Higher-Order Unification: A structural relation between Huet's method and the one based on explicit substitutions

We compare two different styles of Higher-Order Unification (HOU): the classical HOU algorithm of Huet for the simply typed λ-calculus and HOU based on the λσ-calculus of explicit substitutions. For doing so, first, the original Huet algorithm for the simply typed λ-calculus with names is adapted to the language of the λ-calculus in de Bruijn's notation, since this is the notation used by the λσ-calculus. Afterwards, we introduce a new structural notation called unification tree, which eases the presentation of the subgoals generated by Huet's algorithm and its behaviour. The unification tree notation will be important for the comparison between Huet's algorithm and unification in the λσ-calculus whose derivations are presented into a structure called derivation tree. We prove that there exists an important structural correspondence between Huet's HOU and the λσ-HOU method: for each (sub-)problem in the unification tree there exists a counterpart in the derivation tree. This allows us to conclude that the λσ-HOU is a generalization of Huet's algorithm and that solutions computed by the latter are always computed by the former method.     

The representational space of numerical magnitude: illusions of length

In recent years, a growing amount of evidence concerning the relationships between numerical and spatial representations has been interpreted, by and large, in favour of the mental number line hypothesis--namely, the analogue continuum where numbers are spatially represented (Dehaene, 1992; Dehaene, Piazza, Pinel, & Cohen, 2003). This numerical representation is considered the core of number meaning and, accordingly, needs to be accessed whenever numbers are semantically processed. The present study explored, by means of a length reproduction task, whether besides the activation of lateralized spatial codes, numerical processing modulates the mental representation of a horizontal spatial extension. Mis-estimations of length induced by Arabic numbers are interpreted in terms of a cognitive illusion, according to which the elaboration of magnitude information brings about an expansion or compression of the mental representation of spatial extension. These results support the hypothesis that visuo-spatial resources are involved in the representation of numerical magnitude.     

How Should We Do Nanoethics? A Network Approach for Discerning Ethical Issues in Nanotechnology

There is no agreement on how nanoethics should proceed. In this article I focus on approaches for discerning ethical issues in nanotechnology, which is as of yet one of the most difficult and urging tasks for nanoethics. I discuss and criticize two existing approaches for discerning ethical issues in nanotechnology and propose a network approach as alternative. I discuss debates in nanoethics about the desirable role of ethics in nanotechnological development and about the newness of ethical issues in nanotechnology. On basis of a critical analysis of both debates, I formulate a number of desiderata for a method for discerning ethical issues in nanotechnology and argue that the network approach that my colleagues and I have developed for ethical issues in research and development networks is also appropriate in nanotechnology.

Deliberate practice predicts performance over time in adolescent chess players and drop‐outs: A linear mixed models analysis

In this study, the longitudinal relation between deliberate practice and performance in chess was examined using a linear mixed models analysis. The practice activities and performance ratings of young elite chess players, who were either in, or had dropped out of the Dutch national chess training, were analysed since they had started playing chess seriously. The results revealed that deliberate practice (i.e. serious chess study alone and serious chess play) strongly contributed to chess performance. The influence of deliberate practice was not only observable in current performance, but also over chess players' careers. Moreover, although the drop‐outs' chess ratings developed more slowly over time, both the persistent and drop‐out chess players benefited to the same extent from investments in deliberate practice. Finally, the effect of gender on chess performance proved to be much smaller than the effect of deliberate practice. This study provides longitudinal support for the monotonic benefits assumption of deliberate practice, by showing that over chess players' careers, deliberate practice has a significant effect on performance, and to the same extent for chess players of different ultimate performance levels. The results of this study are not in line with critique raised against the deliberate practice theory that the factors deliberate practice and talent could be confounded.     

Newborns' face recognition is based on spatial frequencies below 0.5 cycles per degree

A critical question in Cognitive Science concerns how knowledge of specific domains emerges during development. Here we examined how limitations of the visual system during the first days of life may shape subsequent development of face processing abilities. By manipulating the bands of spatial frequencies of face images, we investigated what is the nature of the visual information that newborn infants rely on to perform face recognition. Newborns were able to extract from a face the visual information lying from 0 to 1 cpd (Experiment 1), but only a narrower 0-0.5 cpd spatial frequency range was successful to accomplish face recognition (Experiment 2). These results provide the first empirical support of a low spatial frequency advantage in individual face recognition at birth and suggest that early in life low-level, non-specific perceptual constraints affect the development of the face processing system.     

The Psychoanalytic Conception of Trauma in Ferenczi and the Question of Temporality

A reciprocal and ongoing interaction about theory and clinical technique developed between Freud and Ferenczi in the years from 1908 to 1933. During the course of this ongoing dialogue, the concept of psychic trauma gradually transformed. Ferenczi continued to elaborate on this issue, and concluded with his work on the interaction of trauma and fantasy. Ferenczi initially refuted Freud's early trauma theses and finally conceptualized a metapsychological reformulation of trauma, an inverse development to Freud's formulations. Ferenczi highlighted two essential concepts in the theory and technique of trauma: the processes of identification and the splitting of the ego, while he stressed the enormous role of disavowal in the dynamics of trauma. The author hopes to demonstrate how Ferenczi's contributions added to developments of the concepts of disavowal and temporality, to the recovery of traumatic memory and the modification of the classical concept of interpretations.     

Anxiety and post-traumatic stress symptoms following wisdom tooth removal

The purpose of the present study was to determine the psychological impact of wisdom teeth removal and to identify the psychological risk factors for the development of dental anxiety and post-traumatic stress symptoms. Participants were 34 consecutive elective patients referred for surgical removal of a wisdom tooth under local anesthesia. Frequency of previous distressing dental events and general traumatic life events were assessed at baseline (t1), and emotional distress (pain, state anxiety and disturbance) immediately after treatment (t2). Post-traumatic stress responses were determined three days after treatment (t3), and at four weeks follow-up (t4), while severity of dental trait anxiety was assessed at t1 and at t4. Two patients (8%) met screening criteria for Post-Traumatic Stress Disorder (PTSD) at t4. Multivariate analysis revealed that previous exposure to distressing dental events and pre-operative anxiety level predicted anxiety level at t4, accounting for 71% of the variance. Severity of pain during treatment was a significant predictor variable of PTSD symptom severity at t4 (25% explained variance). The findings underline the importance of pain-free treatments and awareness of patients' individual predisposition to anxiety or trauma-related symptoms to reduce the risk of iatrogenic psychological harm.