B.F. Skinner (1937)
First published in Journal of General Psychology, 16, 272-279.
Before considering the specific objections raised by Konorski and Miller(4) against my formulation of a second type of conditioned reflex, I should like to give a more fundamental characterization of both types and of the discriminations based upon them. Let conditioning be defined as a kind of change in reflex strength where the operation performed upon the organism to induce the change is the presentation of a reinforcing stimulus in a certain temporal relation to behavior. All changes in strength so induced come under the head of conditioning and are thus distinguished from changes having similar dimensions but induced in other ways (as in drive, emotion, and so on). Different types of conditioned reflexes arise because a reinforcing stimulus may be presented in different kinds of temporal relations. There are two fundamental cases: in one the reinforcing stimulus is correlated temporally with a response and in the other with a stimulus. For "correlated with" we might write "contingent upon". There are the types that I have numbered I and II respectively. Konorski and Miller refer to the second as Type I and to a complex case involving the first (see below) as Type II. To avoid confusion and to gain a mnemonic advantage I shall refer to conditioning which results from the contingency of a reinforcing stimulus upon a stimulus [p.273] as a Type S and to that resulting from contingency upon a response as of Type R. If the stimulus is already correlated with a response or the response with a stimulus, a reinforcement cannot be made contingent upon the one term without being put into a similar relation with the other. That is to say, if a reinforcing stimulus is correlated temporally with the S in a reflex, it is also correlated with the R, or if with the R, then also with the S. It is not
References: (1) Hudgins, C. V. Conditioning and the voluntary control of the pupillary reflex. J. Gen. Psychol., 1933, 8, 3-51. (2) Skinner, B. F. Two types of conditioned reflex and a pseudo type. J. Gen. Psychol., 1935, 12, 66-77. (3) ----------. The rate of establishment of a discrimination. J. Gen. Psychol., 1933, 9, 302-350. (4) Konorski, J. A., & Miller, S. M. On two types of conditioned reflex. J. Gen. Psychol., 1937, 16, 264-272.