Nonlinear Dynamics Psychology and Life Sciences最新文献

The study presents further development and application of generalized multiplicative models (GMultM) for assessing outcomes in psychotherapy. GMultM is a flexible nonlinear regression method which is able to predict the impact of subjects' psychological variables (common factors) as well as theirchanges on the outcomes of cognitive-behavioral therapy and rhythmic-movement therapy. The main objectives of our present study are (a) to construct GMultM with the aim to predict the impact of pre-treatment scores of subject'psychological variables (common factors) on the outcome of cognitive-behavioral therapy (CBT) for disordered eating behaviors and obesity; (b) to employ GMultM to model the change of Body Mass Index (BMI) in each participant (non18 responders to CBT treatment) individually after sessions of rhythmic movement therapy (RMT); (c) to demonstrate that GMultM is able to predict whether intervention-related changes in several psychological variables are mechanisms underlying BMI change in each individual subject participating in RMT intervention program. The processes of model construction, identification of parameters and validation procedure using data from CBT program are described. Sensitivity analysis of the developed model was provided. Results revealed that: (a) the GMultM not only predicts the outcomes of psychotherapy satisfactorily but also allows obtaining the partial response functions of psychological predictors of weight loss directly as a result of estimation of model's parameters; (b) GMultM predicts the changes in BMI after RMT intervention in each participant satisfactorily and thus can be applied as the individualized assessment tool for psychotherapy's outcome.

In social contexts of racket sports, the interactive behaviour between players in the same team is supported by visual coupling. Visual cues allow the players to dynamically coordinate their movements and maintain a suitable interpersonal distance, thereby decreasing the odds of missing score a point. The dynamic feature of this interpersonal coordination requiring reciprocal nonlinear behavioural adjustments to stabilize a relative position may be considered an interpersonal synergy. We used the Uncontrolled Manifold Hypothesis (UCM) methodology to test this hypothesis and capture interpersonal synergies in badminton doubles. The variability of the distance between players was utilized as a performance variable and the variability of player velocities were used as task-relevant elements. To our knowledge, this is the first study to identify interpersonal synergies in a cooperative task in badminton doubles at different moments within the same rally. Eight male badminton players were randomly assigned in four doubles with similar technical and tactical level. The participants performed 154 trials over two matches. Interpersonal synergies were found on approximately half of the trials examined. Moreover, the results reveal that shortest interpersonal distances create better conditions for the nonlinear adjustments required for interpersonal synergy formation in badminton doubles.

The development of new theories, mathematical methods and models for effective control of complex systems is one of the main problems for modern science. Biological systems are complex and hierarchically organized, with the behaviour of higher levels influencing the dynamics of the lower ones and vice versa. Hierarchical organization can be observed from subcellular to supercellular levels. When biological systems are far from their steady states, then nonlinear dependences take place, and a slight external impact can cause unexpected and unpredictable (chaotic, irregular) behaviour in these systems, resulting in fractal hierarchical structures. By examining tumours as strange (chaotic) attractors, we define in this article the hypothesis that the cause of their occurrence, development and spread (metastasis) is due to disorders in the hierarchical structure and integration of cell signalling pathways in tumour cells. An essential point in this article is the thesis (contrary to the view that the only causality in hierarchical systems is physical causality, i.e. there is no "top-down,' "holistic causality,' "intelligent causality,' etc.) that hierarchical systems are built on the principle of communication. Intelligent systems (in particular biological) that do not interact as mechanical objects, but on the basis of different meanings of biochemical signals obtained after their interpretation, participate in this communication.

This article investigates the chaotic relationship among inflation rate, unemployment rate and oil prices over the period of January, 1974-October, 2018 in the USA. This study complements the previous studies on this subject. However, it differs from the existing literature in examination of inflation-unemployment trade-off by a neural network model in which oil prices are considered as an exogenous variable, and in analyzing the chaotic causality relation among the variables by Hristu-Varsakelis and Kyrtsou and Bai nonlinear causality tests. The results first suggested by a class of neural network model, which was the multi-layer perceptron (MLP), pointed out an important relation among the analyzed variables. Accordingly, oil price changes have substantial effect on unemployment and inflation. Following, the empirical findings of Hristu-Varsakelis and Kyrtsou and Bai nonlinear causality tests show that there is a unidirectional chaotic relation from oil price to inflation, from oil price to unemployment and from inflation to unemployment.

The problem being investigated is the spontaneous rise of the herd instinct in an artificial population, where the population members have no explicit stimuli for such instinct implanted in their original behavior patterns. The simulations are focused on the creation of the herd instinct in the population that originally does not reveal the gregarious behavior. In this agent-based model, the members of the population (agents) move over a limited region, look for renewable food, reproduce, escape a threat and die. The evolution of the herd instinct is simulated. No explicit instinct is imposed on the agents. It is pointed out that both the search for food and fear, are factors that cause the rise of the herd instinct. The evolution of the amount of the instinct is slow and needs long model time intervals, running over several hundred generations of the agents. The herd instinct is inherited from parent agents during the reproduction, with certain random deviation. This makes the total amount of the instinct evolve and reach an optimal level.

Human dyads and larger teams tend to acquire synchronized movements and autonomic arousal levels while working together or simply socializing. The synchronization of arousal patterns is of theoretical interest for group dynamics because they may add predictive value to the dynamics of group cohesion and team performance. This study examined the four-way relationship among experimental conditions: team size, task difficulty, time pressure (between-subjects) and subsequent experimental sessions (within-subjects). Previously, we have shown these conditions affect subjective ratings of workload that come from individual and group-level sources, synchronization of arousal, and team performance. In an experiment involving an emergency response (ER) simulation, 360 undergraduates, who were wearing electrodermal sensors, were organized into 44 teams of various sizes. Workload was experimentally varied by team size (three, four, seven or eight members), number of opponents (one or two), and time pressure; the latter was introduced sooner or later across two experimental sessions. Results showed that the experimental conditions affected synchronization levels, either at the beginning of a session or in the middle; synchronization and experimental conditions were not directly related to team performance. Subjective group workload ratings of the coordination demand of the task correlated with synchronization at the beginning of a session while team satisfaction was correlated with greater synchrony at the end of a session. The competitive nature of the ER task, as compared to strictly cooperative tasks, could be responsible for the complexity of these empirical relationships.

Under the premise that language learning is bidirectional in nature, this study aimed to investigate syntactic coordination within teacher-student interactions by using cross-recurrence quantification analysis (CRQA). Seven teachers' and a group of their students' interactions were repeatedly measured in the course of an intervention in early science education. Results showed changes in the proportion of recurrent points; in case of simple sentences teachers and students became less coordinated over time, whereas in case of complex sentences teachers and students showed increasing coordination. Results also revealed less rigid (more flexible) syntactic coordination, although there were no changes in the relative contribution of teacher and students to this. In the light of the intervention under investigation this is an important result. This means that teachers and students learn to use more complex language and coordinate their language complexity better in order to co-construct science discourse. The application of CRQA provides new insights and contributes to better understanding of the dynamics of syntactic coordination.

In the present paper, the Rosenzweig-MacArthur predator-prey model (RM), which is a bitrophic food chain model, is considered. We develop the model by adding two assumptions. First, we assume that both species are of economic interest, that is can be harvested. Second, we assume that each specie has its own time scale which range from fast for the prey to slow for the predator. We consider that both the death rate and the catch of the predator are very small which leads to a fast-slow dynamical system. That is, the RM model is transformed into a singular perturbed system with a perturbation parameter E in the set [0,1]. The existence and stability of equilibria are discussed for E > 0. The model experiences both transcritical and Hopf bifurcations for E>0. The singular perturbation model at E = 0 is discussed by separating the system into two subsystems; fast and slow and studying them simultaneously. When 0

Previous research has found that spontaneous synchronization of bodily movements emerges when people interact. This dynamic interactional synchrony occurs in all kinds of everyday movements and has been demonstrated empirically in a variety of social contexts. The objective of this study is to advance our understanding of the dynamical processes that enable the spontaneous and fluid coordination of movements in more naturalistic social interactions. We measured the degree of interactional synchrony of 44 dyads who enacted a series of knock-knock jokes together and we manipulated the perceptual information available (using auditory occlusion) and the individuals' dynamical motor 'signatures' by weighting their limbs. Our analyses using relative phase and fractal/multifractal measures support the conclusion that both local and global dynamical synchronization processes sustain the interactional fluidity seen in conversational exchanges and provide an embodied foundation for how humans connect and cooperate socially.

Psychoanalysts and therapists have noticed that the increase of the reconciliation time, i.e., the period of dissatisfaction that two lovers need to return to their positive equilibrium after a dispute, is often a warning sign of an impending consistent drop of quality of the relationship, possibly followed by a breakup (e.g., a divorce). Here this rule is investigated and shown to be the logical consequence of the attitude of individuals (here called secure) who increase their reaction when their partners get more involved. The analysis is carried out with a well-known and repeatedly validated mathematical model composed of two nonlinear differential equations and the rule follows from the discovery that the model has catastrophic bifurcations with respect to the psychophysical traits of the partners. Thus, for example, negative trends in the appeal of the partners or in the reactiveness to it slowly but inevitably push couples toward a tipping point, from which a critical transition can originate. Since the rule is here justified only for couples composed of secure individuals, finding out if it holds also for other couples remains an interesting open problem.