This thesis is concerned with the effects of varying the intensity of one element of a compound stimulus while holding the other constant in an experiment employing Kamin’s (1964) design for showing the "perceptual or associative clock" in the conditioned emotional response situation. The question of whether Pavlovian "over- shadowing" or Hullian "summation" usually obtains during classical compound conditioning is examined. The major findings were (1) that the degree of blocking is a monotonic function of the intensity of the first conditioned element; (2) that rate of conditioning to a compound stimulus is a monotonic function of the intensity of the varied element; and (3) that Hullian summation is the usual case in compound conditioning but that Pavlovian overshadowing occurs when one element is relatively much weaker than the other in terms of speed of conditioning.

Master of Arts (MA)

Thesis