Tactile order memory: evidence for sequence learning phenomena found with other stimulus types

We examine serial order memory for sequences of tactile stimuli and investigate whether established characteristics of order memory, namely serial position effects, error distributions, and Hebb repetition learning, are observed with tactile memory. Visually obscured participants received six tactile stimulations: one to each of six fingers. At test, participants lifted the six fingers in the order of stimulation. For every third trial participants received the same order of stimulation (i.e. the Hebb sequence). Serial recall accuracy produced the canonical bowed serial position function found for immediate serial recall. In addition, recall for the Hebb sequence improved relative to the filler sequences, providing the first demonstration of the Hebb repetition effect with tactile stimuli. Analysis of errors revealed close similarities to that reported with verbal and visual stimuli. This experiment further generalises established features of order memory to tactile memory, supporting the utilisation of an analogous order memory mechanism across stimuli.     

The cost of simplifying complex developmental phenomena: a new perspective on learning to walk

Researchers can study complex developmental phenomena with all the inherent noise and complexity or simplify behaviors to hone in on the essential aspects of a phenomenon. We used the development of walking as a model system to compare the costs and benefits of simplifying a complex, noisy behavior. Traditionally, researchers simplify infant walking by recording gait measures as infants take continuous, forward steps along straight paths. Here, we compared the traditional straight‐path task with spontaneous walking during 20 minutes of free play in 97 infants (10.75–19.99 months of age). We recorded infants’ footfalls on an instrumented floor to calculate gait measures in the straight‐path and free‐play tasks. In addition, we scored videos for other critical aspects of spontaneous walking—steps per bout, shape of walking path, and step direction. Studying infant walking during free play incurred no cost compared with the straight‐path task, but considerable benefits. Straight‐path gait was highly correlated with spontaneous gait and both sets of measures improved with walking age, validating use of the straight‐path task as an index of development. However, a large proportion of free‐play bouts were too short to permit standard gait measures, and most bouts were curved with omnidirectional steps. The high prevalence of these “non‐canonical” bouts was constant over development. We propose that a focus on spontaneous walking, the phenomenon we ostensibly wish to explain, yields important insights into the problems infants solve while learning to walk. Other areas of developmental research may also benefit from retaining the complexity of complex phenomena.     

Grounding-based formulations of legal positivism

The goal of this paper is to provide an accurate grounding-based formulation of positivism in the philosophy of law. I start off by discussing some simple formulations, based on the ideas that social facts are always either full or partial grounds of legal facts. I then raise a number of objections against these definitions: the full grounding proposal rules out possibilities that are compatible with positivism; the partial grounding proposal fails, on its own, to vindicate the distinctive role that is played by social facts within positivist accounts of law. Then, I present a more adequate and insightful formulation capable of solving their problems, which crucially relies on a robust notion of a social enabler. Finally, I model inclusive and exclusive positivism on the resulting template, and set out the advantages of the ground-enablers proposal.

     

数学文化与儿童数学认知

数学文化以文化为视角.在人类文化发展的历史过程中审视和理解数学,为我们认识和理解儿童数学认知开辟了全新的方向.作为数学文化的重要内容的数学信念、数学价值观、数学典故、数学符号、数学法则以及实物工具等,在儿童数学认知的知识提取、理解与表征、记忆与策略、认知风格、情绪态度以及自我效能等方面起着重要的影响作用.     

Functional classification of obsessive-compulsive phenomena

A classification of obsessive-compulsive phenomena based on the functional definition of obsessions as anxiety/discomfort producing and compulsions as anxiety/discomfort reducing is proposed. Based on the assumption of a functional equivalence between external and internal obsessive-compulsive behavior, four essential obsessive-compulsive forms are derived: (1) obssesions, (2) obsessions plus successful compulsions (anxiety/discomfort reducing), (3) obsessions plus obsessionalized compulsions (anxiety increasing), and (4) rituals consisting mainly of stereotyped, overt or covert behaviors (autonomous of anxiety/discomfort and/or obsessions). In addition, it is hypothesized that forms 1–4 represent developmental stages in the progress of obsessive-compulsive symptomatology, increasing in the order specified in complexity and severity and having varying prognostic implications. Finally, an attempt is made to suggest stage-specific behavioral treatment strategies.