A nomal infants behaviour is usually classified into six discrete behavioural states. These are quite sleep, active sleep, drowsy, alert, fussy and crying. In the alert state infants visually fixate on objects or faces and follow them horizontally and vertically [within one month); they also start them reliably towards a sound as if searching for it source.
After birth newborns are primarily nocturnal (keep awake mostly in the night). Gradually starting from around 15 days to one month of age the pattern becomes more settled with equal distribution of wakefulness in day and night. However typically at this age the nighttime sleep continues forewarn disturbed with frequent awakenings for feeding and otherwise.
Their sleeping pattern evolves with age and with neurological maturation most infants start sleeping for 5-6 hours at a stretch at night by 3-4 months of age. Also the day time sleep decreases progressively so that by 3-4 year. of age most infants sleep only occasionally during the day.