SPENCE, K W EFFECT OF A NUMBER OF ACQUISITION TRIALS AND THE PRESENCE OR ABSENCE OF THE UCS ON EXTINCTION OF THE EYELID CR. [electronic resource] - Journal of experimental psychology Sep 1963 - 286-91 p. digital Publication Type: Journal Article ISSN: 0022-1015 Standard No.: 10.1037/h0039913 doi Subjects--Topical Terms: Conditioning, PsychologicalExtinction, PsychologicalEyelidsHumansReinforcement, Psychology