Psychosocial adversity and emotional instability: an application of gene–environment interaction models

Personality and personality disorders: introduction to the special issue

The study of extreme variants of phenomena has always been a challenge for science. While the science of personality has roots in several traditions, historically numerous personality theories and constructs for the assessment and explanation of individual differences have strongly been influenced by the progress made in conceptualizing extreme states of psychological functioning. Yet, division of labour resulted in psychiatry and clinical psychology focusing on deviant or maladaptive and personality psychology specializing on the normal range of individual differences. This special issue of the European Journal of Personality is driven by the idea that linking the study of personality and psychopathology offers insights that neither discipline can achieve on its own. Copyright © 2005 John Wiley & Sons, Ltd.

Consumer Behaviour of Seniors on the Cow’s Milk Market in Slovakia: Silver Persuading Techniques

Seniors are usually perceived as an unattractive segment, mostly due to their limited spending power. In Slovakia, the number of seniors has continuously been increasing. The population has been growing older. In Europe, more than a quarter of the population is expected to be aged 65 years or older by 2050. That is the main reason why we have to understand the consumer behaviour and decision-making processes of senior consumers. The presented paper deals with the consumer behaviour of seniors on the Slovak market of cow’s milk since it is the most commonly consumed type of milk in Slovakia. Opinions of nutrition specialists differ on whether it is beneficial or not for humans to consume milk. However, in general, milk is considered to be an essential component of the diet not only for children but also for adults and especially for seniors because of its high nutrition value. Milk and dairy products should be a daily part of the seniors’ diet. Since older people no longer have the necessary enzyme (lactase) to break down milk sugar (lactose), it is recommended to consume milk products that no longer contain milk sugar, but that lactic acid is produced by fermentation. Sour milk products such as curd, yoghurt or kefir have a beneficial effect on stomach, intestines and also the immune system. Long-term insufficiency of calcium intake causes osteoporosis – a disease that manifests itself in bone loss and structural disorders. It leads to increased fracturing of the bones and thus an increased risk of health complications resulting from there. This study explores senior consumers’ preferences for milk and their decision-making strategies on the market of cow’s milk. The study is oriented primarily on visual cues catching the attention of consumers. Anonymous survey was conducted on a sample of 470 senior respondents (210 males and 260 females) aged 61 – 84. Using selected psychological tools and a short questionnaire it was found out that Slovak seniors prefer traditional motives and bright colours on the milk packaging, they highly prioritise price over quality of milk products and in comparison with young adults, they are loyal to chosen products or brands. Seniors who score higher on the scale of neuroticism personality trait state that the packaging of milk products is significant for their decisions. Seniors with higher emotional stability tend to experiment more on the market of milk. Keywords cow’s milk, seniors, consumer behaviour, packaging, persuading techniques.

Emic vs etic frame of reference personality assessment in the prediction of work-related outcomes

Purpose

The purpose of this paper is to investigate the effect of both work-related and emic contextualization of personality measurement in the prediction of work-related outcomes.

Design/methodology/approach

In total, 224 employees completed work-contextualized and non-contextualized Big Five model measures, as well as contextualized emic personality measures, together with a number of measures for work-related outcomes.

Findings

Results showed that, after controlling for demographic variables and non-contextualized etic factors, etic contextualized factors predicted occupational stress, work engagement, job satisfaction, work frustration, turnover intention, career satisfaction and organizational citizenship behavior. After controlling for demographic variables, non-contextualized etic factors and contextualized etic factors, emic contextualized personality factors predicted work engagement, job satisfaction, absenteeism, counterproductive workplace behaviors and organizational citizenship behaviors.

Research limitations/implications

The study has a number of limitations. First, the sample contained participants recruited from a low number of professional areas. Second, the sample consisted mostly of women, and relying on unbalanced samples may lead to construct irrelevant variance.

Practical implications

By using a combination of etic personality measures and contextualized emic personality measures, organizations can better predict a number of organizational outcomes related to extra-role performance, such as those considered in the present study.

Originality/value

This research showed that, in the case of personality assessment, using a double form of contextualization – frame of reference and culture – an increment in the prediction of organizational behaviors can be obtained.

Romantic Relationship Satisfaction Moderates the Etiology of Adult Personality

The heritability of major normative domains of personality is well-established, with approximately half the proportion of variance attributed to genetic differences. In the current study, we examine the possibility of gene × environment interaction (G×E) for adult personality using the environmental context of intimate romantic relationship functioning. Personality and relationship satisfaction are significantly correlated phenotypically, but to date no research has examined how the genetic and environmental components of variance for personality differ as a function of romantic relationship satisfaction. Given the importance of personality for myriad outcomes from work productivity to psychopathology, it is vital to identify variables present in adulthood that may affect the etiology of personality. In the current study, quantitative models of G×E were used to determine whether the genetic and environmental influences on personality differ as a function of relationship satisfaction. We drew from a sample of now-adult twins followed longitudinally from adolescence through age 29. All participants completed the Multidimensional Personality Questionnaire (MPQ) and an abbreviated version of the Dyadic Adjustment Scale. Biometric moderation was found for eight of the eleven MPQ scales examined: well-being, social potency, negative emotionality, alienation, aggression, constraint, traditionalism, and absorption. The pattern of findings differed, suggesting that the ways in which relationship quality moderates the etiology of personality may depend on the personality trait.

Beliefs about unmet interpersonal needs mediate the relation between conflictual family relations and borderline personality features in young adult females

BACKGROUND

Central to most theories of borderline personality disorder (BPD) is the notion that the family environment interacts with genetically-based vulnerabilities to influence the development of BPD, with particular attention given to risk conferred by conflictual familial relations. However, the extent to which family conflict may relate to the development of BPD via related interpersonal beliefs is currently unknown. This study sought to test the hypothesis that the concurrent relation between conflictual family relations and borderline features in female college students is explained by beliefs associated with real or perceived unmet interpersonal needs (captured by Joiner's [2005] Interpersonal Psychological Theory, specifically thwarted belongingness and perceived burdensomeness).

METHOD

The sample included 267 female undergraduates ages 18-25 years (M = 20.86; SD = 1.80). Level of borderline personality features, unmet interpersonal needs, and family conflict were assessed.

RESULTS

Bivariate analyses revealed significant relations between both thwarted belongingness and perceived burdensomeness, conflictual family relations, and borderline features. Multivariate analyses revealed that thwarted belongingness and perceived burdensomeness both mediated the relation between family conflict and borderline personality features, thus supporting a multiple mediation model.

CONCLUSIONS

This cross-sectional study is a preliminary step towards confirming the broad theoretical hypothesis that conflictual family relations relate to beliefs about thwarted belongingness and perceived burdensomeness, which, in turn, relate to borderline personality pathology. Limitations and areas of future research are discussed.

Parenting as a reaction evoked by children's genotype: a meta-analysis of children-as-twins studies

Parenting has been extensively studied but mostly as a causal factor influencing child outcomes. The aim of the current article is to examine the child's side of the relationship by meta-analyzing studies which used quantitative genetic methods that provide leverage in understanding causality. A meta-analysis of 32 children-as-twins studies of parenting revealed a heritability estimate of 23%, thus indicating that genetically influenced behaviors of the child affect and shape parental behavior. The shared- and nonshared-environmental estimates, which amounted to 43% and 34%, respectively, indicate not only substantial consistency in parental behavior but also differential treatment within the family. Assessment method, age, and parenting dimension were found to be significant moderators of these influences. Our findings stress the importance of accounting for genotype-environment correlations in child-development studies and call into question previous research that interpreted correlational results in unidirectional terms with parenting as the sole causal factor.

Culture Moderates the Genetic and Environmental Etiologies of Parenting

A cultural behavior genetic approach was introduced as a prospective means to describe psychological differences between cultures. We compared genetic and environmental influences on remembered parenting for samples of twins from Japan and Sweden. Data were collected from 720 pairs of young adult Japanese twins and 824 pairs of adult Swedish twins using the Parental Bonding Instrument. In both samples, a very similar phenotypic factor structure was developed for maternal and paternal parenting. However, the genetic and environmental contributions were different. Parenting in Japan showed more genetic influences, whereas parenting in Sweden showed more shared environmental influences. Moreover, covariation among the six dimensions of parenting (i.e., maternal and paternal Warmth, Protectiveness, and Authoritarianism) was due to genetic correlations in Japan and to shared environmental correlations in Sweden. These results are consistent with the cultural psychology argument that parenting practices are child centered in Japan but parent centered in the West.

The University of British Columbia Twin Project: Personality is Something and Personality Does Something

The University of British Columbia (UBC) Twin Project is a registry of approximately 1500 pairs of reared-together twins recruited from Vancouver, British Columbia and surrounding municipalities. The focus of the project is to examine personality and its disorders from a behavioral genetic perspective. The primary measures include self-report measures of variables from the major models of personality and personality disorders. Subsamples of the study have also been surveyed on a wide range of psychiatric conditions and symptoms, including, for example, substance use, mood, anxiety, coping, posttraumatic stress disorder, schizotypy, and several measures of the environment and experience. Also surveyed are general health and basic psychological processes including cognitive ability. This broad assessment has enabled us to examine not only the structure of personality, but also its potential role in psychopathology and other psychological processes. A feature of the project is that the measures selected reflect current thinking in the field as opposed to traditional psychiatric diagnostic criteria. The UBC Twin Project has been used in a number of collaborative projects on personality and psychopathology with other worldwide twin registries. At the present time, no DNA has been collected; however the facility to collect these data is available. Collaborative projects on this and future questionnaire studies are welcome.

Socioeconomic background and the developmental course of schizotypal and borderline personality disorder symptoms

Low socioeconomic status (SES) background has been identified as a risk for several mental disorders. However evidence regarding SES and the developmental course of personality disorder (PD) has not been addressed. Nor is it clear whether an SES relationship to PD symptom course may be attributable to known associated risks. Further, specificity of such relationships to a particular PD diagnostic pattern independent of comorbidity with other PD or with depression has not been investigated. Data are from a general population studied longitudinally between ages 10 and 36 in four assessment waves. Effects of SES-associated risks on the level of symptoms of schizotypal and borderline disorders are estimated and compared to effects on depressive symptoms. Low family SES had robust modest independent effects on both PDs over the entire age span despite substantial cumulative effects of trauma history, stressful recent life events, IQ, poor parenting, and comorbid symptoms. SES effects on depressive symptoms were generally absent, but a small "protective" effect of low SES appeared when comorbidity with PD symptoms was taken into account. Cumulatively, these risks account for developmental failures of substantial magnitude and consequence, marking the importance of understanding the remaining mechanisms of SES effects and programmatic implications for minimizing associated risk.

Etiology of the dimensions of anxiety sensitivity: a behavioral-genetic analysis

Evidence suggests that anxiety sensitivity (AS) contributes to individual differences in fearfulness and to the risk of developing anxiety disorders. To investigate the origins of AS we administered the Anxiety Sensitivity Index to 245 monozygotic and 193 dizygotic twin pairs, comprising 658 women and 218 men. Scores were calculated for the most widely replicated AS dimensions; physical, cognitive, and social concerns. For women, each dimension was influenced by a combination of genetic and environmental factors. Heritability in women significantly increased with AS scores, indicating that severe forms of AS, compared to milder forms, are more strongly influenced by genetic factors. Correlations among AS dimensions for women could be explained by genetic and environmental factors influencing all three dimensions. For men, dimensions were influenced by environmental but not genetic factors. Correlations among dimensions for men could be explained by environmental factors influencing all dimensions. Overall, the findings reveal that AS has more complex etiology than previously recognized; its dimensions appear to arise from a mix of dimension-specific and non-specific etiologic factors, whose importance vary as a function of sex and severity.

The Behavioral Genetics of Personality Disorder

Behavioral genetics research has opened a new window on understanding personality disorder. The earliest studies were focused on establishing the relative contributions of genes and the environment in these disorders. Although these studies provided solid evidence of the importance of genetic and environmental influences on personality disorder and showed that all aspects of personality disorder are subject to genetic influence, heritability studies are limited because they are not helpful in explicating causal mechanisms. More recent research has focused on the relative contributions of the covariation of personality disorder diagnoses and traits, which allows one to examine etiological relationships. These developments are leading to major changes in ideas about what constitutes the environment and nature of the interplay between genes and environment. The present review examines major themes in this growing body of research in the context of current issues in the personality disorders.

Specification, testing, and interpretation of gene-by-measured-environment interaction models in the presence of gene-environment correlation

Purcell (Twin Res 5:554-571, 2002) proposed a bivariate biometric model for testing and quantifying the interaction between latent genetic influences and measured environments in the presence of gene-environment correlation. Purcell's model extends the Cholesky model to include gene-environment interaction. We examine a number of closely related alternative models that do not involve gene-environment interaction but which may fit the data as well as Purcell's model. Because failure to consider these alternatives could lead to spurious detection of gene-environment interaction, we propose alternative models for testing gene-environment interaction in the presence of gene-environment correlation, including one based on the correlated factors model. In addition, we note mathematical errors in the calculation of effect size via variance components in Purcell's model. We propose a statistical method for deriving and interpreting variance decompositions that are true to the fitted model.