Now you see them, and now you don’t: An evolutionarily informed model of environmental influences on human sex differences

Sex differences in mental rotation ability have been observed in many countries. A previous study of Finnish participants reported that genetic and environmental influences on mental rotation ability differ between sexes. In this study, we assessed genetic and environmental influences on variance in mental rotation ability in 649 Japanese twins using a mental rotation test. To explain the influence of sex on variance in mental rotation ability, we applied genetic analysis using the sex limitation model. The following two factors explained variance in mental rotation ability: (1) the additive genetic factor, which reflects the accumulated small influence of many genes, and (2) the unique environmental factor, which is a type of environmental factor that differs between co-twins. The shared environmental factor, a type of environmental factor common for co-twins, could not explain the variance in mental rotation ability. Furthermore, the additive genetic factor was the same between sexes (i.e., not qualitative sex differences for the additive genetic factor), indicating that the same genes affect mental rotation ability in both sexes. Despite this observation, the additive genetic influence was greater in males than in females. In contrast, the unique environmental influence was not different between sexes. Considering the current results and those of a previous study, the quantitative sex difference for the additive genetic influences in mental rotation ability may be universal, while the unique environmental differences may depend on the characteristics of specific populations.

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Developmental changes in genetic and environmental influences on Chinese child and adolescent anxiety and depression

Psychological Medicine ◽

10.1017/s0033291716000313 ◽

2016 ◽

Vol 46 (9) ◽

pp. 1829-1838 ◽

Cited By ~ 13

Author(s):

Y. Zheng ◽

F. Rijsdijk ◽

J.-B. Pingault ◽

R. J. McMahon ◽

J. B. Unger

Keyword(s):

Sex Differences ◽

Environmental Factors ◽

Transition Period ◽

Environmental Influences ◽

Child And Adolescent ◽

Developmental Changes ◽

Anxiety And Depression ◽

Future Research ◽

Late Childhood ◽

Adolescent Anxiety

BackgroundTwin and family studies using Western samples have established that child and adolescent anxiety and depression are under substantial genetic, modest shared environmental, and substantial non-shared environmental influences. Generalizability of these findings to non-Western societies remains largely unknown, particularly regarding the changes of genetic and environmental influences with age. The current study examined changes in genetic and environmental influences on self-reported anxiety and depression from late childhood to mid-adolescence among a Chinese twin sample. Sex differences were also examined.MethodSelf-reported anxiety and depression were collected from 712 10- to 12-year-old Chinese twins (mean = 10.88 years, 49% males) and again 3 years later. Quantitative genetic modeling was used to examine developmental changes in genetic and environmental influences on anxiety and depression, and sex differences.ResultsHeritability of anxiety and depression in late childhood (23 and 20%) decreased to negligible in mid-adolescence, while shared environmental influences increased (20 and 27% to 57 and 60%). Shared environmental factors explained most of the continuity of anxiety and depression (75 and 77%). Non-shared environmental factors were largely time-specific. No sex differences were observed.ConclusionsShared environmental influences might be more pronounced during the transition period of adolescence in non-Western societies such as China. Future research should examine similarities and differences in the genetic and environmental etiologies of child and adolescent internalizing and other psychopathology in development between Western and non-Western societies.

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An I3 Theory analysis of human sex differences in aggression

Behavioral and Brain Sciences ◽

10.1017/s0140525x09990410 ◽

2009 ◽

Vol 32 (3-4) ◽

pp. 279-279 ◽

Cited By ~ 7

Author(s):

Eli J. Finkel ◽

Erica B. Slotter

Keyword(s):

Sex Differences ◽

Careful Analysis ◽

Human Sex Differences ◽

Aggressive Behaviors ◽

Theory Analysis ◽

I3 Theory

AbstractAccording to I3 Theory, individuals enact aggressive behaviors when (a) instigating triggers are severe, (b) impelling forces are strong, and/or (c) inhibiting forces are weak. Archer's analysis of human sex differences in aggression could be bolstered by a careful analysis of male-female discrepancies in reactivity (or exposure) to instigating triggers, proneness toward impelling forces, and/or proneness toward inhibiting forces.

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