Distance stability analysis in multidimensional scaling using the jackknife method

Stability or sensitivity analysis is an important topic in data analysis that has received little attention in the application of multidimensional scaling (MDS), for which the only available approaches are given in terms of a coordinate‐based analytical jackknife methodology. Although in MDS the prime interest is in assessing the stability of the points in the configuration, this methodology may be influenced by imprecisions resulting from the inherently necessary Procrustes method. This paper proposes an analytical distance‐based jackknife procedure to study stability and cross‐validation in MDS in terms of the jackknife distances, which is not influenced by the Procrustes method. For each object, the corresponding jackknife estimated points are considered as naturally clustered points, and stability and cross‐validation are analysed in terms of the MDS distances arising from the jackknife procedure, on the basis of a weighted cluster‐MDS algorithm. A jackknife‐relevant configuration is also proposed for cross‐validation in terms of coordinates, in a cluster‐MDS framework.     

Effects of Social Norms Information and Self-Affirmation on Sugar-Sweetened Beverage Consumption Intentions and Behaviors

The separate and combined efficacy of a social norms and a self-affirmation intervention to motivate decreased sugar-sweetened beverage (SSB) consumption was examined in 2 experiments. College students were randomly assigned to receive information about SSB consumption risks, norms, both, or neither. In addition, participants performed either a self-affirmation or control task. Self-affirmation only weakly affected SSB consumption intentions and behaviors. However, participants in Experiment 2 who received risks information, norms information, or both reported greater SSB reduction intentions than did those who received no information. Two weeks later, those who received both types of information reported more frequent behavior change preparations, and it appears this effect may have been partially mediated by the changes in intentions to reduce SSB consumption.     

Emotion perception from a componential perspective

The common conceptual understanding of emotion is that they are multi-componential, including subjective feelings, appraisals, psychophysiological activation, action tendencies, and motor expressions. Emotion perception, however, has traditionally been studied in terms of emotion labels, such as “happy”, which do not clearly indicate whether one, some, or all emotion components are perceived. We examine whether emotion percepts are multi-componential and extend previous research by using more ecologically valid, dynamic, and multimodal stimuli and an alternative response measure. The results demonstrate that observers can reliably infer multiple types of information (subjective feelings, appraisals, action tendencies, and social messages) from complex emotion expressions. Furthermore, this finding appears to be robust to changes in response items. The results are discussed in light of their implications for research on emotion perception.     

Evaluative ratings and attention across the life span: emotional arousal and gender

This study was designed to investigate the evolution of emotional processing over the whole adult life span as a function of stimulus arousal and participants’ gender. To this end, self-reported affective evaluation and attentional capture prompted by pleasant and unpleasant pictures varying in arousal were measured in a large sample of participants (n?=?211) balanced by gender and equally spread across seven decades from 20 to 90 years. Results showed age differences only for affective evaluation of pleasant stimuli, with opposite patterns depending on stimulus arousal. As age increased, low-arousing pleasant cues (e.g. images of babies) were experienced as more pleasant and arousing by both males and females, whereas high-arousing stimuli (e.g. erotic images) were experienced as less pleasant only by females. In contrast, emotional pictures (both pleasant and unpleasant) were effective at capturing attention in a similar way across participants, regardless of age and gender. Taken together, these findings suggest that specific emotional cues prompt different subjective responses across different age groups, while basic mechanisms involved in attentional engagement towards both pleasant and unpleasant stimuli are preserved in healthy ageing.     

How probable is probably? It depends on whom you're talking about

Two studies tested whether people interpreted verbal chance terms in a self‐serving manner. Participants read statements describing the likelihood of events in their own future and in the future of a randomly chosen other. They interpreted the chance terms numerically. Chance terms were interpreted as denoting a higher probability when they were used to describe the likelihood of pleasant events in one's own future than when they were used to describe the likelihood of pleasant events in someone else's future (Study 1). Similarly, chance terms were interpreted as denoting a lower probability when they were used to describe the likelihood of unpleasant events in one's own future than when they were used to describe the likelihood of unpleasant events in someone else's future (Studies 1 and 2). These differences occurred primarily when the risk statements were threatening. Copyright © 2005 John Wiley & Sons, Ltd.     

THE FUTURE OF THE BUDDHIST PAST: A RESPONSE TO THE READERS

I respond to comments offered by Peter Harrison and Thupten Jinpa on my book Buddhism and Science: A Guide for the Perplexed (2008). I report briefly on the reception of the book thus far and provide a summary of its contents before responding individually to the essays of Harrison and Jinpa.     

Stress,Self‐Esteem,Hope, Optimism,and Well‐Being in Urban,Ethnic Minority Adolescents

This study examined hope, optimism, self‐esteem, social support, stress, and indices of subjective well‐being (SWB) in 137 low‐income, urban, ethnic minority adolescents. Hope, optimism, and self‐esteem were significant predictors of SWB indices, but stress predicted only 1 SWB index: negative affect. No moderators of stress and negative affect were identified. Este estudio examinó la esperanza, optimismo, autoestima, apoyo social, estrés e índices de bienestar subjetivo (SWB, por sus siglas en inglés) de 137 adolescentes urbanos de minorías étnicas y bajo nivel de ingresos. La esperanza, el optimismo y la autoestima fueron indicadores de predicción de los índices de SWB, pero el estrés predijo solamente un índice de SWB: el afecto negativo. No se identificaron moderadores del estrés y el afecto negativo.     

Environmental cue saliency influences the vividness of a remote spatial memory in rats

The Morris water maze is frequently used to evaluate the acquisition and retrieval of spatial memories. Few experiments, however, have investigated the effects of environmental cue saliency on the strength or persistence of such memories after a short vs. long post-acquisition interval. Using a Morris water maze, we therefore tested in rats the effect of the saliency of distal cues on the vividness of a recent (5 days) vs. remote (25 days) memory. Rats trained in a cue-enriched vs. a cue-impoverished context showed a better overall level of performance during acquisition. Furthermore, the probe trials revealed that the rats trained and tested in the cue-impoverished context (1) spent less time in the target quadrant at the 25-day delay, and (2) swam shorter distances in the target area, with fewer crossings at both 5- and 25-day delays, as compared to their counterparts trained and tested in the cue-enriched context. Thus, the memory trace formed in the cue-enriched context shows better resistance to time, suggesting an implication of cue saliency in the vividness of a spatial memory.     

Adjustment problems in the family and school contexts, attitude towards authority, and violent behavior at school in adolescence

This study analyzed the role of different but interrelated variables in the family and school contexts in relation to problems of violent behavior at school during adolescence. Participants were 1,068 students aged 11 to 16 (47% male) drawn from secondary schools in the Valencian Community (Spain). Statistical analyses were carried out using structural equation modeling. The model accounted for 32% of the variance in school violence. Results showed a direct association between quality of communication with father and teacher's expectations of the student with the adolescent's involvement in violent behavior at school. Moreover, findings showed indirect paths by which adolescents' self-concept (family and school domains), acceptance by peers, and attitude toward authority, seemed to be influenced by the quality of interactions with parent and teachers, and also were closely associated with violent behavior at school. Findings are discussed in relation to previous research on adolescent psychosocial adjustment and behavioral problems at school.