Advantages of Rhythmic Movements at Resonance: Minimal Active Degrees of Freedom,Minimal Noise,and Maximal Predictability

Using time delay embedding, the authors applied phase space reconstruction to the time series of rhythmic movements of a hand-held pendulum. Subjects (N = 6) produced the manual oscillations about the wrist at the pendulum's resonant frequency and at a higher and a lower frequency. The number of active degrees of freedom required to capture the dynamics of the rhythmic behavior was 3 for the resonant frequency and 4 for each of the nonresonant frequencies. The residual high-dimensional noise was similarly lowest for the resonant frequency. Whereas 33% and 20%, respectively, of the vectors in the phase spaces of the dynamics higher and lower than resonance were unpredictable, only 12% were unpredictable at resonance. Finally, the predictability of the evolving dynamics extended farther into the future for oscillations at the resonant frequency. At resonance, the prediction horizon was 5 times farther than the prediction horizon for the higher than resonance behavior and 2.5 times farther than that for the lower than resonance behavior. The results suggest that, in pendular oscillations of a limb or limb segment, attunement of the central nervous system to the resonant frequency minimizes the variables to be controlled and maximizes the predictability of the rhythmic movement's chaotic dynamics.     

Plane of Motion Mediates the Coalition of Constraints in Rhythmic Bimanual Coordination

The authors hypothesized that the modulation of coordinative stability and accuracy caused by the coalition of egocentric (neuromuscular) and allocentric (directional) constraints varies depending on the plane of motion in which coordination patterns are performed. Participants (N = 7) produced rhythmic bimanual movements of the hands in the sagittal plane (i.e., up-and-down oscillations resulting from flexion—extension of their wrists). The timing of activation of muscle groups, direction of movements, visual feedback, and across-trial movement frequency were manipulated. Results showed that both the egocentric and the allocentric constraints modulated pattern stability and accuracy. However, the allocentric constraint played a dominant role over the egocentric. The removal of vision only slightly destabilized movements, regardless of the effects of directional and (neuro)muscular constraints. The results of the present study hint at considering the plane in which coordination is performed as a mediator of the coalition of egocentric and allocentric constraints that modulates coordinative stability of rhythmic bimanual coordination.     

Discovery of the Pendulum and Spring Dynamics in the Early Stages of Walking

The authors investigated the self-selected, overground walking patterns of 7 children (aged 11 months to 1 year, 5 months) at the initiation of walking (brand-new walkers [BNWs]) and for the next 6 months at 1-month intervals. Walking speed, stride length, and stride frequency increased significantly between the first 2 visits without significant changes in height and weight. The authors calculated sagittal plane angular accelerations of the center of mass over the foot for each step as an indicator of the escapement pulse. Results for the acceleration profiles changed after the 1st visit to positive, single-peaked accelerations that occurred < 0.20 s after initial foot contact. Increases in sagittal plane hip angular displacement and decreases in frontal plane pelvic angular displacement were observed. The pattern changes suggest that children quickly discover appropriately timed and directed escapements that initiate and support the conservative sagittal plane pendulum and spring dynamics observed in older children.     

Good and Bad Years: An Index of American Social,Economic, and Political Threat (1920–1986)

Information provided by 196 U.S. history professors, indicating the degree to which they considered each of the years from 1920 to 1986 threatening to the established order and way of life in America, was pooled to form a social, economic, and political threat (SEPT) index. Interrater reliability was high, and substantial test-retest reliability was evident for a selected subsample over a 6-month period. The index significantly correlated with 11 objective indices of threat, including the suicide rate, unemployment rate, rise and fall of common stocks, and number of military men on active duty. Several studies involving threat and authoritarianism were replicated and in some instances extended with the SEPT index (McCann & Stewin, 1984; Sales, 1972, 1973). The pseudo-archival SEPT index has utility when relatively global estimates of prevailing threat are required for historiometric research testing a diversity of hypotheses gleaned from psychological, sociological, historical, and political science theories.     

Cognitive Performance in Adolescence: Links With Early Maternal Stimulation and Children’s Anxious Behaviors

Abstract

This study tested a developmental model of cognitive performance in adolescence and explored potential mechanisms explaining the relations of early maternal stimulation and children’s anxious behaviors with adolescents’ cognitive performance. We utilized the NICHD SECCYD dataset (n?=?1,112). Measures included questionnaires, coded observations, and self-report measures from infancy to adolescence. Results revealed that children who experienced greater early maternal stimulation and less anxious behaviors had better cognitive performance at age 15. Children’s English self-efficacy, the quality of child–teacher relationships, and children’s behavioral classroom engagement in middle childhood mediated the relation between early maternal stimulation and adolescent cognitive performance. Identifying pathways from earlier maternal and children’s characteristics to children’s later cognitive performance is an important step toward further understanding why early precursors have a long lasting impact on cognitive performance, and has implications for educational settings.     

Studies of Abnormal Behavior in the Rat: XVII. Guidance Versus Trial and Error in the Alteration of Habits and Fixations

Formation of a God concept, in accordance with the developmental hypothesis of object relations theory, includes the utilization of representations acquired within the context of significant relationships. Previous researchers have attempted to determine the comparative extent to which parent representations give rise to an individual's God image. In this study, we measured the similarities between subjects' composite parental ratings and their image of God. As predicted, the parental composite was significantly closer to the God rating than were the singular parent representations.     

Inclusive Leadership and Innovative Work Behavior: Examination of LMX Perspective in Small Capitalized Textile Firms

The purpose of this paper is to explore the relationship between inclusive leadership, Leader-Member Exchange (LMX) and innovative work behavior (IWB) in employees of small capitalized textile firms of Pakistan. We hypothesized that LMX mediates the relationship between inclusive leadership and IWB. We collected data from 150 supervisors–subordinate dyads to test our hypotheses. We selected small capitalized firms because they are more innovative and change-oriented in order to enhance their innovativeness. Moreover, these firms enjoy the benefits of lack of bureaucracy and low resistance to change. Therefore, employees are better able to experience a close relationship with entrepreneurial leaders who tend to be inclusive, in order to facilitate the process of innovation. In line with these facts, our results also suggest that inclusive leadership is positively related with IWB and LMX partially mediates this relationship. The theoretical and practical implications of our findings are also discussed.     

Different forms of causation in dynamical systems: Determinism,pattern generation,and information

The standpoint that three fundamentally inequivalent classes of system behavior exist, which deserve separate tools for their characterization, is developed. These classes are: determinism, pattern generation, and information. A simple explanation for the origin of these classes is given. The three classes are shown to correspond to the different possible ways in which the properties of the components of a system unfold in the course of the system's processes. Determinism will be defined as a form of causation in which the properties causing the behavior are factually the same as the ones which for the observer specify the current conditions of the system. As a consequence, deterministic systems can be characterized by state equations that describe how the observable properties change. Pattern generation is characterized here as a form of causation in which the observable properties and the behavior‐generating properties correspond to each other as one to the many. Consequently, we experience in terms of the observable properties a branching behavior which is characterized by a pattern of selections at the branching points, a pattern that stands in close correspondence with the visually perceivable patterns and forms, generated by the system's dynamics. Information will be understood as a name for a process and an instance of causation where properties that cause behavior differ from those which we directly observe. The behavior of the system appears to be a consequence of the content of information hidden in the components. This information is, in turn, epistemologically equivalent to the very causal process in which it is unfolded.     

Dynamics of scientific change and cognitive science. An epistemological update / Dinámica de cambio y ciencias cognitivas. Una puesta al día epistemológica

Abstract

I explore two proposals on the dynamics of scientific change in the general philosophy of science and I evaluate the extent to which they can be applied in the cognitive sciences. I do this by paying special attention to the youth and diversity which characterize this field of scientific research. Firstly, I distinguish two kinds of uses of Kuhn’s work: direct but loose applications of Kuhnean concepts to the history of cognitive science, on the one hand, and indirect applications of certain aspects of Kuhnean ideas, on the other hand. Secondly, I criticize their pertinence on the basis of the secondary role which theories play in the field. Finally, I defend the fertility of the concept of ‘research tradition’ proposed by Laudan, by focusing on the previously highlighted set of idiosyncratic characteristics of the cognitive sciences.