Biomaterial Database

Genetic and environmental mechanisms determining intelligence, neuroticism, extraversion and psychoticism: an analysis of Irish siblings. 1989

R Lynn, and S Hampson, and E Agahi

Department of Psychology, University of Ulster, Coleraine, Northern Ireland, UK.

The theory that shared family environment has an effect on intelligence but no effect on personality was examined by a study of correlations between young adolescent Irish siblings for intelligence, neuroticism, extraversion and psychoticism. The correlations obtained for 386 sibling pairs were 0.48 (intelligence), 0.06 (neuroticism), 0.31 (extraversion) and 0.14 (psychoticism). The correlation for IQ confirms the operation of both genetic and shared family effects on intelligence. The low correlations for neuroticism and psychoticism confirm the thesis that shared family effects have no influence on these traits. They are also inconsistent with an additive genetic model and suggest that non-additive genetic mechanisms are present to make siblings so dissimilar. The higher sibling correlation for extraversion suggests that shared family environment does have some effect on this trait among young adolescents and is also consistent with an additive genetic model.

UI	MeSH Term	Description	Entries
D007360	Intelligence	The ability to learn and to deal with new situations and to deal effectively with tasks involving abstractions.
D007494	Ireland	A country in western Europe, occupying five-sixths of the island of Ireland in the North Atlantic Ocean, west of Great Britain. The capital is Dublin.	Eire,Ireland, Republic of,Irish Free State
D008297	Male		Males
D009497	Neurotic Disorders	Disorders in which the symptoms are distressing to the individual and recognized by him or her as being unacceptable. Social relationships may be greatly affected but usually remain within acceptable limits. The disturbance is relatively enduring or recurrent without treatment.	Neuroses,Psychoneuroses,Disorder, Neurotic,Disorders, Neurotic,Neurotic Disorder
D010553	Personality Development	Growth of habitual patterns of behavior in childhood and adolescence.	Development, Personality
D010556	Personality Tests	Standardized objective tests designed to facilitate the evaluation of personality.	Personality Test,Test, Personality,Tests, Personality
D011618	Psychotic Disorders	Disorders in which there is a loss of ego boundaries or a gross impairment in reality testing with delusions or prominent hallucinations. (From DSM-IV, 1994)	Psychoses,Psychosis, Brief Reactive,Schizoaffective Disorder,Schizophreniform Disorders,Psychosis,Brief Reactive Psychoses,Brief Reactive Psychosis,Disorder, Psychotic,Disorder, Schizoaffective,Disorder, Schizophreniform,Disorders, Psychotic,Disorders, Schizoaffective,Disorders, Schizophreniform,Psychoses, Brief Reactive,Psychotic Disorder,Reactive Psychoses, Brief,Reactive Psychosis, Brief,Schizoaffective Disorders,Schizophreniform Disorder
D002648	Child	A person 6 to 12 years of age. An individual 2 to 5 years old is CHILD, PRESCHOOL.	Children
D005120	Extraversion, Psychological	A state in which attention is largely directed outward from the self.	Extraversion (Psychology),Extraversion, Psychology,Extroversion, Psychological,Extroversion, Psychology,Extraversion,Extroversion,Extroversion (Psychology),Psychological Extraversion,Psychological Extroversion,Psychology Extraversion,Psychology Extraversions,Psychology Extroversion
D005260	Female		Females