Revealing the invisible hand: The role of teachers in children's peer experiences

To introduce this special issue, the concept of the teacher as an “invisible hand” is presented as a metaphor to describe the potentially influential but relatively understudied contribution that educators are likely to have on children’s peer relationships and their broader interpersonal growth. Building from conceptual work distinguishing between the role of adults and peers in children’s social development, we summarize empirical support for the view that teachers are in a position to develop and guide the classroom as a society by simultaneously directing institutional expectations while also providing students with opportunities to collectively construct their own peer culture. Key social development constructs are reviewed from this lens, and the four articles and two commentaries that constitute this special issue are discussed in relation to their contributions to clarifying and extending current views of the role of teachers in school social dynamics. We conclude by considering intervention implications of this work, and we argue that teachers are the one professional in a child’s life who have the opportunity to view the whole child in relation to the social ecology in which he or she is embedded.     

Coming together and remaining a part: Development of a group-as-a-whole compass. Part II

Group-as-a-whole theory is an attempt to explain the collaboration and synergy that results when patients share their care. The art and science of treating individuals within psychotherapy groups is enriched by an understanding of the unique mediums ³ through which a group comes into being and the more general domains within which it comes to be known. This paper continues the development of a group-as-a-whole compass, as an integration of extant models and theories (Ettin, 1996). The focus shifts from conceptual and spatial models to an exploration of the cultural and relational processes that make up whole-group functioning. The paper comes full circle with hypotheses drawn about how a psychotherapy group, as a holistic phenomenon, is composed and maintained.Private practice, East Brunswick, New Jersey.     

Silence and survival: Working with strategies of denial in families of traumatized pre-school children

Silence and denial about previous traumatic experiences are common features in families exposed to organized violence. Mutual protection between family members, and especially between parents and children, is seen as the fundament for the silencing of traumatic experiences. This strategy is suggested to have adaptive advantages in dangerous situations in general, where it serves the function of saving the child's internal representations of his/her parents as secure bases. If, however, the dangerous situation escalates and a psychic trauma cannot be avoided, the strategy of mutual silence concerning the event(s) becomes an obstacle for giving traumatized children parental support and professional treatment. It is argued that clinicians need to take seriously the strong reasons families have for upholding their strategy of denial, if they want to help traumatized families to a better functioning. A case presentation is made to illustrate how it is possible to use refugee children's re-enacting play as a source of information about past traumatic events in order to change destructive post-traumatic family dynamics and improve parental support to the child.     

Coordination Dynamics of the Horse-Rider System

The authors studied the interaction between rider and horse by measuring their ensemble motions in a trot sequence, comparing 1 expert and 1 novice rider. Whereas the novice's movements displayed transient departures from phase synchrony, the expert's motions were continuously phase-matched with those of the horse. The tight ensemble synchrony between the expert and the horse was accompanied by an increase in the temporal regularity of the oscillations of the trunk of the horse. Observed differences between expert and novice riders indicated that phase synchronization is by no means perfect but requires extended practice. Points of contact between horse and rider may haptically convey effective communication between them.     

Prediction during statistical learning, and implications for the implicit/explicit divide

Accounts of statistical learning, both implicit and explicit, often invoke predictive processes as central to learning, yet practically all experiments employ non-predictive measures during training. We argue that the common theoretical assumption of anticipation and prediction needs clearer, more direct evidence for it during learning. We offer a novel experimental context to explore prediction, and report results from a simple sequential learning task designed to promote predictive behaviors in participants as they responded to a short sequence of simple stimulus events. Predictive tendencies in participants were measured using their computer mouse, the trajectories of which served as a means of tapping into predictive behavior while participants were exposed to very short and simple sequences of events. A total of 143 participants were randomly assigned to stimulus sequences along a continuum of regularity. Analysis of computer-mouse trajectories revealed that (a) participants almost always anticipate events in some manner, (b) participants exhibit two stable patterns of behavior, either reacting to vs. predicting future events, (c) the extent to which participants predict relates to performance on a recall test, and (d) explicit reports of perceiving patterns in the brief sequence correlates with extent of prediction. We end with a discussion of implicit and explicit statistical learning and of the role prediction may play in both kinds of learning.     

儿童歧视知觉模型述评

Brown和Bigler提出了儿童歧视知觉模型,分析了歧视知觉的三个影响因素:认知因素、情景因素和个体差异因素,每个因素都包含了多个影响儿童歧视知觉的子因素。该模型展示了这些因素影响儿童歧视知觉的机制。完善该模型需要探讨其与信息加工理论、发展群际理论、主观群体动力学模型的兼容性。歧视知觉的类型需要进一步细化,因此在综合主观群体动力学模型和发展模型的基础上提出了歧视知觉的分类方案。未来研究还要进一步探讨情绪、文化以及年龄因素对儿童歧视知觉的影响,并探讨该模型对歧视干预的意义。     

Why don’t well-educated adults understand accumulation? A challenge to researchers,educators, and citizens

Accumulation is a fundamental process in dynamic systems: inventory accumulates production less shipments; the national debt accumulates the federal deficit. Effective decision making in such systems requires an understanding of the relationship between stocks and the flows that alter them. However, highly educated people are often unable to infer the behavior of simple stock–flow systems. In a series of experiments we demonstrate that poor understanding of accumulation, termed stock–flow failure, is a fundamental reasoning error. Persistent poor performance is not attributable to an inability to interpret graphs, lack of contextual knowledge, motivation, or cognitive capacity. Rather, stock–flow failure is a robust phenomenon that appears to be rooted in failure to appreciate the most basic principles of accumulation, leading to the use of inappropriate heuristics. We show that many people, including highly educated individuals with strong technical training, use what we term the “correlation heuristic”, erroneously assuming that the behavior of a stock matches the pattern of its flows. We discuss the origins of stock–flow failure and implications for management and education.     

Difficult Patients in Group Analysis: The Personification of (ba) I:A/M

Following a discussion of the treatment of difficult patients in group analysis, two theories are proposed concerning a fourth basic assumption in the unconscious life of groups, called Incohesion: Aggregation/Massification or (ba) I:A/M and the personification of basic assumption processes, in particular that of (ba) I:A/M by difficult patients. These theories are illustrated with clinical data. Special attention is given to crustacean and amoeboid forms of encapsulation as a defence against the fear of annihilation within the context of the traumatogenic process. It is suggested that for difficult patients the treatment of choice is dyadic psychotherapy/psychoanalysis followed by group analysis.     

Reaction of a Ni-coated Al nanoparticle to form B2-NiAl: A molecular dynamics study

The kinetic reaction in a Ni-coated Al nanoparticle with equi-atomic fractions and diameter of approximately 4.5 nm is studied by means of molecular dynamics simulation, using a potential of the embedded atom type to model the interatomic interactions. First, the large driving force for the alloying of Ni and Al initiates solid state amorphization of the nanoparticle with the formation of Ni₅₀Al₅₀ amorphous alloy. Amorphization makes intermixing of the components much easier compared to the crystalline state. The average rate of penetration of Ni atoms can be estimated to be about two times higher than Al atoms, whilst the total rate of inter-penetration can be estimated to be of the order of 10^?2 m/s. The heat of the intermixing with the formation of Ni₅₀Al₅₀ amorphous alloy can be estimated at approximately ?0.34 eV/at. Next, the crystallization of the Ni₅₀Al₅₀ amorphous alloy into B2-NiAl ordered crystal structure is observed. The heat of the crystallization can be estimated as approximately ?0.08 eV/at. Then, the B2-NiAl ordered nanoparticle melts at a temperature of approximately 1500 K. It is shown that, for the alloying reaction in the initial Ni-coated Al nanoparticle, the ignition temperature can be as low as approximately 200 K, while the adiabatic temperature for the reaction is below the melting temperature of the nanoparticle with the B2-NiAl ordered structure.     

Gamma- and theta-band synchronization during semantic priming reflect local and long-range lexical–semantic networks

Anterior and posterior brain areas are involved in the storage and retrieval of semantic representations, but it is not known how these areas dynamically interact during semantic processing. We hypothesized that long-range theta-band coherence would reflect coupling of these areas and examined the oscillatory dynamics of lexical–semantic processing using a semantic priming paradigm with a delayed letter-search task while recording subjects’ EEG. Time–frequency analysis revealed facilitation of semantic processing for Related compared to Unrelated conditions, which resulted in a reduced N400 and reduced gamma power from 150 to 450 ms. Moreover, we observed greater anterior–posterior theta coherence for Unrelated compared to Related conditions over the time windows 150–425 ms and 600–900 ms. We suggest that while gamma power reflects activation of local functional networks supporting semantic representations, theta coherence indicates dynamic coupling of anterior and posterior areas for retrieval and post-retrieval processing and possibly an interaction between semantic relatedness and working memory.