Friday, September 1, 2017

The estimated 79% heritability of schizophrenia is congruent with previous reports and indicates a substantial genetic risk

Heritability of schizophrenia and schizophrenia spectrum based on the nationwide Danish Twin Register. Rikke Hilker, MD, PhD. Biological Psychiatry. https://doi.org/10.1016/j.biopsych.2017.08.017

Abstract

Background: Twin studies have provided evidence that both genetic and environmental factors contribute to schizophrenia risk. Heritability estimates of schizophrenia in twin samples have varied methodologically. This study provides updated heritability estimates based on nationwide twin data and an improved statistical methodology.

Method: Combining two nationwide registers, the Danish Twin Register and the Danish Psychiatric Research Register, we identified a sample of twins born 1951-2000 (N=31,524 twin pairs). Twins were followed up until June 1st 2011. Liability threshold models adjusting for censoring with inverse probability weighting were used to estimate probandwise concordance rates and heritability of the diagnoses of schizophrenia and schizophrenia spectrum disorders.

Results: The probandwise concordance rate of schizophrenia is 33% in monozygotic (MZ) twins and 7% in dizygotic (DZ) twins. We estimated the heritability of schizophrenia to be 79%. When expanding illness outcome to include schizophrenia spectrum disorders, the heritability estimate was almost similar, 73%.

Conclusion: The key strength of this study is the application of a novel statistical method accounting for censoring in the follow-up period to a nationwide twin sample. The estimated 79% heritability of schizophrenia is congruent with previous reports and indicates a substantial genetic risk. The high genetic risk also applies to a broader phenotype of schizophrenia spectrum disorders. The low concordance rate of 33% in MZ twins demonstrates that illness vulnerability is not solely indicated by genetic factors.

Key words: Heritability schizophrenia twin study censoring concordance register

Superior Pattern Detectors Efficiently Learn, Activate, Apply, and Update Social Stereotypes

Superior Pattern Detectors Efficiently Learn, Activate, Apply, and Update Social Stereotypes. David Lick, Adam Alter and Jonathan Freeman. Journal of Experimental Psychology: General, https://doi.org/10.1037/xge0000349

Abstract: Superior cognitive abilities are generally associated with positive outcomes such as academic achievement and social mobility. Here, we explore the darker side of cognitive ability, highlighting robust links between pattern detection and stereotyping. Across 6 studies, we find that superior pattern detectors efficiently learn and use stereotypes about social groups. This pattern holds across explicit (Studies 1 and 2), implicit (Studies 2 and 4), and behavioral measures of stereotyping (Study 3). We also find that superior pattern detectors readily update their stereotypes when confronted with new information (Study 5), making them particularly susceptible to counterstereotype training (Study 6). Pattern detection skills therefore equip people to act as na├»ve empiricists who calibrate their stereotypes to match incoming information. These findings highlight novel effects of individual aptitudes on social–cognitive processes.

Group identity as a source of threat and means of compensation: Establishing personal control through group identification and ideology

Goode, C., Keefer, L. A., Branscombe, N. R., and Molina, L. E. (2017) Group identity as a source of threat and means of compensation: Establishing personal control through group identification and ideology. Eur. J. Soc. Psychol., 47: 259–272. doi: 10.1002/ejsp.2259.

Abstract: Compensatory control theory proposes that individuals can assuage threatened personal control by endorsing external systems or agents that provide a sense that the world is meaningfully ordered. Recent research drawing on this perspective finds that one means by which individuals can compensate for a loss of control is adherence to ideological beliefs about the social world. This prior work, however, has largely neglected the role of social groups in defining either the nature of control threat or the means by which individuals compensate for these threats. In four experiments (N = 466), we test the possibility that group-based threats to personal control can be effectively managed by defensively identifying with the threatened group and its values. We provide evidence for the specificity of these effects by demonstrating that defensive identification and ideology endorsement are specific to the content of the group-based threat.

Hispanics choose vehicles that are about 5-8% more expensive

Visible Consumption and Race: Evidence from Auto-Loans. Konstantinos Tzioumis. U.S. Department of the Treasury Working Paper, July 2017.

Abstract: This paper uses auto-loan applications to assess differences in consumption preferences across races. After controlling for income and age, Whites and Blacks are found to have similar choices in terms of vehicle value, while Hispanics choose vehicles that are about 5-8% more expensive. These results add to the literature by drawing on documented choices rather than realized purchases.

Similarities in smell and taste preferences in couples increase with relationship duration

Similarities in smell and taste preferences in couples increase with relationship duration. Agata Groyecka et al. Appetite, https://doi.org/10.1016/j.appet.2017.08.035

Abstract: Numerous studies point to partners’ congruence in various domains and note an increase in their compatibility over time. However, none have explored a shift in chemosensory perception related to relationship duration. Here, we examined the relationship between the time heterosexual couples have spent together and the degree to which they share their gustatory and olfactory preferences. Additionally, we investigated whether these preferences are associated with relationship satisfaction. One-hundred couples aged from 18 to 68 years being together for a period between 3 and 540 months rated the pleasantness of a wide variety of olfactory and gustatory stimuli. We showed that both taste and smell preferences are more similar the longer couples have been in a relationship. We also observed a very interesting trend in terms of smell preferences, with relationship satisfaction being negatively related to congruence in smell preferences between partners. We discuss these results from the perspective of evolutionary psychology.

Keywords: Smell preferences; Taste preferences; Olfaction; Gustation; Diet; Evolutionary psychology

Bias and ignorance in demographic perception -- part of a very general pattern of human psychology

Bias and ignorance in demographic perception. D. Landy, B. Guay and T. Marghetis. Psychonomic Bulletin & Review, https://link.springer.com/article/10.3758/s13423-017-1360-2

Abstract: When it comes to knowledge of demographic facts, misinformation appears to be the norm. Americans massively overestimate the proportions of their fellow citizens who are immigrants, Muslim, LGBTQ, and Latino, but underestimate those who are White or Christian. Previous explanations of these estimation errors have invoked topic-specific mechanisms such as xenophobia or media bias. We reconsidered this pattern of errors in the light of more than 30 years of research on the psychological processes involved in proportion estimation and decision-making under uncertainty. In two publicly available datasets featuring demographic estimates from 14 countries, we found that proportion estimates of national demographics correspond closely to what is found in laboratory studies of quantitative estimates more generally. Biases in demographic estimation, therefore, are part of a very general pattern of human psychology—independent of the particular topic or demographic under consideration—that explains most of the error in estimates of the size of politically salient populations. By situating demographic estimates within a broader understanding of general quantity estimation, these results demand reevaluation of both topic-specific misinformation about demographic facts and topic-specific explanations of demographic ignorance, such as media bias and xenophobia.