Self–transcendence as a measure of spirituality in a sample of older Australian twins

Abstract

Measures of self-transcendence, physical health and psychological well-being were included in a self-report Health and Lifestyle questionnaire administered to Australian twins aged over 50 between 1993 and 1995. Self-transcendence appears to be higher among older Australian women than men, and was significantly associated with religious affiliation, marital status (in women) and age (in men). No strong correlations were observed between self-transcendence and any measure of psychological or physical health. Additive genetic effects were found to be important in influencing self-transcendence, with heritability estimates of 0.37 and 0.41 for men and women respectively, whilst shared environment effects were not found to be significant. Multivariate modelling of self-transcendence scores and self-reported church attendance behavior indicated substantially different etiologies for these variables, with implications for methods of investigation of religiosity and spirituality.

Familial Resemblance in Religiousness in a Secular Society: A Twin Study

“…Conversely, in a solely Australian study, Kirk et al (1999a) show no effect of genetic factors and find that shared environmental factors have the largest effect in adulthood, accounting for about 60% of the variance in church attendance in twins over 50 years of age. Kirk et al (1999a) also study self-transcendence in this sample of older Australian twins and show that genetic factors contribute approximately 40%, while unique environmental factors contribute 50%, and shared environmental factors contribute 10% of the variance. Bouchard et al (1999) employ a construct of intrinsic and extrinsic religiousness in an American study and demonstrate significant heritability for both measures.…”

“…In other words, to some degree we are as we are in our behavior and personality because we have inherited genes that make us that way. Over the past decade, an increasing number of studies have explored the genetic and environmental influences on a rather new and perhaps provocative realm: religiousness, often using the twin study design to facilitate assessment of the impact of genetic, shared environmental and unique environmental factors (Kendler et al, 1997;Kendler & Myers, 2009;Kirk et al, 1999aKirk et al, , 1999bKoenig et al, 2005Koenig et al, , 2008Tsuang et al, 2002;Vance et al, 2010). The twin study design takes advantage of the fact that twins are reared in the same environment, but while monozygotic (MZ) twins share all of their genes, dizygotic (DZ) twins share on average half of their genes and hence differences in intrapair similarity between the two may indicate the presence of a positive heritability.…”

“…Familial Resemblance in Religiousness studies apply only one single item measure, often an affiliation to a religious denomination or church attendance (Kendler & Myers, 2009;Kirk et al, 1999aKirk et al, , 1999bKoenig et al, 2008), which may not be an adequate approach as religiousness is a multidimensional construct involving beliefs, practices, and perceptions of God (Hill & Pargament, 2003). Other studies compose different religious constructs categorized from factor analysis of several items relating to religious acts and beliefs or to spirituality, and often divided into intrinsic/personal and extrinsic/social religiousness (Kendler et al, 1997;Kirk et al, 1999a;Koenig et al, 2005Koenig et al, , 2008Tsuang et al, 2002;Vance et al, 2010) Most studies suggest that religiousness and religious behavior in childhood and adolescence are largely influenced by shared environmental factors -children are much influenced by the environment in which they grow up - (Winter et al, 1999), but as the twins age the picture changes and in adulthood genetic factors and unique environmental factors become increasingly influential (Kendler & Myers 2009;Koenig, 2011;Koenig et al, 2005Koenig et al, , 2008.…”

“…Other studies compose different religious constructs categorized from factor analysis of several items relating to religious acts and beliefs or to spirituality, and often divided into intrinsic/personal and extrinsic/social religiousness (Kendler et al, 1997;Kirk et al, 1999a;Koenig et al, 2005Koenig et al, , 2008Tsuang et al, 2002;Vance et al, 2010) Most studies suggest that religiousness and religious behavior in childhood and adolescence are largely influenced by shared environmental factors -children are much influenced by the environment in which they grow up - (Winter et al, 1999), but as the twins age the picture changes and in adulthood genetic factors and unique environmental factors become increasingly influential (Kendler & Myers 2009;Koenig, 2011;Koenig et al, 2005Koenig et al, , 2008. This shift is shown in American follow-up studies of religiousness and the importance of religion (Koenig et al, 2008) and frequency of church attendance (Kendler & Myers, 2009), and can possibly be explained by a decreasing social influence from the families as the twins age and an increasing influence from unique environmental factors such as individual experiences, for example, a personal crisis.…”

The genetic and environmental relationship between Cloninger's dimensions of temperament and character

“…This is in contrast to the heritable dimensions of temperament for which familial aggregation is best explained by additive genetic effects alone Stallings et al, 1996). Previously, Kirk et al found that additive genetic effects accounted for 48% of the variance in Self-transcendence scores for men and women alike (Kirk, Eaves, & Martin, 1999). In addition to demonstrating trait heritability, it is desirable to determine whether a trait provides additional information beyond that which can be already explained by existing personality taxonomies.…”