How the Complexity of Psychological Processes Reframes the Issue of Reproducibility in Psychological Science.

In the past decade, various recommendations have been published to enhance the methodological rigor and publication standards in psychological science. However, adhering to these recommendations may have limited impact on the reproducibility of causal effects as long as psychological phenomena continue to be viewed as decomposable into separate and additive statistical structures of causal relationships. In this article, we show that (a) psychological phenomena are patterns emerging from nondecomposable and nonisolable complex processes that obey idiosyncratic nonlinear dynamics, (b) these processual features jeopardize the chances of standard reproducibility of statistical results, and (c) these features call on researchers to reconsider what can and should be reproduced, that is, the psychological processes per se, and the signatures of their complexity and dynamics. Accordingly, we argue for a greater consideration of process causality of psychological phenomena reflected by key properties of complex dynamical systems (CDSs). This implies developing and testing formal models of psychological dynamics, which can be implemented by computer simulation. The scope of the CDS paradigm and its convergences with other paradigms are discussed regarding the reproducibility issue. Ironically, the CDS approach could account for both reproducibility and nonreproducibility of the statistical effects usually sought in mainstream psychological science.

Dynamic Systems, Process and Development.

In this article, I answer the questions from Witherington and Boom's introduction to this special issue in the form of an imaginary interview, led by David Boom, equally imaginary editor of The Processual Inquirer, an obscure but interesting journal that appears in imaginary physical print only, and which, as a consequence, has so far left no traces on the Internet….

The Link between Microdevelopment and Long-Term Learning Trajectories in Science Learning.

Long-term learning trajectories evolve through microdevelopmental sequences (i.e., short-term processes of change during learning tasks) and depend on variability during and across learning tasks. The aim of this study is to examine the coupling between short-term teacher-student dynamics and students' long-term learning trajectories, thereby providing empirical support for the link between the short- and long-term time scale in cognitive development. For 31 students (ages 3-5 years) from regular and special education, five teacher-student interactions during science tasks were filmed and coded in real time with regard to the student's level of understanding and the teacher's support throughout the task. A hierarchical cluster analysis resulted in four different learning trajectories over the course of 1.5 years, labeled as a high-scoring, mid-scoring, fluctuating, and low-scoring group of students. When connecting these trajectories to microdevelopmental data, the interactions of the high-scoring students were characterized by more moment-to-moment variations in the teacher's support and student's level of understanding, while the low-scoring group had the least variability compared to the other groups. Students with emotional and behavioral disabilities were represented across all learning trajectories, despite frequent accounts in the literature on their significant academic delays.

Socio-Emotional Concern Dynamics in a Model of Real-Time Dyadic Interaction: Parent-Child Play in Autism.

We used a validated agent-based model-Socio-Emotional CONcern DynamicS (SECONDS)-to model real-time playful interaction between a child diagnosed with Autism Spectrum Disorders (ASD) and its parent. SECONDS provides a real-time (second-by-second) virtual environment that could be used for clinical trials and testing process-oriented explanations of ASD symptomatology. We conducted numerical experiments with SECONDS (1) for internal model validation comparing two parental behavioral strategies for stimulating social development in ASD (play-centered vs. initiative-centered) and (2) for empirical case-based model validation. We compared 2,000 simulated play sessions of two particular dyads with (second-by-second) time-series observations within 29 play sessions of a real parent-child dyad with ASD on six variables related to maintaining and initiating play. Overall, both simulated dyads provided a better fit to the observed dyad than reference null distributions. Given the idiosyncratic behaviors expected in ASD, the observed correspondence is non-trivial. Our results demonstrate the applicability of SECONDS to parent-child dyads in ASD. In the future, SECONDS could help design interventions for parental care in ASD.

Co-Adaptation Processes of Syntactic Complexity in Real-Time Kindergarten Teacher-Student Interactions.

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.

Dutch Adolescents' Everyday Expressions of Sexual Behavior Trajectories Over a 2-Year Period: A Mixed-Methods Study.

Using an extended definition of sexuality, this mixed-methods study builds on existing research into adolescents' emergent sexual development by longitudinally examining adolescents' sexual behavior trajectories (i.e., from less to more intimate sexual behavior). Over a 2-year period, 45 adolescents (M age = 15.9 years) reported on their sexual behavior using questionnaires and on their everyday expressions of sexuality in the form of semi-structured diaries. Cluster analysis using the questionnaire data identified three sexual behavior trajectories: a non-sexually active trajectory (meaning no or minor sexual behavior) (n = 29), a gradually sexually active trajectory (meaning step-by-step sexual behavior development) (n = 12), and a fast sexually active trajectory (meaning rapid sexual behavior development) (n = 4). Qualitative analysis using diaries revealed the following themes: romantic versus sex-related topics, desires, uncertainties, and references to the social context. In general, all adolescents reported more about romantic aspects of sexuality (than about sexual acts) in the diaries, regardless of their sexual behavior trajectory. Sexually active adolescents (i.e., gradual and fast) were more concerned with sexuality in their diaries, especially more with the physical aspects of sexuality, than non-active adolescents. Gradual adolescents experienced more desires about physical sexual contact and reported fewer references to their social network than non-active and fast adolescents. The findings suggest that sexual education that discusses the internal experiences of sexuality, such as feelings and thoughts, particularly the romantic aspects, may help adolescents process their preferences for different sexual and romantic acts and may contribute to healthy sexual development.

Attractor Dynamics of Dyadic Interaction: A Recurrence Based Analysis.

The aim of this study was to investigate interpersonal coordination in young children during dyadic problem solving, by using Cross-Recurrence Quantification Analysis (CRQA). We examined the interactions of seven dyads of children (Mage= 5.1 years) in a longitudinal design (6 sessions) with a sequence of problem-solving tasks increasing in difficulty. An innovative implementation of CRQA is presented in order to study the attractor dynamics of dyadic coordination. The analysis consisted of distinguishing two recurrent states in the relationship between children and the task. In other words, the analysis is focused on how the dyadic interaction oscillates between two stable states that for their recurrent presence are considered to be attractors. The distributed dyadic interaction (DDI) state indicates that both children contribute equally to the solution of the task. The unequal dyadic interaction (UDI) state indicating that only one of the children contributes actively to the solution of the task. Results showed that the DDI was more frequent than the UDI but that the dynamics of these two attractor states were quite similar. The behaviors within these states increased in complexity over time, although they did so in DDI more strongly than UDI. The overall recurrence, which indicates the global level of coordination between the individuals in the dyad across all time points, was moderately correlated with the performance of the children.

Embedding the psychosocial biographies of Olympic medalists in a (meta-)theoretical model of dynamic networks.

Based on in-depth interviews, Hardy et al. focused on the role of psychosocial factors in the development of elite and super-elite athletes. They reveal interesting differences and commonalities in the frequencies at which certain aspects related to life events, personality, contextual factors, etc. were reported. Here, we argue that insights in the development of (super-)elite athletes will advance if we go beyond explanations in the frequency-domain, and search for process explanations in the time-domain. This means that we should investigate how athletes develop from one time point to the next, and the next, etc., thereby examining how (psychosocial) factors change and combine across time, as well as how the timing of events can shape an athlete's further developmental trajectory. We therefore present a process-oriented dynamic network model of talent development, assuming that (super-)elite performance develops out of structures of dynamically interacting (psychosocial) factors, which we illustrate using the outcomes of Hardy et al.

Attractor States in Teaching and Learning Processes: A Study of Out-of-School Science Education.

In order for out-of-school science activities that take place during school hours but outside the school context to be successful, instructors must have sufficient pedagogical content knowledge (PCK) to guarantee high-quality teaching and learning. We argue that PCK is a quality of the instructor-pupil system that is constructed in real-time interaction. When PCK is evident in real-time interaction, we define it as Expressed Pedagogical Content Knowledge (EPCK). The aim of this study is to empirically explore whether EPCK shows a systematic pattern of variation, and if so whether the pattern occurs in recurrent and temporary stable attractor states as predicted in the complex dynamic systems theory. This study concerned nine out-of-school activities in which pupils of upper primary school classes participated. A multivariate coding scheme was used to capture EPCK in real time. A principal component analysis of the time series of all the variables reduced the number of components. A cluster revealed general descriptions of the components across all cases. Cluster analyses of individual cases divided the time series into sequences, revealing High-, Low-, and Non-EPCK states. High-EPCK attractor states emerged at particular moments during activities, rather than being present all the time. Such High-EPCK attractor states were only found in a few cases, namely those where the pupils were prepared for the visit and the instructors were trained.

Trajectories of scientific reasoning: A microgenetic study on children's inquiry functioning.

From the literature, we know that young children engage in inquiry as an organized activity aimed either at confirming or refuting the relevance of certain ideas. The current study provides a characterization of changes in inquiry using a multiple case study of four 5-year old children. Three computer-based tasks were presented to the children as multivariable problem solving situations concerning moving objects. A description of the temporal unfolding of real-time action on a short-term time scale and long-term time scale of learning and development is provided. The results indicated that the development of inquiry did not follow linear growth but included advances and relapses, exploratory states and transitions. The data were compatible with the view that the child's thinking and acting form a complex dynamic system.

"How do I feel today?" An Analysis of HRQOL Variability among Institutionalized Older Adults.

Intra-individual variability is a central topic in Nonlinear Dynamical Systems (NDS) studies of human development, because the theory predicts that particular forms or properties of intra-individual variability will serve as indicators or predictors of bifurcations, and stable states in individual development. Currently, there are almost no studies that address intra-individual changes and variability of Health Related Quality of Life in old age. The main aim of this paper is to analyze the role of day-to-day HRQOL variability and long term HRQOL and disability development in a sample of institutionalized older adults. 22 older adults took part in this longitudinal study. Daily diary-based assessments were made for a period of 100 days. Furthermore, monthly assessments of HRQOL and disability with validated questionnaires were performed. The intra individual variability on a day-to-day basis was found to be related to HRQOL and disability development. Furthermore, life events as operationalized by extreme values in HRQOL were related to the level of day-to-day HRQOL variability. As predicted by NDS theory, day-to-day variability emerges as an important indicator of levels of and changes in HRQOL and disability and as such, it may be an important indicator of developmental processes in old age.

A Dynamic Network Model to Explain the Development of Excellent Human Performance.

Across different domains, from sports to science, some individuals accomplish excellent levels of performance. For over 150 years, researchers have debated the roles of specific nature and nurture components to develop excellence. In this article, we argue that the key to excellence does not reside in specific underlying components, but rather in the ongoing interactions among the components. We propose that excellence emerges out of dynamic networks consisting of idiosyncratic mixtures of interacting components such as genetic endowment, motivation, practice, and coaching. Using computer simulations we demonstrate that the dynamic network model accurately predicts typical properties of excellence reported in the literature, such as the idiosyncratic developmental trajectories leading to excellence and the highly skewed distributions of productivity present in virtually any achievement domain. Based on this novel theoretical perspective on excellent human performance, this article concludes by suggesting policy implications and directions for future research.

Asymmetric Dynamic Attunement of Speech and Gestures in the Construction of Children's Understanding.

As children learn they use their speech to express words and their hands to gesture. This study investigates the interplay between real-time gestures and speech as children construct cognitive understanding during a hands-on science task. 12 children (M = 6, F = 6) from Kindergarten (n = 5) and first grade (n = 7) participated in this study. Each verbal utterance and gesture during the task were coded, on a complexity scale derived from dynamic skill theory. To explore the interplay between speech and gestures, we applied a cross recurrence quantification analysis (CRQA) to the two coupled time series of the skill levels of verbalizations and gestures. The analysis focused on (1) the temporal relation between gestures and speech, (2) the relative strength and direction of the interaction between gestures and speech, (3) the relative strength and direction between gestures and speech for different levels of understanding, and (4) relations between CRQA measures and other child characteristics. The results show that older and younger children differ in the (temporal) asymmetry in the gestures-speech interaction. For younger children, the balance leans more toward gestures leading speech in time, while the balance leans more toward speech leading gestures for older children. Secondly, at the group level, speech attracts gestures in a more dynamically stable fashion than vice versa, and this asymmetry in gestures and speech extends to lower and higher understanding levels. Yet, for older children, the mutual coupling between gestures and speech is more dynamically stable regarding the higher understanding levels. Gestures and speech are more synchronized in time as children are older. A higher score on schools' language tests is related to speech attracting gestures more rigidly and more asymmetry between gestures and speech, only for the less difficult understanding levels. A higher score on math or past science tasks is related to less asymmetry between gestures and speech. The picture that emerges from our analyses suggests that the relation between gestures, speech and cognition is more complex than previously thought. We suggest that temporal differences and asymmetry in influence between gestures and speech arise from simultaneous coordination of synergies.

Psychological Momentum During and Across Sports Matches: Evidence for Interconnected Time Scales.

This study on psychological momentum (PM) in sports provides the first experimental test of an interconnection between short-term PM (during a match) and long-term PM (across a series of matches). Twenty-two competitive athletes were striving to win a prize during a rowing-ergometer tournament, consisting of manipulated races. As hypothesized, athletes who had developed long-term positive PM after two successful races were less sensitive to a negative momentum scenario in the third race, compared with athletes who had developed long-term negative PM after two unsuccessful races. More specifically, the exerted efforts, perceptions of momentum, and self-efficacy were higher for participants who had developed long-term positive PM, and their perceptions of momentum and self-efficacy decreased less rapidly. These results illustrate a typical complex dynamical systems property, namely interconnected time scales, and provide deeper insights into the dynamical nature of PM.

Non-linearities in Theory-of-Mind Development.

Research on Theory-of-Mind (ToM) has mainly focused on ages of core ToM development. This article follows a quantitative approach focusing on the level of ToM understanding on a measurement scale, the ToM Storybooks, in 324 typically developing children between 3 and 11 years of age. It deals with the eventual occurrence of developmental non-linearities in ToM functioning, using smoothing techniques, dynamic growth model building and additional indicators, namely moving skewness, moving growth rate changes and moving variability. The ToM sum-scores showed an overall developmental trend that leveled off toward the age of 10 years. Within this overall trend two non-linearities in the group-based change pattern were found: a plateau at the age of around 56 months and a dip at the age of 72-78 months. These temporary regressions in ToM sum-score were accompanied by a decrease in growth rate and variability, and a change in skewness of the ToM data, all suggesting a developmental shift in ToM understanding. The temporary decreases also occurred in the different ToM sub-scores and most clearly so in the core ToM component of beliefs. It was also found that girls had an earlier growth spurt than boys and that the underlying developmental path was more salient in girls than in boys. The consequences of these findings are discussed from various theoretical points of view, with an emphasis on a dynamic systems interpretation of the underlying developmental paths.

A quantitative dynamic systems model of health-related quality of life among older adults.

Health-related quality of life (HRQOL) is a person-centered concept. The analysis of HRQOL is highly relevant in the aged population, which is generally suffering from health decline. Starting from a conceptual dynamic systems model that describes the development of HRQOL in individuals over time, this study aims to develop and test a quantitative dynamic systems model, in order to reveal the possible dynamic trends of HRQOL among older adults. The model is tested in different ways: first, with a calibration procedure to test whether the model produces theoretically plausible results, and second, with a preliminary validation procedure using empirical data of 194 older adults. This first validation tested the prediction that given a particular starting point (first empirical data point), the model will generate dynamic trajectories that lead to the observed endpoint (second empirical data point). The analyses reveal that the quantitative model produces theoretically plausible trajectories, thus providing support for the calibration procedure. Furthermore, the analyses of validation show a good fit between empirical and simulated data. In fact, no differences were found in the comparison between empirical and simulated final data for the same subgroup of participants, whereas the comparison between different subgroups of people resulted in significant differences. These data provide an initial basis of evidence for the dynamic nature of HRQOL during the aging process. Therefore, these data may give new theoretical and applied insights into the study of HRQOL and its development with time in the aging population.

Pink Noise in Rowing Ergometer Performance and the Role of Skill Level.

The aim of this study was to examine (1) the temporal structures of variation in rowers' (natural) ergometer strokes to make inferences about the underlying motor organization, and (2) the relation between these temporal structures and skill level. Four high-skilled and five lower-skilled rowers completed 550 strokes on a rowing ergometer. Detrended Fluctuation Analysis was used to quantify the temporal structure of the intervals between force peaks. Results showed that the temporal structure differed from random, and revealed prominent patterns of pink noise for each rower. Furthermore, the high-skilled rowers demonstrated more pink noise than the lower-skilled rowers. The presence of pink noise suggeststhat rowing performance emerges from the coordination among interacting component processes across multiple time scales. The difference in noise pattern between high-skilled and lower-skilled athletes indicates that the complexity of athletes' motor organization is a potential key characteristic of elite performance.

Associations between developmental trajectories of movement variety and visual attention in fullterm and preterm infants during the first six months postterm.

BACKGROUND: During early infancy major developmental changes, both in the variety of body movements and in visual attention, help the infant to explore its surroundings. Both behaviours depend on a gradual shift from subcortical to cortical functioning. AIMS: First, to determine whether preterms reach mature levels of movement variety (the number of different movement patterns) and visual attention earlier than fullterms. Second, to determine whether individual developmental trajectories of movement variety and visual attention were associated. Finally, we compared the associations of developmental trajectories between fullterm and preterm infants. STUDY DESIGN: In this longitudinal study, 20 fullterm and 9 low-risk preterm infants performed a visual disengagement task every four weeks from six weeks until six months postterm. For each infant we drew up developmental trajectories for movement variety, and for frequencies and latencies of looks. We analyzed the developmental trajectories by means of general linear model (GLM) repeated measures and Monte Carlo analyses. RESULTS: In comparison to fullterms, preterm infants showed a similar increase in movement variety over time (F(4,108)=0.27; partial eta(2)=0.01; P=.90). Visual attention reached mature levels four weeks earlier than movement variety. This effect was stronger in fullterm infants. Neither in fullterm nor in preterm infants did we find an association between the developmental trajectories of movement variety and visual attention. P values ranged from .37 to .99. CONCLUSIONS: During the first 6 months postterm, movement variety and visual attention developed independently. Temporarily, preterm exposure to the extrauterine environment led to shorter latencies of looks but it did not affect developmental trajectories of frequencies of looks and movement variety.

Collaborative play in young children as a complex dynamic system: revealing gender related differences.

This study was focused on the role of gender-related differences in collaborative play, by examining properties of play as a complex system, and by using micro-genetic analysis techniques. A complex dynamic systems model of dyadic play was used to make predictions with regard to duration and number of contact-episodes during play of same-sex dyads, both on the micro- (i.e., per individual session), meso- (i.e., in smoothed data), and macro time scale (i.e., the change over six consecutive play sessions). The empirical data came from a study that examined the collaborative play skills of children who experienced six twenty minute play sessions within a three week period of time. Monte Carlo permutation analyses were used to compare model predictions and empirical data. The findings point to strongly asymmetric distributions in the duration and number of contact episodes in all dyads over the six sessions, as a direct consequence of the underlying dynamics of the play system. The model prediction that girls-dyads would show longer contact episodes than boys-dyads was confirmed, but the prediction regarding the difference in number of peaks was not confirmed. In addition, the majority of the model predictions regarding changes over the course of six sessions were consistent with the data. That is, the average duration and the maximum duration of contact-episodes increases both in boys-dyads and girls-dyads, but differences occur in the strength of the increase. Contrary to expectation, the number of contact-episodes decreases both in boys-dyads and in girls-dyads.

How psychological and behavioral team states change during positive and negative momentum.

In business and sports, teams often experience periods of positive and negative momentum while pursuing their goals. However, researchers have not yet been able to provide insights into how psychological and behavioral states actually change during positive and negative team momentum. In the current study we aimed to provide these insights by introducing an experimental dynamical research design. Rowing pairs had to compete against a virtual opponent on rowing ergometers, while a screen in front of the team broadcasted the ongoing race. The race was manipulated so that the team's rowing avatar gradually progressed (positive momentum) or regressed (negative momentum) in relation to the victory. The participants responded verbally to collective efficacy and task cohesion items appearing on the screen each minute. In addition, effort exertion and interpersonal coordination were continuously measured. Our results showed negative psychological changes (perceptions of collective efficacy and task cohesion) during negative team momentum, which were stronger than the positive changes during positive team momentum. Moreover, teams' exerted efforts rapidly decreased during negative momentum, whereas positive momentum accompanied a more variable and adaptive sequence of effort exertion. Finally, the interpersonal coordination was worse during negative momentum than during positive momentum. These results provide the first empirical insights into actual team momentum dynamics, and demonstrate how a dynamical research approach significantly contributes to current knowledge on psychological and behavioral processes.