The reinforcing signal as a conditioned stimulus in human operant discrimination training

We demonstrated that subjects are capable of forming an on-off discrimination based on the fact that they are presented with periods of response-contingent reinforcement discriminable from periods of no such reinforcement. Four groups of 16 college students were run in a double-blind free-operant eyeblink conditioning experiment. Group designation was determined by whether the subject was an experimental or yoked control and whether he was provided with an external signal (S+, a red light) for on periods. Results indicated a significant degree of discrimination in both experimental groups when compared with operant periods and/or yoked controls. Contrary to expectation, no statistically significant advantage accrued to the subjects provided the light signal. Discussion considers the implication of this type of discrimination as an experimental control and conditions under which the provision of S+ should lead to greater advantage.