title: The development of prosocial behaviour in children and adolescents: a twin study.
abstract: BACKGROUND
  Childhood psychopathology is associated with both high and low levels of prosocial behaviour. It has been proposed that the development of prosocial behaviour shows emerging and consolidating individual differences as children grow older. The influences on these individual differences have not previously been examined in children and adolescents using multiple raters in a genetically informative design.
  
  
  METHODS
  Twin data from 682 families based on parent and teacher reports were used to examine the genetic and environmental influences on prosocial behaviour in 5-16-year-olds. Effects of sex, age and rater were examined.
  
  
  RESULTS
  There were no significant differences in the magnitude of genetic and environmental influence on male and female prosocial behaviour. Declining common environment and increasing genetic influences were seen with age. This emerged as a trend in parent data and reached statistical significance in teacher data. When parent and teacher data were examined together in a rater bias model significant bias acting on the parent ratings emerged, in keeping with previous discrepancies between parental and observational measures. There was overlap in the phenotype rated by parents and teachers, with a highly heritable common underlying phenotype.
  
  
  CONCLUSIONS
  The influences on the distribution of prosocial behaviour in children and adolescents show declining shared environmental and increasing genetic influences with age. Parental assessments of prosocial behaviour show significantly higher scores than teacher reports and whilst there is overlap in the phenotype rated by parents and teachers, parents show significant bias in their ratings.
authors.affiliation: Department of Psychological Medicine, University of Wales College of Medicine, London, UK. scourfieldj@cardiff.ac.uk
authors.forename: Jane
authors.initials: J
authors.lastname: Scourfield
authors.forename: Bethan
authors.initials: B
authors.lastname: John
authors.forename: Neilson
authors.initials: N
authors.lastname: Martin
authors.forename: Peter
authors.initials: P
authors.lastname: McGuffin
mesh_terms: D000293:Adolescent; D041923:Adolescent Development; D000367:Age Factors; D002648:Child; D002657:Child Development; D002675:Child, Preschool; D004739:England; D005260:Female; D006801:Humans; D008297:Male; D010290:Parents; D010555:Personality Inventory / Q000706:statistics & numerical data; D012737:Sex Factors; D012919:Social Behavior; D012931:Social Environment; D011795:Surveys and Questionnaires; D014429:Twins, Dizygotic / Q000235:genetics / Q000523:psychology*; D014430:Twins, Monozygotic / Q000235:genetics / Q000523:psychology*; D014852:Wales / Q000453:epidemiology