Understanding the mechanisms behind deficits in imitation: Do individuals with autism know 'what' to imitate and do they know 'how' to imitate?

► We address the question if imitation problems are caused by selection or correspondence problems. ► We review 7 possible hypotheses on the nature of imitation problems in autism. ► We describe the poor preferential attention to biological motion, poor ascription of intention to actions, poor transformation of perspectives and poor mapping of visual to motor information. ► We recommend that tasks should be constrained to target as few mechanisms as possible in given experiments.