We all like to have gifts but quite often young children are more attracted to the boxes that the gifts come in. What can't you do with a cardboard box? If it's big enough it becomes a boat, a castle, a magic cave, the finest raw material of imaginative play.
Increasingly such play is seen as an essential step in the social and academic development of young children. Through it they gain in social understanding, they hone their communication skills in a way that a more formal academic curriculum cannot replace.
The inability to engage in pretend play, to use symbolic language and behaviour, to imagine, for example, that dolly is drinking a hot cup of tea from an empty yogurt pot, has long been regarded as one of three chief indicators of autism.
In many respects autistic children are all "one-offs", and tend to be highly idiosyncratic, but diagnosticians have highlighted these core areas of impairment: difficulties in social interaction and understanding; pretend play and communication; creativity and imagination.
However, a teacher of autistic children in North Yorkshire has undertaken ground-breaking research to prove that given the right kind of teaching - structured and highly theatrical - autistic children can learn to play imaginatively with other children.
Dave Sherratt teaches primary-age autistic children at Mowbray School for children with moderate to severe learning difficulties in Bedale. He is also a visiting tutor in autism at Birmingham University's school of education and is undertaking a PhD on pretend play and autism.
The first tranche of this research, "An investigation into pretend play with children who have autism and additional learning difficulties" is to be published by the Teacher Training Agency within the next two months.
Mr Sherratt had been struck by research indicating that it was possible to engage children in pretend play. These papers, however, were based on small clinical trials of children with a verbal and mental age of over four. Nobody had tested the hypothesis over a sustained period in a normal classroom setting, with children of a verbal and mental age below four and with additional learning difficulties. As both teacher and researcher he believed he was uniquely placed to further this research with his own pupils.
Mr Sherratt teaches seven autistic children with severe communications difficulties. Mowbray is a cheery, colourful school overlooking the Yorkshire countryside and the staff and children seem relaxed and friendly. But the children in Mr Sherratt's class live in a more isolated world.
David, aged five, is constantly distracted, noisily non-verbal, but he can recite whole passages from Tom and Jerry and Thunderbirds videos. One wall is covered with drawings of trucks by Timothy. He lives in a world of trucks; getting him to focus on any other subject is difficult. Timothy struggles with language, though he can write "Volvo" without problems. Pens, paper and normal classroom resources are out of reach as children like Kerry can become obsessed with eating them.
It's a tough job and establishing a group identity and communication between the children might seem an impossibility to onlookers. But through an intervention programme sustained over months and recorded on video, Mr Sherratt proved that the children could be taught to use and recognise pretend play in a social setting. During the programme they began to engage their peers in pretend play rather than playing alone or using repetitive and confrontational behaviour.
He said: "This is one small study, but we have gone so much further than in any previous research. What does it tell us about our perceptions of autism when one concrete impairment is so easily broken down?" One clip from the videos shows children acting out The Three Little Pigs story as Mr Sherratt reads it out. We see a child with a fox glove-puppet huffing and puffing and blowing down houses of straw and wood (an empty Persil box), though he is unable to blow the same box down when it is made of brick. His watching peers are unusually captivated, eager to join in.
A mother wrote that during a school holiday in the middle of the programme, her son Giles had played "dinosaurs" with other children, made guns out of sticks to shoot raptors, and used Lego to put his dinosaur to bed and take it to the pub.
Mr Sherratt said children were still playing "let's pretend" together after the summer holidays. The work seemed to have a lasting effect.
Developing social understanding in autistic children has always been a priority for Dave Sherratt. Through pretend play they can develop more flexible thinking and an understanding of the complexities of the social world. They can also start to realise that people have feelings and thoughts different from their own and the ability to "read between the lines" in given situations.
His success, he is convinced, is because he makes the process fun through the use of drama and pantomime, playfully exaggerating facial expressions, involving the children emotionally.
Dr Rita Jordan, senior lecturer in autistic spectrum disorders at Birmingham University's school of education, said: "This is very exciting research with fundamental messages to take forward. Dave has fun with the children in an everyday setting. This is where clinical trials have fallen down."
Dave Sherratt can be contacted at Mowbray School ( 01677-422446)