Of all the health benefits linked to breastfeeding, its presumed impact on a child's later intelligence is likely the most controversial. Though a 1929 study by Carolyn Hoefer and Mattie Crumpton Hardy first made the connection, numerous studies since then have challenged these findings. Since mothers who breastfeed tend to have higher intelligence than non-breastfeeding mothers, researchers have argued that maternal IQ is more important than breastfeeding in how their children develop intellectually. When maternal IQ is controlled for, the presumed relationship between breastfeeding and intelligence tends to disappear.
But is there really no intellectual difference between breastfed and non-breastfed children? There certainly seems little question breastfeeding helps ensure that infants are healthy and well-nourished. According to a policy statement by the American Academy of Pediatrics, Work Group on Breastfeeding, "“Epidemiologic research shows that human milk and breastfeeding of
infants provide advantages with regard to general health, growth, and development, while significantly decreasing risk for a large number of acute and chronic diseases”
Since good nutrition is essential in various indexes of brain development, including intelligence, more recent researchers have questioned a number of the studies seeking to disprove the breastfeeding-intelligence link. Since most of these studies were based on single IQ tests rather than more in-depth measures of cognitive functioning, more comprehensive research is needed.
To read more, check out my new Psychology Today blog post.