CHAINS: A QUICKBASIC 4.5 PROGRAM FOR STUDYING VARIABLES AFFECTING HUMAN LEARNING

The procedure known as "the repeated acquisition of behavioral chains" has revealed how learning is affected by variables such as the punishment of errors (Boren & Devine, 1968), drugs (Higgins, Rush, Hughes, Bickel, Lynn, & Capeless, 1992; Thompson & Moerschbaecher, 1979), and age (Perone & Baron, 1982). In each session, a participant learns a sequence of responses ("the chain") that produces reinforcement. The sequences differ between sessions, but with extended practice the participant's error rate stabilizes and provides a baseline for studying variables affecting learning. CHAINS, a QuickBASIC 4.5 (QB4.5) program, modeled after procedures used by Perone and Baron (1982), allows researchers with some knowledge of BASIC to easily implement the repeated acquisition procedure with humans. CHAINS first instructs the participant that depressing the correct sequence of numeric keys on the number pad produces a reinforcer. Depressing a correct key displays the corresponding numeral on the screen and sounds a high frequency tone. Depressing an incorrect key or responding late momentarily deactivates the keyboard ("timeout" from the opportunity to earn reinforcement) and sounds a low frequency tone. When the participant completes the correct sequence, depressing the "ENTER" key produces a whistling sound that signals a reinforcer has been earned. Subsequently, the screen is cleared and the participant can re-enter the sequence. Over sessions, participants become proficient at entering sequences, despite the sequence changing between sessions, and their error rates stabilize. At this point interventions such as drugs, distraction, or music may be introduced and withdrawn to determine, for each individual