Birth of an Abstraction: A Dynamical Systems Account of the Discovery of an Elsewhere Principle in a Category Learning Task

Human participants and recurrent (“connectionist”) neural networks were both trained on a categorization system abstractly similar to natural language systems involving irregular (“strong”) classes and a default class. Both the humans and the networks exhibited staged learning and a generalization pattern reminiscent of the Elsewhere Condition (Kiparsky, 1973). Previous connectionist accounts of related phenomena have often been vague about the nature of the networks’ encoding systems. We analyzed our network using dynamical systems theory, revealing topological and geometric properties that can be directly compared with the mechanisms of non‐connectionist, rule‐based accounts. The results reveal that the networks “contain” structures related to mechanisms posited by rule‐based models, partly vindicating the insights of these models. On the other hand, they support the one mechanism (OM), as opposed to the more than one mechanism (MOM), view of symbolic abstraction by showing how the appearance of MOM behavior can arise emergently from one underlying set of principles. The key new contribution of this study is to show that dynamical systems theory can allow us to explicitly characterize the relationship between the two perspectives in implemented models.     

A phase-field model for deformation twinning

We propose a phase-field model for modeling microstructure evolution during deformation twinning. The order parameters are proportional to the shear strains defined in terms of twin plane orientations and twinning directions. Using a face-centered cubic Al as an example, the deformation energy as a function of shear strain is obtained using first-principle calculations. The gradient energy coefficients are fitted to the twin boundary energies along the twinning planes and to the dislocation core energies along the directions that are perpendicular to the twinning planes. The elastic strain energy of a twinned structure is included using the Khachaturyan's elastic theory. We simulated the twinning process and microstructure evolution under a number of fixed deformations and predicted the twinning plane orientations and microstructures.     

Combining Explicit Timing with an Interdependent Group Contingency Program to Decrease Transition Times

ABSTRACT

A sixth-grade teacher and consultant serving as a behavioral specialist developed, implemented, and evaluated the Timely Transitions Game (TTG), a procedure designed to reduce room-to-room transition times. The TTG combined several procedures that have been shown to alter student behavior including explicit timing procedures and an interdependent, group-oriented reward program with randomly selected criteria. Five transition times were measured and recorded each day. At the end of the school day, the teacher randomly selected a transition and a criterion (seconds taken to transition). If the class completed the randomly selected transition in less time than the randomly selected criterion, they earned a letter. When students earned enough letters (e.g., the five letters that spell M-U-S-I-C), they received access to the reward (e.g., listening to music during independent seat-work). Results indicated immediate and sustained decreases in transition times following the implementation of the intervention. Although methodological concerns prevent drawing cause-and-effect conclusions, the current study shows how educators can adapt and combine empirically validated strategies and procedures to remedy presenting problems.     

Investigating the relationship between employability and self-efficacy: A cross-lagged analysis

The construct of employability has been conceptually related to self-efficacy in different ways. Employability has sometimes been regarded as an equivalent to self-efficacy, or as a distinct but related phenomenon. Since the relationship between the two phenomena has not been subjected to empirical scrutiny, the aim of the present study is to analyze whether self-efficacy and employability are two distinct but related constructs, and if they are, to investigate the direction of their relationship. The data (N = 1730) were collected through a two-wave longitudinal survey with one year between each data collection (2005 and 2006). The results of confirmatory factor analysis showed that the measures of employability and self-efficacy were distinct from one another, within and over measurement points, indicating that these are related but separate constructs. The results of latent variable cross-lagged analysis showed that employability predicted subsequent self-efficacy, even after controlling for age, gender, educational level, and regional differences. Thus, employability is not an expression of efficacy beliefs, but rather, the strengthening of employability perceptions may have beneficial effects on more general efficacy beliefs.     

Younger and older adults weigh multiple cues in a similar manner to generate judgments of learning

One’s memory for past test performance (MPT) is a key piece of information individuals use when deciding how to restudy material. We used a multi-trial recognition memory task to examine adult age differences in the influence of MPT (measured by actual Trial 1 memory accuracy and subjective confidence judgments, CJs) along with Trial 1 judgments of learning (JOLs), objective and participant-estimated recognition fluencies, and Trial 2 study time on Trial 2 JOLs. We found evidence of simultaneous and independent influences of multiple objective and subjective (i.e., metacognitive) cues on Trial 2 JOLs, and these relationships were highly similar for younger and older adults. Individual differences in Trial 1 recognition accuracy and CJs on Trial 2 JOLs indicate that individuals may vary in the degree to which they rely on each MPT cue when assessing subsequent memory confidence. Aging appears to spare the ability to access multiple cues when making JOLs.     

The bidirectional relation between positive mental health and psychopathology in a longitudinal representative panel study

Background: There is accumulating evidence that positive mental health and psychopathology should be seen as separate indicators of mental health. This study contributes to this evidence by investigating the bidirectional relation between positive mental health and psychopathological symptoms over time. Methods: Positive mental health (MHC-SF) and psychopathological symptoms (BSI) were longitudinally measured in a representative adult sample (N?=?1932) on four measurement occasions in nine months. A cross-lagged panel design was applied and evaluated with a latent growth model combined with an item response theory measurement model. Results: Psychopathological symptoms were longitudinally related to positive mental health and vice versa, controlling for initial levels. The changes over time were even more important than the absolute levels of psychopathological symptoms and positive mental health, respectively. Conclusions: The results underline the need for a comprehensive perspective on mental health, incorporating both the treatment of symptoms and the enhancement of well-being.     

Life satisfaction across adulthood: different determinants at different ages?

It is likely that with aging and changing life circumstances, individuals’ values shift in systematic ways, and that these shifts may be accompanied by shifts in the determinants of their subjective judgments of well being. To examine this possibility, the relations among the Satisfaction With Life Scale (SWLS) and a number of personality, affect, demographic, and cognitive variables were examined in a sample of 818 participants between the ages of 18 and 94. The results indicated that although many variables had significant zero-order correlations with the SWLS, only a few variables had unique utility in predicting life satisfaction. Invariance analyses indicated that while the qualitative nature of life satisfaction remains constant across adult age, the influence of fluid intelligence on judgments of life satisfaction declines with age. In contrast, negative affect is negatively associated with life satisfaction consistently across the adult age span.     

A simplicity principle in unsupervised human categorization

We address the problem of predicting how people will spontaneously divide into groups a set of novel items. This is a process akin to perceptual organization. We therefore employ the simplicity principle from perceptual organization to propose a simplicity model of unconstrained spontaneous grouping. The simplicity model predicts that people would prefer the categories for a set of novel items that provide the simplest encoding of these items. Classification predictions are derived from the model without information either about the number of categories sought or information about the distributional properties of the objects to be classified. These features of the simplicity model distinguish it from other models in unsupervised categorization (where, for example, the number of categories sought is determined via a free parameter), and we discuss how these computational differences are related to differences in modeling objectives. The predictions of the simplicity model are validated in four experiments. We also discuss the significance of simplicity in cognitive modeling more generally.     

管理胜任力特征分析:结构方程模型检验

管理胜任力特征分析是人事选拔与评价的重要内容之一。本研究在运用基于胜任力的职位分析并总结国内外有关文献的基础上,编制了管理综合素质评价量表,并运用此量表调查了220名中高层管理者,采用因素分析和结构方程模型检验企业高级管理者胜任力特征的结构。结果表明,管理胜任力特征结构由管理素质和管理技能等两个维度构成,但在维度要素及其关键度上,职位层次间存在显著差异。本研究为管理职位的测评选拔提供了新的理论依据。