During first few days of life an infant can imitate actions or facial gestures of adults (e.g., stick out tongue in copying of adult). By 18 months can imitate and completed observed human actions (e.g., pulling apart a toy dumbbell) but will ignore the same actions if carried out by a mechanical device. (Restak, Richard, MD. The New Brain. PA: Rodale, 2003, pp 34-35)