Association between polymorphisms in the dopamine transporter gene and depression: evidence for a gene-environment interaction in a sample of juvenile detainees

Previous research has generated examples of how genetic and environmental factors can interact to create risk for psychopathology. Using a gene-by-environment (G x E) interaction design, we tested whether three polymorphisms in the dopamine transporter gene (DAT1, also referred to as SLC6A3, located at 5p15.33) interacted with maternal parenting style to predict first-onset episodes of depression. Participants were male adolescents (N= 176) recruited from a juvenile detention center in northern Russia. As hypothesized, one of the polymorphisms (rs40184) moderated the effect of perceived maternal rejection on the onset of major depressive disorder, as well as on suicidal ideation. Further, this G x E interaction was specific to depression; it did not predict clinically significant anxiety. These results highlight the need for further research investigating the moderating effects of dopaminergic genes on depression.     

Grounding compositional symbols: no composition without discrimination

The classical computational conception of meaning has been challenged by the idea that symbols must be grounded on sensorimotor processes. A difficult question arises from the fact that grounding representations cannot be symbolic themselves but, in order to support compositionality, should work as primitives. This implies that they should be precisely identifiable and strictly connected with discriminable perceptual features. Ideally, each representation should correspond to a single discriminable feature. The present study was aimed at exploring whether feature discrimination is a fundamental requisite for grounding compositional symbols. We studied this problem by using Integral stimuli, composed of two interacting and not separable features. Such stimuli were selected in Experiment 1 as pictures whose component features are easily or barely discriminable (Separable or Integral) on the basis of psychological distance metrics (City-block or Euclidean) computed from similarity judgments. In Experiment 2, either each feature was associated with one word of a two-word expression, or the whole stimulus with a single word. In Experiment 3, the procedure was reversed and words or expressions were associated with whole pictures or separate features. Results support the hypothesis that single words are best grounded by Integral stimuli and composite expressions by Separable stimuli, where a strict association of single words with discriminated features is possible.     

The development of abstract syntax: Evidence from structural priming and the lexical boost

Structural priming paradigms have been influential in shaping theories of adult sentence processing and theories of syntactic development. However, until recently there have been few attempts to provide an integrated account that explains both adult and developmental data. The aim of the present paper was to begin the process of integration by taking a developmental approach to structural priming. Using a dialog comprehension-to-production paradigm, we primed participants (3–4 year olds, 5–6 year olds and adults) with double object datives (Wendy gave Bob a dog) and prepositional datives (Wendy gave a dog to Bob). Half the participants heard the same verb in prime and target (e.g. gave–gave) and half heard a different verb (e.g. sent–gave). The results revealed substantial differences in the magnitude of priming across development. First, there was a small but significant abstract structural priming effect across all age groups, but this effect was larger in younger children than in older children and adults. Second, adding verb overlap between prime and target prompted a large, significant increase in the priming effect in adults (a lexical boost), a small, marginally significant increase in the older children and no increase in the youngest children. The results support the idea that abstract syntactic knowledge can develop independently of verb-specific frames. They also support the idea that different mechanisms may be needed to explain abstract structural priming and lexical priming, as predicted by the implicit learning account (Bock, K., & Griffin, Z. M. (2000). The persistence of structural priming: Transient activation or implicit learning? Journal of Experimental Psychology – General, 129(2), 177–192). Finally, the results illustrate the value of an integrative developmental approach to both theories of adult sentence processing and theories of syntax acquisition.     

Indirect majority and minority influence: An exploratory study

In a 2 × 2 design, 85 subjects were asked to estimate the size of angles (direct influence) that were either 90 or 85°, after being confronted with incorrect judgements of a majority (88 per cent) or a minority (12 per cent) of people estimating the angles at 50°. Additionally, pre- and post-test measures were used to establish indirect influence on subjects' judgements pertaining to acute angles (i.e. on the estimation of the length of lines constituting the angles, and on the imaginary weight of figures represented by these angles). Overall, little direct influence is observed. This may partly be due to the introduction of a denial of the credibility of the source in all conditions. In fact, some evidence of direct influence is only found in the majority–85° angles condition. An instance of indirect influence (on the estimation of length of lines) appeared as the result of a majority stance when the angles in the experimental phase were 90°. When these angles were 85°, indirect minority influence (on the estimation of weight of figures) was observed. These effects had been predicted on the basis of the hypothesis stating that indirect majority influence would be possible when subjects expected consensus on the correct response (in the 90° angles condition), without being able to reach consensus at the manifest level (because of the denial and the restriction imposed by the clear shape of 90° angles). Indirect minority influence was hypothesized to be stronger in a situation that allows for diverse responses (i.e. for 85° angles).     

Montreal Cognitive Assessment (MoCA) for HIV-Associated Neurocognitive Disorders

Neuropsychology Review - This study aims to systematically review the evidence on the accuracy of the Montreal Cognitive Assessment (MoCA) test for diagnosing HIV–associated neurocognitive...     

Naïve chicks do not prefer objects with stable body orientation,though they may prefer behavioural variability

Animal Cognition - Domestic chicks (Gallus gallus domesticus) have been widely used as a model to study the motion cues that allow visually naïve organisms to detect animate agents shortly...