Very young babies know when they are about to be picked up and alter the posture of their bodies in preparation, new research has found.

According to European scientists, this is the first study to investigate how babies change their posture in anticipation of being lifted.

They found that most babies between two and four months of age know when they are about to be picked up as soon as their mothers come towards them with their arms stretched out. When this happens, the babies go still and stiffen, making it easier to be lifted.

"We didn't expect such clear results. From these findings we predict this awareness is likely to be found even earlier, possibly not long after birth," explained Prof Vasu Reddy of the University of Portsmouth in the UK.

She suggested that the way in which infant development is studied may have to be reconsidered because ‘infants seem to be able to understand other people's actions towards them earlier than previously thought'.

The findings were based on two studies. The first focused on 18 babies aged three months, while the second looked at 10 babies aged between two and four months.

In both studies, the babies were put on pressure mats, which measured changes in their posture during three stages - while their mothers chatted to them, when the mothers opened their arms and when the babies were actually picked up.

The study showed that babies as young as two months made specific changes to their posture when their mothers stretched out their arms to pick them up. These changes included raising or widening their arms so that the mother had space to hold the baby's chest, and stretching and stiffening their legs to increase rigidity and therefore stability.

The scientists also noted that at two and three months of age, the infant's gaze often tended to move from the mother's face to her hands when she stretched out her arms.

They said that the findings revealed two important points. Firstly, very young babies make changes to their posture to make it easier for them to be picked up before they are even touched. Secondly, the babies seem to learn how to fine tune the coordination of these movements, rather than having to learn different changes to their posture.

"In other words, they rapidly become more adept at making it easier for parents to pick them up," Prof Reddy pointed out.

Details of these findings are published in the journal Plos One.