Kimmel H D
Am J Psychol. 1977 Jun;90(2):319-21.
Sensory preconditioning was first demonstrated in Pavlov's laboratory in 1931/32, rather than discovered by Brogden in 1939. Pavlov included nonassociative controls, forward pairing of the indifferent stimuli before reinforcing the second one with shock, and he avoided the development of inhibition to the compound by using a moving visual stimulus and a sound like that of scurrying mice, which both had persistent orienting reactions. Pavlov concluded that the indifferent stimuli were associated by temporal contiguity similar to human associations between successively spoken works. He did not consider the possibility of mediation via the orienting reactions.