Pretend Play in Signing Chimpanzees (Pan troglogytes)

Pretend play is well studied in human children and is thought to be associated with symbolic thought and theory of mind. There are many descriptions of pretend play in chimpanzees and other apes but few systematic studies. This study was a systematic sampling of videotapes for instances of pretend play in chimpanzees who have acquired American Sign Language. There were two sampling methods. The first sample of 17 hours 36 minutes and 26 seconds of videotape contained five instances of pretend play. The second sample of 50 hours 16 minutes and 41 seconds contained 16 instances. The instances fell into four different categories; substitution, attribution of function, animation, and insubstantial situation attribution