Variations in intra-oral stimulation and nutritive sucking

Sucking records were made from 24 infants, aged 3-4 days, fed small amounts of their usual formula from nipples of different sizes (5/16-, 8/16-, and 11/16-inch diam). Polygraphic and observer measures showed that the large nipple elicited fewer sucks and a slower sucking rate; 5 infants seen on 2 successive days showed a more marked nipple preference on the second day. The results show that intra-oral stimuli control sucking for a nutriment in much the same way as they have already been shown to control nonnutritive sucking.