Finite Mixtures for Simultaneously Modeling Differential Effects and Nonnormal Distributions

Regression mixture models have been increasingly applied in the social and behavioral sciences as a method for identifying differential effects of predictors on outcomes. Although the typical specification of this approach is sensitive to violations of distributional assumptions, alternative methods for capturing the number of differential effects have been shown to be robust. Yet, there is still a need to better describe differential effects that exist when using regression mixture models. This study tests a new approach that uses sets of classes (called differential effects sets) to simultaneously model differential effects and account for nonnormal error distributions. Monte Carlo simulations are used to examine the performance of the approach. The number of classes needed to represent departures from normality is shown to be dependent on the degree of skew. The use of differential effects sets reduced bias in parameter estimates. Applied analyses demonstrated the implementation of the approach for describing differential effects of parental health problems on adolescent body mass index using differential effects sets approach. Findings support the usefulness of the approach, which overcomes the limitations of previous approaches for handling nonnormal errors.     

Deference as a normative power

Much of the literature on practical authority concerns the authority of the state over its subjects—authority to which we are, as G. E. M. Anscombe says, subject “willy nilly”. Yet many of our “willy” (or voluntary) relationships also seem to involve the exercise of practical authority, and this species of authority is in some ways even more puzzling than authority willy nilly. In this paper I argue that voluntary authority relies on a form of voluntary obligation that is akin (in some respects) to the kind of obligation one undertakes in making a promise. Voluntary authority depends, that is, on the possibility of taking on certain obligations more or less at will. It is generated through an interpersonal transaction that involves a directed act of deference, on one side, paired with appropriate uptake of that deference, on the other. Deference, in the relevant sense, should be understood as a normative power that is exercised when agents transfer deliberative discretion to others, undertaking directed obligations to treat others’ directives as content-independent and peremptory reasons. Voluntary authority, thus understood, is both grounded in and constrained by the equal moral authority or autonomy of the participants, since only autonomous agents have the standing to defer in a normatively significant way.     

Effects of tailoring ingredients in auditory persuasive health messages on fruit and vegetable intake

Objective: Health messages can be tailored by applying different tailoring ingredients, among which personalisation, feedback and adaptation. This experiment investigated the separate effects of these tailoring ingredients on behaviour in auditory health persuasion. Furthermore, the moderating effect of self-efficacy was assessed.

Design: The between-participants design consisted of four conditions. A generic health message served as a control condition; personalisation was applied using the recipient’s first name, feedback was given on the personal state, or the message was adapted to the recipient’s value.

Main outcome measures: The study consisted of a pre-test questionnaire (measuring fruit and vegetable intake and perceived difficulty of performing these behaviours, indicating self-efficacy), exposure to the auditory message and a follow-up questionnaire measuring fruit and vegetable intake two weeks after message exposure (n = 112).

Results: ANCOVAs showed no main effect of condition on either fruit or vegetable intake, but a moderation was found on vegetable intake: When self-efficacy was low, vegetable intake was higher after listening to the personalisation message. No significant differences between the conditions were found when self-efficacy was high.

Conclusion: Individuals with low self-efficacy seemed to benefit from incorporating personalisation, but only regarding vegetable consumption. This finding warrants further investigation in tailoring research.     

Look,no hands: A perceptual task shows that number magnitude induces shifts of attention

The mental representation of numbers along a line oriented left to right affects spatial cognition, facilitating responses in the ipsilateral hemispace (the spatial-numerical association of response codes [SNARC] effect). We investigated whether the number/space association is the result of an attentional shift or response selection. Previous research has often introduced covert left/right response cues by presenting targets to the left or the right. The present study avoided left/right cues by requiring forced choice upper/lower luminance discriminations to two mirror-reversed luminance gradients (the grayscale task). The grayscale stimuli were overlaid with strings of (1) low numbers, (2) high numbers, and (3) nonnumerical characters. In Experiment 1, 20 dextrals judged the number’s magnitude and then indicated whether the upper/lower grayscale was darker. Results showed leftward and rightward attentional biases for low and high numbers, respectively. Demands to process numbers along a left/right line were made less explicit in Experiment 2 (N=8 dextrals), using (1) a parity judgment and (2) arbitrary linguistic labels for top/bottom. Once again, a spatial congruency effect was observed. Because the response (up/down) was orthogonal to the dimension of interest (left/right), the effect of number cannot be attributed to late-stage response congruencies. This study required unspeeded responses to stimuli presented in free vision, whereas other experiments have used speeded responses. Understanding the time course of number-space effects may, therefore, be important to the debate associated with response selection.     

Visual context modulates potentiation of grasp types during semantic object categorization

Substantial evidence suggests that conceptual processing of manipulable objects is associated with potentiation of action. Such data have been viewed as evidence that objects are recognized via access to action features. Many objects, however, are associated with multiple actions. For example, a kitchen timer may be clenched with a power grip to move it but pinched with a precision grip to use it. The present study tested the hypothesis that action evocation during conceptual object processing is responsive to the visual scene in which objects are presented. Twenty-five healthy adults were asked to categorize object pictures presented in different naturalistic visual contexts that evoke either move- or use-related actions. Categorization judgments (natural vs. artifact) were performed by executing a move- or use-related action (clench vs. pinch) on a response device, and response times were assessed as a function of contextual congruence. Although the actions performed were irrelevant to the categorization judgment, responses were significantly faster when actions were compatible with the visual context. This compatibility effect was largely driven by faster pinch responses when objects were presented in use-compatible, as compared with move-compatible, contexts. The present study is the first to highlight the influence of visual scene on stimulus–response compatibility effects during semantic object processing. These data support the hypothesis that action evocation during conceptual object processing is biased toward context-relevant actions.     

Australian Trans Men: Development,Sexuality, and Mental Health

The aim of the study reported in this article was to gain an understanding of the experiences, developmental trajectories, and mental health status of Australian trans men. Participants were 279 trans men. The majority preferred to identify as “male”; from an early age, they had experienced their gender identity as different from that normatively expected of their natally assigned sex and had undertaken practices so as to facilitate their presentation as male in accordance with their gender identity. A majority reported a diagnosis of depression or anxiety within the last 12 months and attributed suicidal ideation and self‐harm and attempted suicide to personal issues with gender identity. Going through a masculinisation process and coming out reportedly led to improved mental health. The findings highlight the need to educate mental health and health care professionals on trans issues.     

Resilience to discrimination stress across ethnic identity stages of development

Ethnic identity development may increase resilience to discrimination and prejudice, which are often common and stressful for ethnic minority adolescents. Based on ethnic identity development theory and resilience theory, we hypothesize that under high discrimination stress, ethnic affirmation and ethnic identity stage will have protective moderating effects on self‐esteem and depressive symptoms. A cross‐sectional self‐report study with 125 ethnic minority adolescents (13–18 years) found that ethnic affirmation (p < .05) had protective effects on depressive symptoms (p < .05) and protective‐enhancing effects on self‐esteem at high levels of discrimination stress. Achieved ethnic identity stage (p < .05) had protective‐stabilizing effects on self‐esteem at high discrimination stress. Our findings demonstrate that the protective elements of ethnic identity are feeling positive about one's ethnic group, having learned about one's history, and having resolved conflicts about one's ethnic group.     

The effects of age and emotional valence on recognition memory: An ex‐Gaussian components analysis

The aim of this work was to study the effects of valence and age on visual image recognition memory. The International Affective Picture System (IAPS) battery was used, and response time data were analyzed using analysis of variance, as well as an ex‐Gaussian fit method. Older participants were slower and more variable in their reaction times. Response times were longer for negative valence pictures, however this was statistically significant only for young participants. This suggests that negative emotional valence has a strong effect on recognition memory in young but not in old participants. The τ parameter, often related to attention in the literature, was smaller for young than old participants in an ex‐Gaussian fit. Differences on the τ parameter might suggest poorer attentional performance in old participants.     

Context-Dependent Pathways of the Transmission of Risk from Communities to Individuals

Research has consistently documented the role of environmental risk factors in the onset of delinquent behavior among youth. Less is known about the processes through which these contextual risks are translated to individual youth behavior. The aim of the current study is to examine the role of family risk factors in the transmission of community risk. Data was obtained from a nationally representative sample of over 30,000 middle school youth and community key informants (CKI). A multilevel, moderated mediation model was estimated with family risk as the moderator of the effect of CKI ratings of community risk on youth perceptions of risk. Results showed that when youth came from low risk families (measured by parental use of positive family management strategies), youth perceptions of risk mediated the effects of community risk on youth delinquency; however, there was no evidence of a significant mediated effect under conditions of high risk (measured by poor family management). This appears to be because youth from high-risk families perceived their neighborhoods as high-risk, regardless of actual levels of risk (as reported by CKI). This study finds that the relationship between communities and adolescent behavior is complex and interacts with the family environment.