BOTTLE-FED NEONATES PREFER AN ODOR EXPERIENCED IN-UTERO TO AN ODOR EXPERIENCED POSTNATALLY IN THE FEEDING CONTEXT

The head-orientation response of 2- and 4-day-old bottle-feeding neona tes was studied in paired-choice odor tests. Three tests were conducte d at Days 2 and 4 after birth to assess the development of the relativ e response between two salient odors from the prenatal and postnatal e nvironments: (a) amniotic fluid (AF) versus formula milk (FM), (b) FM versus control stimulus (distilled water), and (c) AF versus control s timulus. At both ages, AF and FM elicited positive orientation when pr esented simultaneously with the control stimulus, indicating that both odors were detectable and attractive to the infants. However; when AF and FM were presented concurrently, the infants expressed significant ly longer orientation response toward AF odor than toward FM odor at t he age of 2 and 4 days. Within the first 4 days of life, bottle-feeder s thus display olfactory preference for a prenatal substrate over a po stnatal substrate to which they were recurrently exposed in the feedin g situation. (C) 1998 John Wiley & Sons, Inc.