Dr. David M. Levy, a child psychiatrist of New York City, concluded, after a series of clinical studies of children1 and experiments with animals,2 that babies suck their thumbs primarily because they do not get enough sucking from breast or bottle.
As a nurse in a Child Health Station of the Department of Health of the City of New York, I had a ready opportunity to test this conclusion. Furthermore, I was sufficiently well acquainted with the mothers who attended the station to be able to select those whose information was reliable. Even so it was necessary, after a preliminary study, to dismiss a number of informants because they were vague about changes in feeding schedules.
Only infants 7 to 8 months of age were selected, and data were collected concerning the feeding schedules followed during the first seven months. Fifteen known thumb suckers and fifteen known non