title: Bodily symmetry increases across human childhood.
abstract: BACKGROUND
  Although bodily symmetry is widely used in studies of fitness and individual differences, little is known about how symmetry changes across development, especially in childhood.
  
  
  OBJECTIVE
  To test how, if at all, bodily symmetry changes across childhood.
  
  
  METHODS
  We measured bodily symmetry via digital images of the hands. Participants provided information on their age. We ran polynomial regression models testing for associations between age and symmetry.
  
  
  METHODS
  887 children attending a public science event aged between 4 and 15 years old.
  
  
  METHODS
  Mean asymmetry for the eight traits (an average of the asymmetry scores for the lengths and widths of digits 2 to 5).
  
  
  RESULTS
  Symmetry increases in childhood and we found that this period of development is best described by a nonlinear function.
  
  
  CONCLUSIONS
  Symmetry may be under active control, increasing with time as the organism approaches an optimal state, prior to a subsequent decline in symmetry during senescence. The causes and consequences of this contrasting pattern of developmental improvement in symmetry and reversal in old age should be studied in more detail.
authors: Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, UK.
authors: David
authors: D
authors: Hope
authors: Timothy C
authors: TC
authors: Bates
authors: Dominika
authors: D
authors: Dykiert
authors: Geoff
authors: G
authors: Der
authors: Ian J
authors: IJ
authors: Deary
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006225:Hand / Q000033:anatomy & histology* / Q000254:growth & development; D006801:Humans; D008297:Male; D013997:Time Factors