Play embraces children's total experience. The Start Right Document on Nursery Education laid down that 'play is the serious work of childhood'. The play is thus continually moving and creative, and with endless educational content. Children who show the greatest capacities for social make-believe play also display more imagination and have less aggression. In The Importance of Play, a report on the value of children's play, Dr David Whitebread writes: The evolutionary and psychological evidence points to the crucial contribution of play in humans to our success as a highly adaptable species. Playfulness is strongly related to cognitive development and emotional well-being. Play requires imagination and fantasy, the very foundations of flexibility and creativity which also promote self-confidence and self-esteem. Visitors to a Steiner kindergarten are always surprised at what they see as a 'lack' of playthings for the children. Many children experience what could be called 'boredom' at this age.