The role of multiple-exemplar training and naming in establishing derived equivalence in an infant

The conditions under which symmetry and equivalence relations develop are still controversial. This paper reports three experiments that attempt to analyze the impact of multiple-exemplar training (MET) in receptive symmetry on the emergence of visual-visual equivalence relations with a very young child, Gloria. At the age of 15 months 24 days (15m24d), Gloria was tested for receptive symmetry and naming and showed no evidence of either repertoire. In the first experiment, MET in immediate and delayed receptive symmetrical responding or listener behavior (from object-sound to immediate and delayed sound-object selection) proceeded for one month with 10 different objects. This was followed, at 16m25d, by a second test conducted with six new objects. Gloria showed generalized receptive symmetry with a 3-hr delay; however no evidence of naming with new objects was found. Experiment 2 began at 17m with the aim of establishing derived visual-visual equivalence relations using a matching-to-sample format with two comparisons. Visual-visual equivalence responding emerged at 19m, although Gloria still had not shown evidence of naming. Experiment 3 (22m to 23m25d) used a three-comparison matching-to-sample procedure to establish visual-visual equivalence. Equivalence responding emerged as in Experiment 2, and naming emerged by the end of Experiment 3. Results are discussed in terms of the history of training in bidirectional relations responsible for the emergence of visual-visual equivalence relations and of their implications for current theories of stimulus equivalence.     

Depression and cocaine dependence

Presence of depression in cocaine-dependent users is relevant for treatment of these persons. This study assessed the presence of depressive symptomatology with a published Spanish translation of the Beck Depression Inventory for a sample of 115 Spanish cocaine-dependent users who were in outpatient treatment at Centers of Drug Dependence of Galicia, Spain. The mean score was 13.7 (SD = 10.3), with 24.3% of the sample having scores which indicate clinical depression (cut off > or =21). These data underscore the need to assess the presence of depression in cocaine-dependent users who require treatment.     

Working memory deficits in transgenic rats overexpressing human adenosine A2A receptors in the brain

Adenosine receptors in the central nervous system have been implicated in the modulation of different behavioural patterns and cognitive functions although the specific role of A(2A) receptor (A(2A)R) subtype in learning and memory is still unclear. In the present work we establish a novel transgenic rat strain, TGR(NSEhA2A), overexpressing adenosine A(2A)Rs mainly in the cerebral cortex, the hippocampal formation, and the cerebellum. Thereafter, we explore the relevance of this A(2A)Rs overexpression for learning and memory function. Animals were behaviourally assessed in several learning and memory tasks (6-arms radial tunnel maze, T-maze, object recognition, and several Morris water maze paradigms) and other tests for spontaneous motor activity (open field, hexagonal tunnel maze) and anxiety (plus maze) as modification of these behaviours may interfere with the assessment of cognitive function. Neither motor performance and emotional/anxious-like behaviours were altered by overexpression of A(2A)Rs. TGR(NSEhA2A) showed normal hippocampal-dependent learning of spatial reference memory. However, they presented working memory deficits as detected by performance of constant errors in the blind arms of the 6 arm radial tunnel maze, reduced recognition of a novel object and a lack of learning improvement over four trials on the same day which was not observed over consecutive days in a repeated acquisition paradigm in the Morris water maze. Given the interdependence between adenosinic and dopaminergic function, the present results render the novel TGR(NSEhA2A) as a putative animal model for the working memory deficits and cognitive disruptions related to overstimulation of cortical A(2A)Rs or to dopaminergic prefrontal dysfunction as seen in schizophrenic or Parkinson's disease patients.     

Cholinergic afferents to the locus coeruleus and noradrenergic afferents to the medial septum mediate LTP-reinforcement in the dentate gyrus by stimulation of the amygdala

Transient long-term potentiation (E-LTP) can be transformed into a long-lasting LTP (L-LTP) in the dentate gyrus (DG) by behavioral stimuli with high motivational content. Previous research from our group has identified several brain structures, such as the basolateral amygdala (BLA), the locus coeruleus (LC), the medial septum (MS) and transmitters as noradrenaline (NA) and acetylcholine (ACh) that are involved in these processes. Here we have investigated the functional interplay among brain structures and systems which result in the conversion of a E-LTP into a L-LTP (reinforcement) by stimulation of the BLA (BLA-R). We used topical application of specific drugs into DG, and other targets, while following the time course of LTP induced by stimulation of the perforant pathway (PP) to study their specific contribution to BLA-R. One injection cannula, a recording electrode in the DG and stimulating electrodes in the PP and the BLA were stereotactically implanted one week before electrophysiological experiments. Topical application of atropine or propranolol into the DG blocked BLA-R in both cases, but the effect of propranolol occurred earlier, suggesting a role of NA within the DG during an intermediate stage of LTP maintenance. The injection of lidocaine into the LC abolished BLA-R indicating that the LC is part of the functional neural reinforcing system. The effect on the LC is mediated by cholinergic afferents because application of atropine into the LC produced the same effect. Injection of lidocaine inactivating the MS also abolished BLA-R. This effect was mediated by noradrenergic afferents (probably from the LC) because the application of propranolol into the MS prevented BLA-R. These findings suggest a functional loop for BLA-R involving cholinergic afferents to the LC, a noradrenergic projection from the LC to the DG and the MS, and finally, the cholinergic projection from the MS to the DG.     

Factor structure of the Perceived Stress Scale (PSS) in a sample from Mexico

The aim of this study was to analyze the cultural adaptation of the European Spanish version of the Perceived Stress Scale (PSS; Cohen, Kamarak, & Mermelstein, 1983), for its use in Mexican samples. Using a random sample of students, internal consistency was analyzed and the factor structure of the Spanish version of the PSS was compared with the factor structure found in the English version. Internal consistency was adequate (alpha = .83) and confirmatory factor analysis corroborated the factor structure. Factor 1 explained 42.8% of the variance and Factor 2 accounted for 53.2%. The goodness-of-fit measures also revealed an adequate fit. The cultural adaptation of the PSS was also evaluated with satisfactory results.     

Underlying dimensions of ecocentric and anthropocentric environmental beliefs

This study focuses on the cognitive components of general environmental attitudes. Taking as a starting point the scale of Thompson and Barton (1994) to identify ecocentric and anthropocentric motives in environmental conservation, the beliefs that guide attitudes in the person-environment relationship are analyzed. Confirmatory factor analysis was used to contrast the tripartite structure of these beliefs--based on egoistic, socioaltruistic, and biospheric aspects-with a two-dimensional structure that confronts ecocentric and anthropocentric orientations. The results obtained from two samples, a student sample (n = 212) and a sample from the general population of Madrid (n = 205), indicate the existence of a three-dimensional structure of environmental beliefs: an anthropocentric dimension based on the instrumental value of the environment for human beings, a biospheric dimension that values the environment for its own sake, and, lastly, an egobiocentric dimension that values the human being within nature as a whole.     

The effect of the model's presence and of negative evidence on infants' selective imitation

This study demonstrated selective “rational” imitation in infants in two testing conditions: in the presence or absence of the model during the response phase. In the study, 14-month-olds were more likely to imitate a tool-use behavior when a prior failed attempt emphasized the logical reason and relevance of introducing this novel means, making it cognitively transparent for the infants. Infants also learned imitatively from the cognitively opaque (yet socially communicated) modeling situation, but to a lesser degree. Furthermore, the presence of the model as a social partner during testing influenced the performance of infants in that they were more likely to imitate the novel means when the model was present during testing. These results highlight the important interaction of interpretive schemas (e.g., causality, teleological stance) and social communicative cues in action interpretation guiding imitative learning.     

Digital Photography and Picture Sharing: Redefining the Public/Private Divide

Digital photography is contributing to the renegotiation of the public and private divide and to the transformation of privacy and intimacy, especially with the convergence of digital cameras, mobile phones, and web sites. This convergence contributes to the redefinition of public and private and to the transformation of their boundaries, which have always been subject to historical and geographical change. Taking pictures or filming videos of strangers in public places and showing them in webs like Flickr or YouTube, or making self-portraits available to strangers in instant messenger, social network sites, or photo blogs are becoming a current practice for a growing number of Internet users. Both are examples of the intertwining of online and offline practices, experiences, and meanings that challenge the traditional concepts of the public and the private. Uses of digital images play a role in the way people perform being a stranger and in the way they relate to strangers, online and offline. The mere claims about the privatization of the public space or the public disclosure of intimacy do not account for all these practices, situations, and attitudes, as they are not a simple translation of behaviors and codes from one realm to the other.     

Worry in Adults and Children: Developmental Differences in the Importance of Probability and Cost Judgments

This study investigated developmental differences in the relationship of probability and cost estimates to worrying. Adults, younger children (M age = 8.67 years) and older children (M age = 11.06 years) rated the extent to which they worry about a list of negative social and physical outcomes and provided subjective probability and cost estimates for the same outcomes. Adults reported worrying more about social outcomes and rated them as less ‘bad’ (or costly) but more likely to occur than physical outcomes. Unlike adults, children in both age groups reported worrying more about physical outcomes. However, similar to adults, they also rated social outcomes as less ‘bad’ but more likely to occur than physical outcomes. Regression analyses showed that probability ratings were the best predictors of worry in adults, both probability and cost ratings equally predicted worry in older children, but only cost ratings predicted worry in younger children.