Whether you bottle provender or nurse your baby could play a role in what script they favor to habituate later in life , according to a new field of study from the University of Washington . In a review of more than 60,000 mothers and their babies , the researchers square up that bottle feeding infant was associated with a high prevalence of them being left - handed even when account for known risk factor that may tempt which pass a tyke favor .
To shape how feeding an infant may determine their predominant hand , researchers gather data on the duration of breastfeeding as reported by the female parent through seven national surveys in five countries . They feel that breastfeeding for more than six months was tie in with 3 percent less odd - handed babies than those that were feeding bottle - fed , with about one in five left - handed bottle - give babies possibly being attributable to a lack of breastfeeding for more than six month .
" We think breastfeeding optimize the process the head undergoes when solidify laterality , " said written report author Philippe Hujoel in astatement . " That ’s significant because it allow for an independent line of grounds that breastfeeding may need to last six to nine months . "
Writing in the journalLaterality : Asymmetries of Body , Brain and Cognition , the scientists say their study shake off light source on when areas of the brain , such as those that control laterality , localize to one side in a process known as brain lateralisation . Breastfeeding , they write , may optimize this lateralization toward becoming right- or left - handed during a critical windowpane of clock time during the first nine month of early childhood .
“ [ Our ] current finding thus evoke that the critical period of intellectual lateralization , the time windowpane wherein brain lateralization is susceptible to bring up , starts sometime before the 3rd month in utero . The developmental origins of laterality and ends in infancy before the age of 9 calendar month , ” say Hujoel .
agree to the theme , former studies have found that “ breastfed infants have been reported to have increase righthandedness , increase intelligence agency , increase head circumference , decreased speech problems , and decreased multiple sclerosis , ” while other subject field have rede these affiliation as causal based on evidence that breastfeeding lead to more grey matter volume in the brain . However , these study do n’t always accurately account for socio - economic ingredient and health awareness ( among other divisor ) due to the difficulty in parse out discombobulate agent .
The survey does not imply that breastfeeding alone dictates what hand a nestling will favor later in spirit , as this is decide during foetal life and at least partially by genetics . Further , it ’s authoritative to note that although they used a random sample to boil down selection bias , used train examiners to cut down information prejudice , and that public availability of the data countenance for autonomous check of report preconception , the researchers note that further , broader enquiry is needed .
