes.     

The Relationship Between Blood Lead,Bone Lead and Child Intelligence

We report associations between serial measures of blood lead and intelligence in children age 10–12 years, half heavily exposed to lead from the prenatal period onward, and half relatively unexposed. For a subsample, we examine bone lead-IQ associations, comparing them with blood lead associations. Both blood and bone lead levels were associated with intelligence decrements, small relative to the contribution of social factors. For each doubling of Tib-Pb, Full Scale, Performance, and Verbal IQ decreased by an estimated 5.5, 6.2, and 4.1 points, respectively. Bone lead-IQ associations were stronger than those for blood lead, which nonetheless provide robust analogues. Current BPb, easy to obtain, provides a useful means for assessing Pb exposure/IQ associations.     

The relationship between blood lead, bone lead and child intelligence.

We report associations between serial measures of blood lead and intelligence in children age 10-12 years, half heavily exposed to lead from the prenatal period onward, and half relatively unexposed. For a subsample, we examine bone lead-IQ associations, comparing them with bone lead associations. Both blood and bone lead levels were associated with intelligence decrements, small relative to the contribution of social factors. For each doubling of Tib-Pb, Full Scale, Performance, and Verbal IQ decreased by an estimated 5.5, 6.2, and 4.1 points, respectively. Bone lead-IQ associations were stronger than those for blood lead, which nonetheless provide robust analogues. Current BPb, easy to obtain, provides a useful means for assessing Pb exposure/IQ associations.     

The Protestant Work Ethic,Expectancy Violations,and Criminal Sentencing1

To test the hypothesis that endorsement of the Protestant work ethic would be related positively to sensitivity to criminal behavior that violated expectations, American college students (N = 159) read scenarios describing a crime committed by a typical or an atypical offender. After answering questions about the crime, they completed Mirels and Garrett's (1971) Protestant Work Ethic (PWE) scale. Extent of punishment was positively related to PWE for atypical criminal behavior. Yet, high PWEs also were more likely to perceive an affluent criminal as experiencing greater remorse for a blue‐collar crime than a white‐collar crime. We relate our results to perceptions of criminal behavior, information‐processing tendencies among individuals endorsing the PWE, and jury selection considerations.     

The relation of self-reported competencies to aptitude test scores

The scales of the Self-Directed Search were correlated with the scales of the Armed Forces Vocational Aptitude Battery for a sample of 192 high school girls. The two devices have small to moderate correlations that indicate that self-reported abilities and competencies have some concurrent validity.     

On the space-time structure of human interlimb co-ordination

In three experiments we show, using behavioural measures of movement outcome, as well as movement trajectory information and resultant kinematic profiles, that there is a strong tendency for the limbs to be co-ordinated as a unitary structure even under conditions where the movements are of disparate difficulty. Environmental constraints (an obstacle placed in the path of one limb, but not in the other) are shown to modulate the space-time behaviour of both limbs (Experiment II). Our results obtain for symmetrical (Experiment I) as well as asymmetrical movements that involve non-homologous muscle groups (Experiment III). These findings suggest that in multi-joint limb movements, the many degrees of freedom are organised to function temporarily as a single coherent unit that is uniquely specific to the task demands placed on it. For movements in general, and two-handed movements in particular, such units are revealed in a partitioning of the relevant force demands for each component (a force scaling characteristic) and a preservation of the internal “topology” of the action, as indexed by the relative timing among components. These features, as well as systematic deviations from perfect synchrony between the limbs can be rationalised by a model that assumes the limbs behave qualitatively like non-linear oscillators.     

Can Messages Make a Difference? The Association Between E‐Mail Messages and Health Outcomes in Diabetes Patients

This investigation examined the impact of social support messages on patient health outcomes. Forty‐one American Indian, Alaska Native, and Native Hawaiian patients received a total of 618 e‐mail messages from their healthcare provider (HCP). The e‐mail messages were divided into 3,565 message units and coded for instances of emotional social support. Patient glycosulated hemoglobin scores (HbA1c) showed significantly improved glycemic control and emotional social support messages were associated with significant decreases in HbA1c values. Patient involvement with the system, measured by system login frequency and the frequency of uploaded blood glucose scores to the HCP, did not predict change in HbA1c.     

Writing the (researcher) self: reflective practice and undergraduate research

This paper discusses the way in which postmodern emergence was used to assist a group of undergraduate students come to new understandings of research practice as they participated in a reflective component of an Undergraduate Research Summer School. Students were encouraged to ‘write the (researcher) self’ through a collaborative writing group based on the theoretical and pedagogical work of Somerville. Postmodern emergence highlights three stages of learning; firstly, assigning time for wondering, then a liminal space for becoming and finally an opportunity for generating new knowledge. This article is both the tangible product of this emergence reflective writing process and a recommendation about the capacity of undergraduate students to engage with their own professionalisation and meaning-making.     

First‐time mothers in home visitation services utilizing child development specialists

Professionals in the field of child development were employed to provide home visitation services to 156 mothers and infants prenatally through the infants' first birthdays. Compared to a control group of mothers (n = 107), the intervention mothers utilized more community resources, had safer homes, had more appropriate developmental expectations, had better understanding of noncorporal punishment, and had behaviors that were more accepting and respectful to their infants. The home visitors were well educated, with experience in home visitation, and supervised. Program implementation procedures were documented and supervised. Program fidelity and the efficacy of using child development specialists as home visitors are discussed in regards to the positive findings. ©2004 Michigan Association for Infant Mental Health.     

Foucault and the Glamazon: The Autonomy of Ronda Rousey

In this paper, we examine the case of Ronda Rousey, a high profile female Mixed Martial Arts (MMA) fighter in the Ultimate Fighting Championship (UFC). We argue that Rousey represents a female athlete who can be considered a gender transgressor yet simultaneously a Glamazon. The case of Rousey will be applied to gender transgressor theories to demonstrate that Rousey counters traditional discourse which holds that exhibiting stereotypically masculine traits implies not being an authentic woman. Female fighters face criticisms for being “unfeminine” or “manly” because they participate in such an aggressive sport. Despite her gender divergent behaviour, as much as she transgresses, Rousey is also pinned by sporting and societal sexist culture that reinforces sex binaries and exposes pressures to adhere to hyperfemininity and heterosexual ideals. Finally, using the notions of self and power found in Michel Foucault’s later work as a springboard, we examine whether Rousey’s embrace of the Glamazon identity is an act of autonomy or evidence of false consciousness.