Abstract
People with Pervasive Developmental Disorders (PDD) have a different culture from ours. In order that they may live a useful life, it is necessary for us to understand their cognitive characteristics correctly and help them to communicate successfully with others from an early stage, since they are of the minority and are in a disadvantageous position in the world. Visual cues for communication are of help to autistic people, just as glasses are to the short-sighted and canes are to the physically-handicapped, and so we should notice their handicap and start to give them necessary help at an early stage. It is suggested that this is the significance of early diagnosis for PDD.
