This was a clinical trials study of self-regulation of rhythmic stimulation in preterm infants. Infants were enrolled in three regional hospitals and followed in four outlying hospitals. Forty-five premature infants, 22 males and 23 females, enrolled at 29-33 weeks conceptional age (CA) received in the isolette either a "breathing" teddy bear (set to breathe at one-half the infant's quiet sleep respiration rate) or a nonbreathing bear. Using time-lapse videorecording at a 60:1 ratio, subjects were recorded for 3 days at the beginning of the Intervention period and again for 3 days, 2 weeks later. After discharge from the hospital, the sleep of the subjects was monitored in the home for a 24-hour period on weeks 1, 2, 3, 4, and 5 after expected date of birth (postterm). Infants with a breathing bear spent more time in contact with the bear, and increased their contact over the two weeks. Postterm, the "breathing bear babies" showed more quiet sleep and a greater increase in quiet sleep over weeks. The results indicate that premature infants ("prematures") are capable of organizing their motility to express a preference for rhythmic stimulation, and that the experience facilitates neurobehavioral development.