Narcissism and prosocial behavior

There are many motivations for prosocial behavior, some more altruistic and some more egoistic. We posit that more narcissistic people may perform prosocial acts strategically, for example, to improve their reputations or to receive something in return

Improved ability of biological and previous caries multimarkers to predict caries disease as revealed by multivariate PLS modelling

<p>Abstract</p> <p>Background</p> <p>Dental caries is a chronic disease with plaque bacteria, diet and saliva modifying disease activity. Here we have used the PLS method to evaluate a multiplicity of such biological variables (n = 88) for ability to predict caries in a cross-sectional (baseline caries) and prospective (2-year caries development) setting.</p> <p>Methods</p> <p>Multivariate PLS modelling was used to associate the many biological variables with caries recorded in thirty 14-year-old children by measuring the numbers of incipient and manifest caries lesions at all surfaces.</p> <p>Results</p> <p>A wide but shallow gliding scale of one fifth caries promoting or protecting, and four fifths non-influential, variables occurred. The influential markers behaved in the order of plaque bacteria > diet > saliva, with previously known plaque bacteria/diet markers and a set of new protective diet markers. A differential variable patterning appeared for new versus progressing lesions. The influential biological multimarkers (n = 18) predicted baseline caries better (ROC area 0.96) than five markers (0.92) and a single lactobacilli marker (0.7) with sensitivity/specificity of 1.87, 1.78 and 1.13 at 1/3 of the subjects diagnosed sick, respectively. Moreover, biological multimarkers (n = 18) explained 2-year caries increment slightly better than reported before but predicted it poorly (ROC area 0.76). By contrast, multimarkers based on previous caries predicted alone (ROC area 0.88), or together with biological multimarkers (0.94), increment well with a sensitivity/specificity of 1.74 at 1/3 of the subjects diagnosed sick.</p> <p>Conclusion</p> <p>Multimarkers behave better than single-to-five markers but future multimarker strategies will require systematic searches for improved saliva and plaque bacteria markers.</p

Influence of Rhythmic Grouping on Duration Perception: A Novel Auditory Illusion

This study investigated a potential auditory illusion in duration perception induced by rhythmic temporal contexts. Listeners with or without musical training performed a duration discrimination task for a silent period in a rhythmic auditory sequence. The critical temporal interval was presented either within a perceptual group or between two perceptual groups. We report the just-noticeable difference (difference limen, DL) for temporal intervals and the point of subjective equality (PSE) derived from individual psychometric functions based on performance of a two-alternative forced choice task. In musically untrained individuals, equal temporal intervals were perceived as significantly longer when presented between perceptual groups than within a perceptual group (109.25% versus 102.5% of the standard duration). Only the perceived duration of the between-group interval was significantly longer than its objective duration. Musically trained individuals did not show this effect. However, in both musically trained and untrained individuals, the relative difference limens for discriminating the comparison interval from the standard interval were larger in the between-groups condition than in the within-group condition (7.3% vs. 5.6% of the standard duration). Thus, rhythmic grouping affected sensitivity to duration changes in all listeners, with duration differences being harder to detect at boundaries of rhythm groups than within rhythm groups. Our results show for the first time that temporal Gestalt induces auditory duration illusions in typical listeners, but that musical experts are not susceptible to this effect of rhythmic grouping.Ellison Medical FoundationNational Science Foundation (U.S.) (PA00P1_131448/1)McGovern Institute for Brain Research at MI