Basic concepts


A baby’s behaviour is a cue that tells you how he feels and what he needs. Sometimes the message is clear, sometimes not.

A first step in understanding your baby’s behaviour is recognizing the various stages of wakefulness and sleep.

Stages of wakefulness and sleep

There are 3 stages of sleep – drowsiness, light sleep, and deep sleep – each with corresponding degrees of consciousness.

Similarly, there are 3 waking phases – quiet alert, active alert, and crying.

Deep sleep 

The baby’s eyes are closed. There is no movement beneath the lids. The face is relaxed and the baby is not moving. Breathing is regular. The baby seems comfortable and at ease. Sometimes she jumps or startles if disturbed by a sudden noise or change in the environment.

Light sleep  

The baby’s eyes are closed or partly open for a few moments. You can see the eyes move beneath closed eyelids. The baby might make small fleeting movements like smiling, chewing, or groaning, or that may even resemble sucking. Breathing can be uneven. Without moving much, the baby may occasionally startle, but the movements are slower and more controlled than in deep sleep. The baby can slip from light sleep to another sleep or waking state, depending on changes in the surroundings, such as noise level and so on.


 The baby’s eyes may open and close. The eyelids are droopy and the gaze seems to float up. The baby doesn’t seem ready for interaction. Movements are smooth and fluid. Though sensitive to surrounding activity, it may take a moment for the baby to react. The baby’s consciousness levels change frequently, depending on the surroundings.

Quiet alert  

The baby’s eyes are wide open, clear and bright. Attention may be focused on a person or an object. The baby listens to surrounding sounds. He is alert and responds quietly to stimuli, with gentle movements. This state is short and fleeting in newborns, especially if they are born preterm. This is the moment where interaction is most welcome and beneficial.

Active alert  

The baby’s eyes are open. He makes noises and moves around a lot. His arms and legs are active. Sometimes, he startles. It is hard to say whether or not he responds to stimulation, as he moves around so much.


The baby is crying loudly and it is hard to stop her. She moves around a lot. You will find suggestions later on in this website on how to quieten her.

Babies transition easily from deep to light sleep and then to drowsiness before quiet awakening. At that point, they are attentive to their surroundings and ready to interact. When tired, they simply go back to sleep. The transition from one cycle to another is generally gradual and smooth.

Babies born preterm or with health issues may have difficulty getting from one state of sleep or wakefulness to another. Transitions may be sudden and abrupt. Stages may be difficult to identify because they are not necessarily typical. Remember that the baby tires easily and needs lots of sleep. To facilitate transitions, you may want to tailor your activities and interactions to the baby’s state of wakefulness or sleep.

Good to know…

It is very important to allow your baby to sleep uninterrupted. One hour of continuous sleep is ideal to achieve deep sleep and fully recover. Proper sleep allows the brain to mature and the body to grow.

The effect of environment on behaviour

In an effort to explain newborn behaviour, an American psychologist by the name of Heidelise Als proposed that the baby constantly interacts with the environment.

When something in the surroundings changes, it poses a threat to the stability of 5 distinct subsystems in the body. These 5 subsystems act on each other to keep the infant functioning at his best at all times:

  1. Autonomic – vital life functions (breathing, heart beat, blood pressure, temperature, digestion, hormones)
  2. Motor – posture and movement
  3. State – sleep and wakefulness
  4. Attention/interaction
  5. Self-regulation – ability to manage the other four subsystems in tight balance

How well the baby reacts to maintain stability in a changing environment depends on the maturity of each of the subsystems. In preemies, development was interrupted before its time. Adapted to life in the womb, the subsystems are prematurely called upon to react to the outside world. Stability is the notion of “just enough but not too much”. According to Als and other researchers, a baby should be stimulated just enough to capture, deal with and organize the information (self-regulation) but not so much as to overload the system (leading to stress and decompensation). Als’ theory is called the Synactive Theory of Infant Development.

Here are two examples.

A mature newborn, born full-term and without complications, shows stability in the way she processes information from her surroundings. When overstimulated, she finds a way of self-regulating, of returning to calm, peace and quiet; for instance, by bringing her fist to her mouth, sucking on it, and falling asleep.

If the infant’s capacity to adapt to her surroundings and activities is overloaded, she may react by decompensating with disorganized behaviour; that is, she can’t find a way of protecting herself and returning to a calm status. For instance, a monitor alarm goes off in the NICU. 

The baby is jolted awake (disrupted sleep-wakefulness subsystem). The alarm keeps going; the arms and legs start moving erratically (disrupted motor subsystem), and then her breathing becomes irregular with gasps (disrupted autonomic subsystem). This type of situation is unfortunately quite common in the NICU.

To help you decode your baby’s behaviour, here are some signs of stability and signs of stress you might observe.

Signs of stability or stress in infants

Signs of stability Signs of stress
Autonomic subsystem
  • Regular heart beat
  • Regular breathing
  • Pink skin
  • Stable digestion
  • Irregular heart beat
  • Irregular or fast breathing
  • Gasping
Motor subsystem
  • Body in a rounded, flexed position
  • Arms and legs relaxed near body; hands near the face
  • Movements smooth, soft, symmetrical and synchronous
  • No stretched out position
  • Rigid and extended positions
  • Arms stretched out and stiff
  • Knees and legs stretched above the bed as if the baby was sitting mid-air
  • Fingers and toes stiff and splayed
  • Back arched
  • Baby curled tightly into a ball (arms, legs and trunk flexed and stiff)
  • Fisting – hands curled into tight fists
  • Hypotonia – arms, legs, and trunk limp or floppy
  • Movements flailing, frantic, twisting, shaking, or jerky
State subsystem (Sleep/wakefulness)
  • Clearly defined states of sleep and wakefulness
  • Smooth and gradual transitions from one state to another
  • Ambiguous states of sleep and wakefulness – unclear, difficult to identify
  • Sudden and abrupt transitions
  • Waking states are not conducive to interaction
    • Not alert enough – eyes seem to drift off or are glassy or dull; little movement
    • Too alert – calm and awake with eyes staring – fearful or panicked look, or hard to detach gaze from stimulus
  • Signs of discomfort
    • Groaning or other noises while asleep
    • Flailing movements
    • Facial expressions of discomfort
    • Creased eyebrows
    • Inconsolable crying and agitation
Attention/interaction subsystem
  • Active search to locate sound stimuli
  • Eyes bright
  • Face relaxed
  • Keen interest in surroundings – easy to spot source of baby’s interest
  • Clear and prolonged response to light, sounds, voices
  • Ability to transfer attention from one stimulus to another
  • Ability to maintain interaction
  • Indifferent to surrounding stimuli
  • Gaze floating, fleeting, or panicked
  • Tendency to avoid stimuli (turning the head away, avoidance movements, arms over the face)
  • Eyes squinting
Self-regulatory behaviours
  • Thumb-sucking
  • Grasping of someone’s finger, a piece of cloth, etc.
  • Interlacing of hands or feet
  • Bringing hands to mouth and face
  • Looking and focussing intently
  • Curling up (flexed position)

Good to know…

A preterm baby will be less prone to stress if presented with only one stimulus at a time; for example, his mother’s voice without other people around. Then, as the baby grows, he will learn to manage several stimuli together. It is important to always stay alert to your baby’s signals and behavioural cues.

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