Electronic Thesis and Dissertation Repository

Thesis Format

Monograph

Degree

Master of Science

Program

Psychology

Supervisor

Schermer, Julie A.

Abstract

Hope is an important character strength and contributor to well-being. Although theory and empirical work have focused on individual variation, few studies have contributed a behavioural genetics perspective. The current study used twin modelling to explore genetic, common, and unique environmental contributions to Snyder’s cognitive trait hope. Data from the TwinsUK registry included 917 same-sex twin pairs [637 monozygotic (76 men, 561 women) and 280 dizygotic (15 men, 265 women)]. Modelling results were presented for composite scores, pathway and agency subscales, age- and sex-adjusted composites, and a women-only sample. The best-fitting model estimated heritability at 41 - 43% (36 - 38% in the subscales) with the remaining variance attributed to the unique environment. The findings underscore the substantial role of genetics and individualized experiences in predicting trait variation and provide a foundation for research to build upon Hope Theory and better understand the development and maintenance of this important trait.

Summary for Lay Audience

Hope is an important concept in positive psychology for predicting health and well-being. As such, a large amount of work has gone into understanding the factors that predict differences in how hope is expressed. In this area, research has focused mostly on personal experiences (i.e., nurture) rather than biological influences (i.e., nature). To help bridge this gap, the current study used a classic twin (or ACE) design which compares similarity in hope levels between identical twins (who share all their genes) and fraternal twins (who share about half), to estimate how much of the variation in hope is attributable to genetics compared to twins common and unique environments. The sample included 917 same-sex twin pairs [637 monozygotic (76 men, 561 women) and 280 dizygotic (15 men, 265 women)] from the TwinsUK registry. ACE modelling was applied to overall hope scores in the complete sample and a women-only sample, to scores adjusted for demographic (age and sex) effects, and to hope’s pathway thinking and agency thinking subscales. Results showed that genetic differences explained about 41 - 43% of the variation in hope, while 57 - 59% was attributed to individuals’ unique or non-shared environments. Genetic effects were somewhat smaller for the subscales (36-38%), while the common or shared family environment did not contribute meaningfully across all the modelled scores. The findings demonstrate that trait hope has a substantial genetic basis, but is also highly influenced by unique experiences, reinforcing the idea that hope can develop over time.

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

Download

Included in

Psychology Commons

Share

COinS