Dogs steal in the dark

All current evidence of visual perspective taking in dogs can possibly be explained by dogs reacting to certain stimuli rather than understanding what others see. In the current study, we set up a situation in which contextual information and social cues are in conflict. A human always forbade the dog from taking a piece of food. The part of the room being illuminated was then varied, for example, either the area where the human was seated or the area where the food was located was lit. Results show that dogs steal significantly more food when it is dark compared to when it is light. While stealing forbidden food the dog’s behaviour also depends on the type of illumination in the room. Illumination around the food, but not the human, affected the dogs’ behaviour. This indicates that dogs do not take the sight of the human as a signal to avoid the food. It also cannot be explained by a low-level associative rule of avoiding illuminated food which dogs actually approach faster when they are in private. The current finding therefore raises the possibility that dogs take into account the human’s visual access to the food while making their decision to steal it.     

Repression versus sensitization in response to media violence as predictors of cognitive avoidance and vigilance

Repression and sensitization as situational modes of coping with anxiety were examined as predictors of trait measures of cognitive avoidance and vigilance. In this study, 303 undergraduates saw a violent film clip to elicit anxiety. Increases in skin conductance level (SCL) and state anxiety (STA) from baseline were measured to identify repressors (high SCL, low STA) and contrast them with sensitizers (low SCL, high STA) and genuinely low anxious individuals (low SCL, low STA). State anger was also recorded. Trait measures of vigilance and cognitive avoidance were collected 2 weeks earlier. Significant SCL × STA interactions indicated that repressors scored higher on cognitive avoidance and lower on vigilance compared to sensitizers and low anxious participants. Repressors were less likely than sensitizers to report gaze avoidance during the clip. The anger by SCL interaction was nonsignificant, suggesting that repressors and sensitizers differ specifically in the processing of anxiety rather than negative affect in general.     

Firstborns' disadvantage in kinship detection

The ability to assess genetic ties is critical to defining one's own family and, in a broader context, to understanding relationships in groups of strangers. To recognize younger siblings as such, human firstborns can rely on the perinatal association of the mother with her new baby. Later-borns, who cannot rely on such an association, will by necessity actuate alternate strategies, such as recognition of facial clues set aside by firstborns. The effects of such differential early experiences deserve consideration; the development of matching abilities may be used throughout an individual's lifetime to detect other kinship types outside the family. In simple cognitive tasks based on matching face pictures, later-borns surpassed firstborns in detecting kinship among strangers; this pattern was found in populations of different ages and in two countries. This birth-order effect contrasts with the traditional cognitive advantage of firstborns. Inclusive fitness theory explains how early life history promotes specific strategies that can, in turn, permanently enhance human performance in certain domains.     

Synaesthesia,creativity and art: What is the link?

It has been suggested that individuals with synaesthesia may show heightened creativity as a result of being able to form meaningful associations between disparate stimuli (e.g. colour, sound). In this study, a large sample (N=82) of people with various kinds of synaesthesia were given two psychometric tests of creativity (Remote Associates Test, Alternate Uses Test) and were also asked about the amount of time engaged in creative arts (visual art, music). There was a significant tendency for synaesthetes to spend more time engaged in creative arts and this was, at least in part, dependent upon the type of synaesthesia experienced. For example, synaesthetes experiencing vision from music were far more likely to play an instrument than their other synaesthetic counterparts. There was no relationship between this tendency and the psychometric measures of creativity, but synaesthetes did outperform controls on one of the two psychometric measures (Remote Associates). We conclude that the tendency for synaesthetes to be more engaged in art is likely to have a different mechanism to psychometric measures of creativity, and that there is no direct link between them. Although synaesthetes may well perform better on some measures of creativity, we suggest that synaesthetes have better bottom‐up access to certain associations, but are not necessarily better able to use them flexibly (in divergent thinking).     

Comparing dogs and great apes in their ability to visually track object transpositions

Knowing that objects continue to exist after disappearing from sight and tracking invisible object displacements are two basic elements of spatial cognition. The current study compares dogs and apes in an invisible transposition task. Food was hidden under one of two cups in full view of the subject. After that both cups were displaced, systematically varying two main factors, whether cups were crossed during displacement and whether the cups were substituted by the other cup or instead cups were moved to new locations. While the apes were successful in all conditions, the dogs had a strong preference to approach the location where they last saw the reward, especially if this location remained filled. In addition, dogs seem to have especial difficulties to track the reward when both containers crossed their path during displacement. These results confirm the substantial difference that exists between great apes and dogs with regard to mental representation abilities required to track the invisible displacements of objects.     

The elimination of de re formulas

It is shown that de re formulas are eliminable in the modal logic S5 extended with the axiom scheme x x.     

Flexible Bayesian modelling in dichotomous item response theory using mixtures of skewed item curves

Most item response theory (IRT) models for dichotomous responses are based on probit or logit link functions which assume a symmetric relationship between the probability of a correct response and the latent traits of individuals taking a test. This assumption restricts the use of those models to the case in which all items behave symmetrically. On the other hand, asymmetric models proposed in the literature impose that all the items in a test behave asymmetrically. This assumption is inappropriate for great majority of tests which are, in general, composed of both symmetric and asymmetric items. Furthermore, a straightforward extension of the existing models in the literature would require a prior selection of the items' symmetry/asymmetry status. This paper proposes a Bayesian IRT model that accounts for symmetric and asymmetric items in a flexible but parsimonious way. That is achieved by assigning a finite mixture prior to the skewness parameter, with one of the mixture components being a point mass at zero. This allows for analyses under both model selection and model averaging approaches. Asymmetric item curves are designed through the centred skew normal distribution, which has a particularly appealing parametrization in terms of parameter interpretation and computational efficiency. An efficient Markov chain Monte Carlo algorithm is proposed to perform Bayesian inference and its performance is investigated in some simulated examples. Finally, the proposed methodology is applied to a data set from a large-scale educational exam in Brazil.     

A Treatment for College Women at Risk for Bulimia: A Controlled Evaluation

Twenty-nine college women evidencing low body esteem, repeated dieting efforts, and other dysfunctional eating behaviors or attitudes were randomly assigned to group treatment or control conditions. At posttest and follow-up, participants who received the intervention reported significantly improved levels of self-esteem and body satisfaction, as well as reductions in their reliance on potentially dangerous methods of weight management compared with controls. They also reported fewer fears of negative evaluation by others and endorsed fewer stereotypes about thinness and attractiveness. Finally, participants in the treatment condition showed significantly reduced levels of perfectionism at posttest, but this change was not maintained at follow-up. Clinical implications and research recommendations are discussed.     

Relational Semantics of the Lambek Calculus Extended with Classical Propositional Logic

We show that the relational semantics of the Lambek calculus, both nonassociative and associative, is also sound and complete for its extension with classical propositional logic. Then, using filtrations, we obtain the finite model property for the nonassociative Lambek calculus extended with classical propositional logic.     

Performing gender justice: the 2005 woman-led prayer in New York

On March 18, 2005, a group of American Muslim women and men participated in a Friday prayer led by Dr. Amina Wadud, who also gave the Friday sermon. Widely publicized in various media and debated among Muslims around the world, this event was hailed as a turning point in Muslim gender discourses by the organizers and many media representatives. This article describes the prayer as a performance and argues that the organizers, participants, and media representatives all participated in the production of meaning embodied by the prayer. According to the organizers, the achievement of Qur'anic gender justice required changes in Muslim communities, and various forms of media were of vital importance for the discussion and realization of this goal. As such, the prayer was an act of symbolic significance, which despite its discursive, spatial, and temporal limitations, became much more than an act of Islamic worship.