Twelve-month-olds point to share attention and interest

Infants point for various motives. Classically, one such motive is declarative, to share attention and interest with adults to events. Recently, some researchers have questioned whether infants have this motivation. In the current study, an adult reacted to 12-month-olds' pointing in different ways, and infants' responses were observed. Results showed that when the adult shared attention and interest (i.e alternated gaze and emoted), infants pointed more frequently across trials and tended to prolong each point--presumably to prolong the satisfying interaction. However, when the adult emoted to the infant alone or looked only to the event, infants pointed less across trials and repeated points more within trials--presumably in an attempt to establish joint attention. Results suggest that 12-month-olds point declaratively and understand that others have psychological states that can be directed and shared.     

Olympic medals as fruits of comparison? Assimilation and contrast in sequential performance judgments

The authors investigated the evaluative consequences of sequential performance judgments. Recent social comparison research has suggested that performance judgments may be influenced by judgments about a preceding performance. Specifically, performance judgments may be assimilated to judgments of the preceding performance if judges focus on similarities between the two. If judges focus on differences, however, contrast may ensue. The authors examined sequential performance judgments, using data gathered from the 2004 Olympic Games as well as data gathered in the laboratory with students or experienced gymnastics judges as participants. Sequential performance judgments were influenced by previously judged performances, and the direction of this influence depended on the degree of perceived similarity between the successive performances.     

Wundt as chemist? A fresh look at his practice and theory of experimentation

Mid-19th-century chemistry constituted a practically and theoretically important resource for experimental psychology as conceived by Wilhelm Wundt (1832-1920). In the early 1850s, Wundt began working in Gustav Herth's private chemical laboratory in Heidelberg. The experimental work Wundt conducted under Herth's direction provided the practical model for the psychological methods advocated in Wundt's pioneering publication on visual perception in 1862. With respect to theory, Wundt relied on John Stuart Mill's System of Logic, a book often referring to the chemical writings by Justus Liebig. Wundt not only read and quoted Mill's logic but also was personally acquainted with its German translator, the former Liebig student Jacob Schiel. Thus, in various ways, chemistry influenced Wundt's early theory and practice of experiment.     

Intra-individual variability in task performance after cognitive training is associated with long-term outcomes in children

The potential benefits and mechanistic effects of working memory training (WMT) in children are the subject of much research and debate. We show that after five weeks of school-based, adaptive WMT 6–9 year-old primary school children had greater activity in prefrontal and striatal brain regions, higher task accuracy, and reduced intra-individual variability in response times compared to controls. Using a sequential sampling decision model, we demonstrate that this reduction in intra-individual variability can be explained by changes to the evidence accumulation rates and thresholds. Critically, intra-individual variability is useful in quantifying the immediate impact of cognitive training interventions, being a better predictor of academic skills and well-being 6–12 months after the end of training than task accuracy. Taken together, our results suggest that attention control is the initial mechanism that leads to the long-run benefits from adaptive WMT. Selective and sustained attention abilities may serve as a scaffold for subsequent changes in higher cognitive processes, academic skills, and general well-being. Furthermore, these results highlight that the selection of outcome measures and the timing of the assessments play a crucial role in detecting training efficacy. Thus, evaluating intra-individual variability, during or directly after training could allow for the early tailoring of training interventions in terms of duration or content to maximise their impact.     

Differential effects of personality traits related to the P-ImpUSS dimension on latent inhibition in healthy female subjects

An experiment was performed to investigate the effects of various personality traits (psychoticism, impulsiveness, sensation seeking) with substantial loadings on the P-ImpUSS dimension on latent inhibition (LI). LI refers to the finding that performance on a learning task is poorer for a preexposed irrelevant stimulus than for a novel stimulus. Forty-eight female subjects were tested by a rule-learning task that has been shown to reliably produce differential LI effects in low and high psychosis-prone normals. Results suggest that, besides psychoticism, the sensation seeking subfactor disinhibition is negatively associated with LI. Furthermore, stepwise regression analysis revealed that combining individual psychoticism and disinhibition scores results in a significant increase in explained variance of LI. These findings are discussed in terms of a relationship between distinct P-ImpUSS-related aspects of personality and LI.     

The influence of practice on the development of motor skills in pianists: a longitudinal study in a selected motor task

A longitudinal study was conducted to investigate the influence of practice on the long-term development of expert pianists' motor skills in a relevant musical context. Temporal evenness in standardized scale playing was assessed twice in 19 pianists within an average time interval of 27 months. Questionnaires were used for retrospective assessment of practice quantity and several qualitative parameters related to practicing of scales. The development of temporal evenness in scale playing over the follow-up period correlated with the practice time accumulated during that period and with the average daily practice time. Expert pianists with an average daily practice time of 3.75h or more showed an improvement of performance in this selected motor skill. No significant association was observed between motor skill development during the follow-up period and the content of practice. Stepwise linear regression revealed a model predicting 43% of the variance of motor skill development, with practice time accumulated during the follow-up period as the only predictor. It was concluded that, in expert pianists, maintenance of motor skills in the selected motor task was strongly influenced by practice quantity.     

Executable specifications for hypothesis-based reasoning with Prolog and Constraint Handling Rules

Constraint Handling Rules (CHR) is an extension to Prolog which opens up a spectrum of hypothesis-based reasoning in logic programs without additional interpretation overhead. Abduction with integrity constraints is one example of hypothesis-based reasoning which can be implemented directly in Prolog and CHR with a straightforward use of available and efficiently implemented facilities.The present paper clarifies the semantic foundations for this way of doing abduction in CHR and Prolog as well as other examples of hypothesis-based reasoning that is possible, including assumptive logic programming, hypotheses with priority and scope, and nonmonotonic reasoning.Examples are presented as executable code so the paper may also serve the additional purpose of a practical guide for developing such programs, and it is demonstrated that the approach provides a seamless integration with existing constraint solvers.