Does popularity determine who leads in a dyadic cooperative task? Subtle differences between children with and without developmental disabilities.

BACKGROUND: Popular indivuals are usually academically high achiveving and also often leaders. Children with developmental disabilities are usually not popular among their peers. In dyadic cooperative tasks, the popular member is often the leader, as shown by self-reports and observational research. It is unknown whether this macro-level behaviour is reflected in micro-level synchronisation patterns of the movements of dyads who are engaged in a cooperative task. AIMS: The goal of the present study was to investigate whether popularity differentially affected the leading-following behaviour of dyads consisting of children with and without developmental disabilities. METHODS AND PROCEDURES: Children with (n = 106) and without (n = 183) developmental disabilities performed a tangram puzzle task individually and cooperatively. While performing the task, they stood on a Nintendo Wii Balance Board that registered their postural sway. OUTCOMES AND RESULTS: Although we found some similarities between dyads with and without a developmental disability based on both popularity and task performance, the most striking difference occurred in low performing dyads. In those, dyads with a developmental disability had no clear leader or follower. CONCLUSION: Especially in dyads with developmental disabilities it is important that there are clear roles, since the worst performance was observed when roles were absent.

What Enables Novel Thoughts? The Temporal Structure of Associations and Its Relationship to Divergent Thinking.

The aim of the current study is to enhance our understanding of cognitive creativity, specifically divergent thinking, by employing an interdisciplinary methodological approach. By integrating methodology from computational linguistics and complex systems into creativity research, the current study aims to shed light on the relationship between divergent thinking and the temporal structure of semantic associations. In complex systems, temporal structures can be described on a continuum from random to flexible-stable and to persistent. Random structures are highly unpredictable, persistent structures are highly predictable, and flexible-stable structures are in-between, they are partly predictable from previous observations. Temporal structures of associations that are random (e.g., dog-graveyard-north pole) or persistent (e.g., dog-cat-rat) are hypothesized to be detrimental to divergent thinking. However, a flexible-stable structure (e.g., dog-police-drugs) is hypothesized to be related to enhanced divergent thinking (inverted-U). This notion was tested (N = 59) in an association chain task, combined with a frequently used measure of divergent thinking (i.e., Alternative Uses Test). Latent Semantic Analysis from computational linguistics was used to quantify the associations, and methods from complex systems in form of Power Spectral Density analysis and detrended fluctuation analysis were used to estimate the temporal structure of those associations. Although the current study does not confirm that a flexible-stable (vs. random/persistent) temporal structure of associations is related to enhanced divergent thinking skills, it hopefully challenges fellow researchers to refine the recent methodological developments for assessing the (temporal) structure of associations. Moreover, the current cross-fertilization of methodological approaches may inspire creativity researchers to take advantage of other fields' ideas and methods. To derive a theoretically sound cognitive theory of creativity, it is important to integrate research ideas and empirical methods from a variety of disciplines.

Cooperative Learning and Interpersonal Synchrony.

Cooperative learning has been shown to result in better task performance, compared to individual and competitive learning, and can lead to positive social effects. However, potential working mechanisms at a micro level remain unexplored. One potential working mechanism might be the level of interpersonal synchrony between cooperating individuals. It has been shown that increased levels of interpersonal synchrony are related to better cognitive performance (e.g., increased memory). Social factors also appear to be affected by the level of interpersonal synchrony, with more interpersonal synchrony leading to increased likeability. In the present study, interpersonal synchrony of postural sway and its relation to task performance and social factors (i.e., popularity, social acceptance, and likeability) was examined. To test this, 183 dyads performed a tangram task while each child stood on a Nintendo Wii Balance Board that recorded their postural sway. The results showed that lower levels of interpersonal synchrony were related to better task performance and those dyads who were on average more popular synchronized more. These results contradict previous findings. It is suggested that for task performance, a more loosely coupled system is better than a synchronized system. In terms of social competence, dyad popularity was associated with more interpersonal synchrony.

Progress in reading and spelling of dyslexic children is not affected by executive functioning.

Although poor reading and spelling skills have been associated with weak skills of executive functioning (EF), its role in literacy is not undisputed. Because EF has different theoretical underpinnings, methods of analysis and of assessing, it has led to varying and often contrasting results in its effects in children with dyslexia. The present study has two goals. The first goal is to establish the relationship between a large number of EF tasks and reading and spelling skills in a large number of Dutch dyslexic children (n = 229). More interesting, however, is the second aim. To what extent do EF skills predict progress in reading and spelling in dyslexic children who attended a remediation programme? The results revealed small, but significant relationships between EF and reading and spelling skills, but no relationships between EF and progress in reading and spelling. It is concluded that training EF skills is unlikely to enhance reading and spelling skills.

Dyslexic and skilled reading dynamics are self-similar.

The shape of a word pronunciation time distribution supplies information about the dynamic interactions that support reading performance. Speeded word-naming pronunciation and response time distributions were collected from 20 sixth grade Dutch students with dyslexia and 23 age-matched controls. The participants' pronunciation times were modeled and contrasted with a lognormal inverse power-law mixture distribution. Identical contrasts were also conducted on the same participants' response time distributions derived from flanker, color-naming, and arithmetic tasks. Results indicated that children with dyslexia yield slower, broader, and more variable pronunciation time distributions than their age-matched counterparts. This difference approximated a self-similar rescaling between the two group's aggregate pronunciation time distributions. Moreover, children with dyslexia produced similar, but less prominent trends toward slower and more variable performance across the three non-reading tasks. The outcomes support a proportional continuum rather than a localized deficit account of dyslexia. The mixture distribution's success at describing the participants' pronunciation and response time distributions suggests that differences in proportional contingencies among low-level neurophysiological, perceptual, and cognitive processes likely play a prominent role in the etiology of dyslexia.

Does sample rate introduce an artifact in spectral analysis of continuous processes?

Spectral analysis is a widely used method to estimate 1/f(α) noise in behavioral and physiological data series. The aim of this paper is to achieve a more solid appreciation for the effects of periodic sampling on the outcomes of spectral analysis. It is shown that spectral analysis is biased by the choice of sample rate because denser sampling comes with lower amplitude fluctuations at the highest frequencies. Here we introduce an analytical strategy that compensates for this effect by focusing on a fixed amount, rather than a fixed percentage of the lowest frequencies in a power spectrum. Using this strategy, estimates of the degree of 1/f(α) noise become robust against sample rate conversion and more sensitive overall. Altogether, the present contribution may shed new light on known discrepancies in the psychological literature on 1/f(α) noise, and may provide a means to achieve a more solid framework for 1/f(α) noise in continuous processes.

Contemporary theories of 1/f noise in motor control.

1/f noise has been discovered in a number of time series collected in psychological and behavioral experiments. This ubiquitous phenomenon has been ignored for a long time and classical models were not designed for accounting for these long-range correlations. The aim of this paper is to present and discuss contrasted theoretical perspectives on 1/f noise, in order to provide a comprehensive overview of current debates in this domain. In a first part, we propose a formal definition of the phenomenon of 1/f noise, and we present some commonly used methods for measuring long-range correlations in time series. In a second part, we develop a theoretical position that considers 1/f noise as the hallmark of system complexity. From this point of view, 1/f noise emerges from the coordination of the many elements that compose the system. In a third part, we present a theoretical counterpoint suggesting that 1/f noise could emerge from localized sources within the system. In conclusion, we try to draw some lines of reasoning for going beyond the opposition between these two approaches.

1/f scaling in movement time changes with practice in precision aiming.

When people perform repeated goal-directed movements, consecutive movement durations inevitably vary over trials, in poor as well as in skilled performances. The well-established paradigm of precision-aiming is taken as a methodological framework here. Evidence is provided that movement variability in closed tasks is not a random phenomenon, but rather shows a coherent temporal structure, referred to as 1/f scaling. The scaling relation appears more clearly as participants become trained in a highly constrained motor task. Also Recurrence Quantification Analysis (RQA) and Sample Entropy (SampEn) as analytic tools show that variation of movement times becomes less random and more patterned with motor learning. This suggests that motor learning can be regarded as an emergent, dynamical fusing of collaborating subsystems into a lower-dimensional organization. These results support the idea that 1/f scaling is ubiquitous throughout the cognitive system, and suggest that it plays a fundamental role in the coordination of cognitive as well as motor function.