The baby gurgles and giggles, pokes out its tongue and grasps a proffered finger. Then, inexplicably, it starts to cry.
Every new parent knows the distress caused by the inability to interpret a baby's body language. Now a new video produced by the NSPCC promises to unlock its secrets.
The video shows how parents can recognise early signs of displeasure or stress by learning to interpret the signals babies give from birth. Parents can then adjust their routines and behaviour to best match the individual needs and sensitivities of their child.
Called The Social Baby, the video is based on the book of the same name by Lynne Murray, professor of developmental psychology at Reading University. It includes tips on how to handle typical situations.
For example, when laying a child to sleep, look to see how they react. Some babies are very sensitive to light and noise and may direct their carer to where the distraction is.
From birth babies like to engage with people and are fascinated by the human face. But if you move your face too close or too quickly they may find this intrusive. For example, the video shows a baby who is only a few hours old poking its tongue out in response to a similar gesture from its father signalling it is ready to play.
Although babies are very sociable, sometimes they just want to be with their mother or father. In the NSPCC video, a five-week-old baby turns away from the unfamiliar health visitor, signalling she wants to be returned to her mother's lap.
Babies tire very quickly and although they may be happy to engage and play, it may only be for a few minutes. The video shows a 10-week-old baby rubbing her face with one hand, indicating she wants a break from playing with her father.
Professor Murray said: "The tips in the video are the result of many years of listening to parents, observing babies and finding out what works. It is not just for those who are having difficulties, but also those who want to deepen their relationship and bring up a more contented baby." Around 15 per cent of babies are born with an increased sensitivity which makes them prone to cry more easily and renders them unable to cope with a lot of stimulation. Professor Murray said: "Once they become upset they can be hard to soothe and calm down, and this can be very distressing for parents. It can be useful for them to learn the signs that the baby may be flagging a bit so that they can intervene before the situation escalates."
Few parents had experience of interacting with infants before they had children of their own and there was no training for parenthood.
"That is unusual in evolutionary terms. Most people in the past would have had a lot more experience of infant behaviour from living in extended families," Professor Murray said.
She added: "Even for those who are experienced, if there are other things preoccupying them they may have difficulty tuning in, so might benefit from some help."
The Social Baby video, £18.50 inc p&p, from NSPCC Publications, Weston House, 42 Curtain Road, London EC2A 3NH.