A mother's "holding" environment has been shown to be effective in reducing infant crying and irritability. When mothers hold or cuddle their infants they create a microenvironment with stimuli similar to those of the intrauterine environment. Several of these same stimuli were incorporated into a cradle designed to provide a similar "holding" environment for the infant when the mother was not there. Ninety healthy term newborn infants were randomized to an experimental (n = 45) or control group (n = 45). The experimental group used a cradle that produced motion, sound, tactile (containment), and reduced-light stimuli at stimulus levels that initially approximated intrauterine sensory stimulation levels and gradually decreased to the levels of the home environment over 16 weeks. The control group used an identical cradle with no stimulus modulation features. Infants were placed in their respective cradles from 2 hours after birth during the times they would normally be placed in an infant bed. The mother-infant interaction or parenting style was not changed or manipulated. Mothers' use of the cradles did not differ significantly. An electronic status monitor measured and recorded infant presence and crying in the cradles. The Brazelton Neonatal Behavioral Assessment Scale test was done at 1 to 2, 14, and 24 days of age by "blinded" examiners. Additionally, phone calls and home visits were conducted by a registered nurse.(ABSTRACT TRUNCATED AT 250 WORDS)