States of Consciousness in Infants

Not so long ago, the newborn infant was thought of as neurologically insufficient, subcortical in behavior. Nothing in this description fits the kind of predictable, directed responses one sees in a newborn when in a social interaction with a nurturing adult. When positive rather than intrusive stimuli are utilized, the newborn has amazing capacities for alerting and attention, and for suppressing interfering reflex responses in order to attend. Newborns respond to and interact with their environment from birth. But in order for an adult to engage this response, a knowledge of the newborn's ongoing is necessary. These states are the necessary context for understanding a newborn's reactions. Depending upon the newborn's state, stimulation is either appropriate or inappropriate. When appropriate stimuli are offered in appropriate states, an intact and adaptable central nervous system can be observed even in the most premature infant. To say that newborn babies function by controlling their state of attention or consciousness may be going too far, but such control seems to be within the capacities of a healthy, normal newborn (Brazelton, 1984)¹.

Labels for refer to the level of availability of the newborn. States range from deep and light sleep states, to a semiconscious, then to an alert and very available state, on to fussy, and then to unreachable crying. In research at the Child Development Unit at Boston Children's Hospital, we [TBB] have found that state range and state control in the newborn are the best predictors of cognitive and social performance at eighteen months (Lester et al., 1985)². Not only does state determine the capacity of babies to take in information and to use it, but it will also affect the kind and degree of response they will make. A trained observer quickly becomes able to predict which response a baby will make to a negative and to a positive stimulus in each state of consciousness. Newborns will not be unpredictable if one accounts for the states within which they are reacting. State, then, appears to be a basic regulatory system. If new-borns can maintain control over their states, they can regulate when and whether they take in and respond to the world around them. For example, in a noisy, overstimulating environment, newborns will either go into a deep sleep state or cry in an unreachable way.

One of a parent's first jobs is to learn to recognize and predict their baby's in order to know whether he or she will be available-for feeding, sleeping, and for interaction. The six states, as we currently understand them, are as follows:

The Six States

Deep sleep. Eyes are firmly closed, breathing is deep and regular, and there is no motor activity. At regular intervals but many seconds apart, the baby may have brief startles, but will not rouse. In this state, the baby is relatively unreachable to outside stimuli. This state occurs in roughly four-hour cycles in full-term newborns. Premature infants have less well defined cycles of this kind of sleep, and its occurrence is a sign of maturity and of good nervous system function in a disordered or high-risk baby. Obviously, this state serves an important purpose, to rest and organize an immature and easily overwhelmed nervous system. Its recurrence in short cycles over the day serves babies well. As they mature, they can postpone the need for deep sleep longer and longer. (See Sleep cycles, below.)

Active sleep (REM, or rapid-eye-movement, sleep). In this light or active sleep, babies are more vulnerable to the outside world. Their eyes will be closed, but slow, rotating movements may be apparent. Body activity ranges from minor twitches to short bouts of writhing and stretching. Breathing is irregular, rather shallow at times, and faster than that seen in sleep. Facial movements will include frowns, grimaces, smiles, twitches, mouth movements, and sucking. The predominance of REM sleep in normal newborns has led to the hypothesis that in this state brain growth and differentiation occur.

Drowsy, in-between state. The infant's eyes may open and close, or they may be partially or fully open, but they will be dazed in appearance. At times, there may be rather smooth movements of the arms and legs. Breathing is regular, but faster and shallower than that observed in sleep. Stimulation in this state is likely to arouse a baby to a more alert, responsive state.

Awake, alert state. The infant's body and face are relatively quiet and inactive, with eyes that are "bright and shining" in appearance. Visual and auditory stimuli will bring predictable responses. In early infancy, this state is likely to be short-lived, but by 2-3 weeks, a baby may be able to maintain it for as much as 20-30 minutes at a time. For parents, the deepest rewards occur in these times.

Alert but fussy state. This is a transitional state to crying. Babies are available to external stimuli and may still be soothed or brought to an alert state by attractive stimuli. If the stimulation gets to be too much, they are likely to break down to fussing again. Movements are jerky, disorganized, and make infants fuss even more when they set off massive startles in themselves.

Crying. Crying serves many purposes for the baby. From the first, it is the most effective mode for attracting a caregiver. Not only are there at least four types of cries (pain, hunger, boredom, discomfort) which are distinguishable early in the baby's life, but it seems as if the baby were programmed to try to communicate by crying in these various ways. A crying baby sets off an automatic response of concern, responsibility, and guilt in parents. They feel compelled to respond, to settle the baby's reason for crying. When they are able to, they feel reinforced as parents.
A mother can recognize her baby's cry from that of other newborns by the third day (Boukydis, 1979)³. She can begin to distinguish between pain, hunger, and boredom cries by the end of the second week. A father recognizes them by three weeks. Crying is, obviously, an important communication system for all of them, a complex signaling system in which babies express themselves differentially from the first (Lester & Zeskind, 1982)². By the second or third week, a kind of fussy crying occurs periodically throughout the day-usually in a cyclic pattern-which seems to discharge and help to regulate the states that ensue. After a period of such crying, the newborn may be more organized for a while and may sleep more deeply.
Although parents learn early to distinguish the various kinds of crying, they may also attribute many inappropriate meanings to it. We will see the results of this misinterpretation in Part V.

Sleep Cycles
The length of sleep cycles (REM-active and deep sleep) changes normally with maturation of the nervous system. As we mentioned, in a full-term baby, sleep and waking occur in approximately 4-hour cycles. Within these cycles, a baby is in deep sleep for 45-50 minutes and will then rouse to become active but still in light sleep. After awhile, he or she will settle back down to deep sleep. These cycles go on all day and night whenever the baby is asleep. A lack of regularity in these cycles may indicate problems in the development of the nervous system (Thoman, 1975)⁴. Learning to sleep for a 4-hour period already involves some learning of handling REM and deep-sleep cycles.

Learning to sleep longer than three to four hours at night is a more complicated process. First of all, the nervous system must mature so that the baby can handle stimuli from the environment without waking up. In order to sleep beyond these 3-4-hour cycles, babies must develop reliable behavioral patterns which serve to comfort them when they are trying to get from light sleep into a deeper sleep. Sucking fingers and scrabbling about for a comfortable spot are among these self-comforting measures.

Immature or hypersensitive babies take longer to stretch out their sleep at night. Not only are the sleep cycles of these babies shorter, but their ability to shut out stimulation in order to return from light to deep sleep is impaired. They will need extra time and pressure from the environment before they become able to keep themselves from waking at short intervals every time they come up to REM sleep.

Learning to sleep at night is tied to daytime patterns. Regular naps and regular feedings help. Babies who start to manage for themselves when frustrated during the day are more likely to learn patterns necessary for nighttime. Once parents understand a baby's needs and responses, they feel more confident in holding off for feedings in the daytime and in gradually encouraging the infant toward a regular, predictable pattern. This will help the infant learn to stretch out at night. As we will see in Part V, if there is a mismatch, and parents do not understand the baby's patterns, the interaction can become more and more anxious and disordered.

Habitunation
Habituation is a protective response, a closing down of the nervous system against too much stimulation from the outside. It is essential to newborns' capacity for survival, helping them deal with potentially overwhelming demands on their immature nervous systems. When presented with a series of bright lights, babies first startle, then gradually respond less and less. Observable motor responses eventually cease. The heart rate and respiratory changes seen after the initial stimulus gradually diminish. The babies begin to breathe deeply and regularly until they appear to be in a deep sleep. An electroencephalogram will show changes similar to sleep in their brains.

This habituation response can be brought about by auditory, visual, or tactile stimuli. When these are repeated, the newborns will show gradually decreasing responses and appear to go to sleep. However, if the stimulus is varied slightly, they begin to become interested again, alert, and their heart rates increase. In fact, one can document a newborn's capacity to detect differences in duration and intensity of a stimulus by monitoring heart rate at such a time.

Although habituation produces a state similar to sleep, there are differences. These infants have tightened, flexed extremities, with little movement except jerky startles, and no eye blinks. The babies seem to be actively maintaining control over their environment, rather than relaxing into sleep.

In impaired or immature newborns, the capacity to habituate is not as effective, and these infants are more at the mercy of environmental stimuli of all kinds. This ability is also affected by medication, such as barbiturates given to mothers at the time of delivery. Not only is habituation an important means of self-protection but it suggests active regulation of state control in the newborn period. The infant shuts out intrusive stimuli and can attend more effectively to appropriate ones. Early interaction between parents and infants is greatly enhanced when a parent understands this important protective response.

¹Brazelton, T. B. Neonatal Behavioral Assessment Scale, 2nd edition. Philadelphia: Lippincott; London: Blackwell, 1984.

²Lester, B. M., J. Hoffman, and T. B. Brazelton. "The rhythmic structure of mother-infant interaction in term and preterm infants." Child Development 56(1984):15- 27

³Boukydis, C. F. Z. "Adult response to infant cries." Unpublished doctoral dissertation, Pennsylvania State University, University Park, 1979.

⁴Thoman, E. B. "Early development of sleeping behavior in infants." In N. R. Ellis (ed.). Aberrant Development in Infancy. New York: John Wiley, 1975.