Babies still too small to speak know how to make jokes and form friendships, say researchers at an Australian university who have spent two years filming the behaviour of young children. Academics at Charles Sturt University are studying how children interact with other infants while in childcare using footage obtained from tiny cameras strapped to their heads. The study affords a \"baby\'s eye view\" of the world in which even simple objects such as spoons appear oversized, said Jennifer Sumsion, foundation professor of early childhood at the university. But it also shows that children aged from six months to 18 months use sophisticated but subtle non-verbal means to make friends and make each other laugh. \"We were very, very surprised to see just how sophisticated they were in terms of their social skills, their helping skills, in making sure they were inviting other children to be part of their group,\" Sumsion told AFP. Sumsion said babies interacted with each other by making eye contact and with hand gestures and humour. They used \"little social games that you wouldn\'t necessarily see unless you were looking very closely\", she said. Examples of this included children pretending to hand another child a toy, only to snatch it away at the last minute, or babies sitting close to each other in highchairs playfully switching their drink bottles around. In another instance caught on camera, a one-year-old girl tried to comfort a baby when she was frightened by gently placing a piece of see-through fabric over her so she could see out but feel protected. The researchers, who analysed the baby-cam footage alongside other video shot of the children at the same time, did not force the babies to wear the cameras and they were only attached for 10 to 15 minutes at a time. They hope the research will shed light on the secret world of babies and their experience in childcare. \"What surprised us though was the games that they were playing with each other, even at that age. It\'s really very positive to see,\" Sumsion said.