Procedurally, sensory preconditioning involves repeated simultaneous presentations (pairing) of two neutral stimuli (NS, e.g. a light and a tone), i.e. stimuli that are not associated with a desired unconditioned response (UR, e.g. salivation).
The term "sensory preconditioning" was coined by W. J. Brogden in 1939 at Johns Hopkins University.
[1][2] During the first stage of a sensory preconditioning procedure, two neutral stimuli (NS1 and NS2) are paired together either simultaneously or serially.
A forward conditioning experiment using a between-subjects design, followed by CS1 extinction suggests the possibility of an S-S pathway (Rizley and Rescorla, 1972).
However, in this sensory preconditioning experiment the extinction of CS1 transferred to CS2, suggesting an associative chain explanation whereby CS2-->CS1-->UCS-->Response.