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We propose an alternative to the conventional view that limitations on infant functioning are handicaps to be overcome. According to our view, limitations, particularly of the sensory systems, produce adaptive advantages for infants by facilitating perceptual organization. During embryogenesis, developmental rates of sensory systems are unequal so that onset of functioning is sequential. We argue that such differential onset results in relative independence among emerging systems, thereby reducing competition which helps regulate subsequent neurogenesis and functioning. In addition to prenatal effects, neonatal sensory limitations are discussed as a major source of perceptual organization. Limitations reduce the amount of information with which the infant must contend and promote temporal contiguity between multimodal attributes of a stimulus. Although we focus on human perceptual development, our view is a broadly based comparative one. Thus, other organisms have evolved means of restricting sensory input, and evidence is cited suggesting the importance of this reduced input in regulating normal perceptual development.

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Two studies examined the theory that early limitations on sensory functioning contribute to the organization of a structure for perceptual development and intersensory functioning. Rat pups' eyelids were surgically opened on Day 7, following which the development of homing to their nest site was investigated, with each animal alone in its living cage. Control pups increased homing until Day 14, and then decreased. Experimental pups showed no such decline, with the highest rate of homing evident on the last day of testing. The importance of visual cues for this altered development of homing was examined. Visual cues for the home were reduced by removing all shavings during testing, while leaving an odorous substrate in place. Under these conditions, both groups showed the characteristic increase and decline in homing, suggesting that premature eyelid opening results in a modification of the distribution of attention to visual and olfactory characteristics of the nest.

The present study investigated intersensory interaction between auditory and visual stimulation in newborn infants. Stimulation in 1 modality may influence the response to stimulation in a second modality by changing the infant's state of arousal. To test this possibility, newborns' visual preferences for light patches of different intensity were examined following auditory stimulation. Visual preferences in infants not previously exposed to sound described an inverted U, indicating a preference for the light of intermediate intensity. In contrast, infants who were first exposed to sound preferred the light or lowest intensity. The results indicate that newborns attend to quantitative variations in stimulation and that these variations reflect both the objective stimulus intensity and organismic factors.

Newborns (N = 83) were presented with 3 conditions, each for 160 sec: tongue protrusion (TP), mouth opening (MO), and control (CO). In TP and MO, a female model alternated between demonstrating the gesture for 20 sec and presenting a passive, motionless face for 20 sec. In CO, she presented a passive face in both the “demonstration” and “passive” intervals. The participants' eyes were more widely open in the demonstration intervals of TP and MO than in the passive intervals, indicating that they were attending to the gestures. In TP, the participants produced more TP responses than MO responses, but in MO there was no effect, undermining the neonatal imitation hypothesis.

Among kittens the first 3 weeks of life are spent within the limited confines of the home. The mother establishes a delivery site during parturition; soon after the birth of the kittens, this site becomes the home region where all of the interactions between the mother and young, and among the young, occur. The kittens remain in the home until the beginning of the fourth week, which is long after their eyes have opened (i.e., seventh to ninth day), and they can crawl o r walk the distance required t o leave the home and wander around the cage. Undoubtedly, huddling of the litter and maternal nursing in the home contribute to the kitten's attachment t o this region. There is an additional reason for the kitten's remaining in the home: We have found that the home becomes an orientation center f o r the kittens of the litter. The following is a study of the development of the home as an orientation center for kittens during the first 3 weeks of life.When an animal adopts a posture o r maintains locomotion which is related to the amount o r source of stimulation in the environment, this is referred to as orientation (i.e., kinesis o r taxis). Among lower invertebrates and vertebrates, orientation is based largely upon innate responses t o stimulation of sensory receptors by directionalized stimuli (i.e., beam of light, chemical gradient, thermal gradient) under the appropriate organic conditions. Among newly born mammals, orientation responses a r e also based upon innate (i.e., present at birth) approach and withdrawal processes which enable the newborn to approach sources of weak stimulation and withdraw from sources of strong stimulation.2, 3

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