Psychology researcher Paul Rozin of the University of Pennsylvania was prompted to investigate the ways in which individuals and institutions communicate their group membership as a result of many years of observation, after «noticing the behavior of people just promoted to a better position, or just after receiving a degree, or being admitted to
a relatively exclusive group.»
The rates of any and
exclusive breastfeeding in our control population (
group 1) were
relatively low at only 34 % and 9 %, respectively, six months after delivery.