Preilowski, B., Reger, M., Engele, H. 1988. Combining scientific experimentation with conventional housing: A pilot study with rhesus monkeys. American Journal of Primatology 14, 223-234.

The testing apparatus ... was connected to a computer that controlled the test and the distribution of regular monkey chow as reward. Manipulatory activity required by the apparatus reduced motor stereotypies but not self-biting in single-housed subjects.