 A defining feature of autism is a global impairment in ones ability to learn. Repeated acquisition tasks are commonly used in drug behavioral pharmacology studies to assess the effect of a drug on the ability of an individual to learn, that is, the efficiency with which the individuals behavior is brought under new forms of stimulus control. Repeated acquisition tasks typically involve the participant learning to respond to a new sequence of positions during each session. For example, four levers or buttons are presented and the participant must press the four buttons in a particular sequence in order to earn reinforcement. However, the correct sequence is different for every session, and typically one session is conducted daily, so the sequence of responding required to earn reinforcement is different each day. The performance of the participant can be analyzed in a number of ways including the percent correct for the entire session, the total number of responses or the number of errors made until 80 correct responding is reached. 