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Genetic and environmental causes of the interrelationships between self‐reported fears. A study of a non‐clinical sample of Norwegian identical twins and their families
Author(s) -
Sundet Jon Martin,
Skre Ingunn,
Okkenhaug Jan J.,
Tambs Kristian
Publication year - 2003
Publication title -
scandinavian journal of psychology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.743
H-Index - 72
eISSN - 1467-9450
pISSN - 0036-5564
DOI - 10.1111/1467-9450.00326
Subject(s) - psychology , norwegian , situational ethics , expectancy theory , social psychology , developmental psychology , twin study , spurious relationship , sample (material) , behavioural genetics , heritability , statistics , evolutionary biology , philosophy , linguistics , mathematics , biology , chemistry , chromatography
The present study reports results from a study of the self‐reported fears of identical twins and their spouses and offspring. Factor analysis with oblique rotation of questionnaire responses yielded four correlated fear dimensions: situational fears, illness–injury fears, social fears, and fear of small animals. Models allowing for genetic and cultural transmission, together with specially correlated environments for twins, were fitted, both for separate fears and across fears. Simple models with only genetic and uncorrelated environments were sufficient to account for each the fear dimensions considered separately. The cross‐dimensional analyses revealed a genetic and an environmental factor common to the four fear dimensions, together with fear‐specific genetic and environmental factors. The impact of the common genetic and common environmental factor varied across dimensions. No evidence of cultural transmission or specially correlated twin environments of the cross‐dimensional environments was detected. It is concluded that both common and fear‐specific genes and (individual‐specific) common and fear‐specific environments are necessary to account for the data. The results are discussed in terms of the prepared learning hypothesis and the expectancy bias hypothesis.