Dr Moffitt's team (the actual work was led by her colleague, Avshalom Caspi) looked at the effect on intelligence of breastfeeding, but in a genetic context.
One pioneering study in 2002 by Avshalom Caspi and Terrie Moffitt of Duke University genotyped over 1, 000 individuals in a community in New Zealand and assessed their levels of antisocial behavior in adulthood.