The pyeTribe: Simultaneous eyetracking for economic games

The recent introduction of inexpensive eyetrackers has opened up a wealth of opportunities for researchers to study attention in interactive tasks. No software package has previously been available to help researchers exploit those opportunities. We created “the pyeTribe,” a software package that offers, among others, the following features: first, a communication platform between many eyetrackers to allow for simultaneous recording of multiple participants; second, the simultaneous calibration of multiple eyetrackers without the experimenter’s supervision; third, data collection restricted to periods of interest, thus reducing the volume of data and easing analysis. We used a standard economic game (the public goods game) to examine the data quality and demonstrate the potential of our software package. Moreover, we conducted a modeling analysis, which illustrates how combining process and behavioral data can improve models of human decision-making behavior in social situations. Our software is open source.     

Social network predictors of bullying and victimization

This study examined whether bullies, victims, and aggressive victims (those who are both bullies and victims) differed on classroom social network variables, gender, and ethnicity. Survey data were collected from a primarily Latino and Asian sample of 1,368 Southern California 6th graders (mean age = 11.3 years). Logistic regression analyses were performed to determine whether network characteristics and ethnicity were associated with each of the outcome variables. Consistent with social cognitive theory, friends' participation in aggressive behaviors was positively associated with being a bully or an aggressive victim, and negatively associated with being a victim. Consistent with social dominance theory, the number of friendship nominations received was negatively associated with being a victim. Female bullies received fewer friendship nominations, but had a higher proportion of reciprocated friendships. Victims were disproportionately Asian. The findings suggest that bullying prevention efforts targeting highly aggressive students may also diffuse to their friends, and that assertiveness training in handling aggressive situations may successfully combat bullying and aggression.     

Intergroup distinctiveness and differentiation: a meta-analytic integration

The authors examined the relation between perceptions of intergroup distinctiveness and intergroup differentiation in a meta-analysis. They tested the social identity theory prediction that low intergroup distinctiveness underlies differentiation (the "reactive distinctiveness" hypothesis) for effects on behavioral and judgmental differentiation. In addition, they examined the moderating power of 4 variables that H. Tajfel and J. C. Turner (1979) predicted would influence differentiation (group identification, relevance of the dimension of comparison, relevance of the outgroup. and nature of intergroup relations). Analysis of 60 tests revealed that the overall effect of distinctiveness on differentiation was not significantly different from 0, but reactive distinctiveness was found on behavioral differentiation measures, whereas reflective distinctiveness was found on judgmental differentiation measures. Only group identification was a reliable moderator. High identifiers showed reactive distinctiveness, whereas low identifiers showed reflective distinctiveness.     

Development and validation of a Rasch-derived CES-D short form

The current study presents a Rasch-derived short form of the Center for Epidemiologic Studies-Depression scale (CES-D) for use as a depression screening tool in the general population. In contrast to short forms developed with reliance on classical measurement techniques, those developed using techniques based on item response theory produce a measure that offers true interval scaling, provide enhanced information about responders with extreme scores, and expand understanding of the underlying latent structure. Cross-validation of the Rasch-derived CES-D short form supported its utility and structural validity across samples. Tests of structural validity using latent variable modeling methodology indicated that a hierarchical, single-factor model of depression had the best fit for the original full form and the Rasch-derived short form of the CES-D. This finding challenges depression researchers and theorists to reconsider the interfactor relationships in the study and assessment of depression.     

Rats' performance on variable-interval schedules with a linear feedback loop between response rate and reinforcement rate

Three experiments investigated whether rats are sensitive to the molar properties of a variable-interval (VI) schedule with a positive relation between response rate and reinforcement rate (i.e., a VI+ schedule). In Experiment 1, rats responded faster on a variable ratio (VR) schedule than on a VI+ schedule with an equivalent feedback function. Reinforced interresponse times (IRTs) were shorter on the VR as compared to the VI+ schedule. In Experiments 2 and 3, there was no systematic difference in response rates maintained by a VI+ schedule and a VI schedule yoked in terms of reinforcement rate. This was found both when the yoking procedure was between-subject (Experiment 2) and within-subject (Experiment 3). Mean reinforced IRTs were similar on both the VI+ and yoked VI schedules, but these values were more variable on the VI+ schedule. These results provided no evidence that rats are sensitive to the feedback function relating response rate to reinforcement rate on a VI+ schedule.     

The Spanish form of the Death Depression Scale

The aims were to estimate the psychometric properties of the Spanish form of the Death Depression Scale and to compare these with those of other versions of the scale. The Death Depression Scale was administered to a sample of 218 Spanish student nurses, together with Templer's Death Anxiety Scale and measures of general depression and anxiety. The Cronbach coefficient a was 83, and a 4-wk. test-retest correlation was .87. The correlations with scores on other tests were similar to those obtained in former studies. After applying a principal components factor analysis with varimax rotation, four factors with eigenvalues greater than one were identified. These factors were labeled Death Sadness, Death Finality, Meaninglessness of Life, and Feeling of Loss. Generally speaking, the results favour consideration of the Death Depression Scale as a valid and reliable means of assessment among Spanish-speaking individuals.     

The role of effort in perceiving distance

Berkeley proposed that space is perceived in terms of effort. Consistent with his proposal, the present studies show that perceived egocentric distance increases when people are encumbered by wearing a heavy backpack or have completed a visual-motor adaptation that reduces the anticipated optic flow coinciding with walking effort. In accord with Berkeley's proposal and Gibson's theory of affordances, these studies show that the perception of spatial layout is influenced by locomotor effort.