Exaggerated NMDA mediated LTD in a mouse model of Down syndrome and pharmacological rescuing by memantine

The Ts65Dn mouse is the best-studied animal model for Down syndrome. In the experiments described here, NMDA-mediated or mGluR-mediated LTD was induced in the CA1 region of hippocampal slices from Ts65Dn and euploid control mice by bath application of 20 μM NMDA for 3 min and 50 μM DHPG for 5 min, respectively. We found that Ts65Dn mice display exaggerated NMDA-induced, but not mGluR-induced, LTD in the CA1 region of the hippocampus compared with euploid control animals. In addition, this abnormal level of LTD can be pharmacologically rescued by the NMDA receptor antagonist memantine.     

More than Data Collectors: A Systematic Review of the Environmental Outcomes of Youth Inquiry Approaches in the United States

Over the last twenty years, research on the impact of engaging children and adolescents in the generation of new knowledge about their lives, schools, and communities, has grown tremendously. This systematic review summarizes the findings from empirical studies of youth inquiry approaches in the United States, with a focus on their environmental outcomes. Searches of four interdisciplinary databases retrieved a total of 3,724 relevant articles published between 1995 and 2015. Sixty‐three distinct studies met the systematic review inclusion criteria, of which, 36 (57.1%) reported that the youth inquiry approach contributed to positive changes among adults, peers, organizations, and/or institutions. These environmental outcomes were qualitatively recorded, inductively categorized, and then organized into Bronfenbrenner's ecological framework. Youth inquiry approaches led to practitioner growth and changes in peer group norms at the micro‐system level, program development or improvement and research benefits at the meso‐system level, and school, city, and state level policy adoption at the exo‐system level. Qualitative methods, especially case studies, were most commonly used to evaluate the impact of youth inquiry approaches on environmental outcomes. Studies of approaches that utilized advocacy to create change, targeted decision‐makers as the audience for the youth's work and convened for a longer duration were more likely to report improved environmental outcomes. This systematic review suggests that youth inquiry approaches are a promising strategy for ecological systems change.     

Idea habitats: how the prevalence of environmental cues influences the success of ideas

We investigate 1 factor that influences the success of ideas or cultural representations by proposing that they have a habitat, that is, a set of environmental cues that encourages people to recall and transmit them. We test 2 hypotheses: (a) fluctuation: the success of an idea will vary over time with fluctuations in its habitat, and (b) competition: ideas with more prevalent habitats will be more successful. Four studies use subject ratings and data from newspapers to provide correlational support for our 2 hypotheses, with a negative factoid, positive rumor, catchphrases, and variants of a proverb. Three additional experimental studies manipulate the topic of actual conversations and find empirical support for our theory, with catchphrases, proverbs, and slang. The discussion examines how habitat prevalence applies to a more extensive class of ideas and suggests how habitats may influence the process by which ideas evolve.     

Physicalism and the sortalist conception of objects

Many hold an Aristotelian metaphysic of objects: fundamentally, objects fall under sortals and have persistence conditions befitting their sort. Though sometimes offered as a theory of material objects, I argue this view is in fact incompatible with physicalism. Call a ‘sortal’ a kind of object, a ‘sortal identity’ a particular’s nature specified in sortal terms, and ‘sortal properties’ properties that are determined by an object’s sortal identity, such as its persistence conditions. From here the argument runs as follows. Something is physical only if it is physically fundamental or is determined by what is physically fundamental (P1), but sortal identities and properties are neither physically fundamental (P2) nor determined by the physically fundamental (P3). I defend each premise in turn. P1 falls out of the standard conception of physicalism. Rejecting P2 is tantamount to positing Aristotelian substantial forms and formal causes—which are themselves incompatible with physicalism. I defend P3 by showing that extant solutions to “the grounding problem”—the problem of showing how (nonfundamental) sortal properties are determined by (nonsortal) physical properties—are either physicalistically unacceptable, or else physicalistically acceptable but opposed to the sortalist metaphysic.     

Authority and Natural Kind Essence

If natural kinds have microstructural essences they have them independently of rules for the application of kind terms. This suggests that what those rules are should make no difference to the essences being discoverable. I present two thought-experiments that suggest otherwise, however. Each shows an authority’s application of rules creates the appearance of there being kind essences; absent those rules, the appearance vanishes. This suggests natural kind essences are not independent of authority-sanctioned rules.     

Field dependence,sensation seeking and driving behaviour

The present study attempted to relate field dependence-independence (FDI) to accident involvement and perceived causes of accidents as well as to trace these relationships to the sensation-seeking (SS) tendency of the field-dependent driver. In addition, the concomittant effects of internal/external locus of control (IE) were studied. Subjects (N=285) filled out a questionnaire assessing their level of FDI, SS, IE, number of accidents, as well as the attributed importance of various possible causes of their last accident. The obtained results show no relationship between FDI and SS and either the number of accidents or the importance attributed to various causes of accidents. Significant relationships were, however, obtained between FDI and SS and seat-belt use and SS and speed on the highway.     

Who drives divergence? Identity signaling, outgroup dissimilarity, and the abandonment of cultural tastes

People often diverge from members of other social groups: They select cultural tastes (e.g., possessions, attitudes, or behaviors) that distinguish them from outsiders and abandon tastes when outsiders adopt them. But while divergence is pervasive, most research on the propagation of culture is based on conformity. Consequently, it is less useful in explaining why people might abandon tastes when others adopt them. The 7 studies described in this article showed that people diverge to avoid signaling undesired identities. A field study, for example, found that undergraduates stopped wearing a particular wristband when members of the "geeky" academically focused dormitory next door started wearing them. Consistent with an identity-signaling perspective, the studies further showed that people often diverge from dissimilar outgroups to avoid the costs of misidentification. Implications for social influence, identity signaling, and the popularity and diffusion of culture are discussed.     

Cognitive and Emotion‐Regulatory Mediators of the Relationship Between Behavioral Approach System Sensitivity and Nonsuicidal Self‐Injury Frequency

Nonsuicidal self‐injury (NSSI) is highly prevalent among late adolescents and predicts the onset of suicidal ideation and behavior. Although research has established an association between the behavioral approach system (BAS) and NSSI, less research has explored mechanisms underlying this relationship. The authors examined negative and positive emotion regulation patterns, as well as the BAS‐relevant cognitive style of self‐criticism, as potential mechanisms through which a hypersensitive BAS might be related to NSSI frequency. Late adolescents (N = 177) with high and moderate BAS levels completed measures of self‐criticism, positive emotion regulation, brooding, and both lifetime and last‐year frequency of NSSI. Results indicated that self‐criticism and positive emotion dampening independently mediated the relationship between BAS and last‐year frequency of NSSI. Self‐criticism also mediated the relationship between BAS and lifetime frequency of NSSI. Results suggest that cognitive and emotion‐regulatory styles may help to explain why high BAS individuals are likely to engage in NSSI.