It is possible that autistic children are not neurophysiologically abnormal but children with hearing hyperacuity, born into an environment that cannot adapt to them. If so, to them, human sounds are not soothing but frightening. Environmental noises do not arouse curiosity but hurt so much the child withdraws. Because of self-imposed isolation, the child's brain hungers for stimulation, increasing the level of arousal which results in an anxietyevoking experience of sound in addition to pain. Parents mistake the withdrawal as a signal for them to try to communicate more vigorously thereby increasing the child's fear of them. Parents eventually learn to remain cool and aloof but this deprives the child of alternate forms of stimulation. The net result is an information-deprived brain, an inability to interpret auditory symbols and, eventually, irreversible retardation.