Perceptual learning transfer: Salience of the common element as a factor contributing to the intermixed/blocked effect.

Rats received intermixed or blocked preexposure to 2 similar flavor compounds, AX and BX. Following preexposure, conditioning trials took place in which a novel compound stimulus NX was paired with an illness-induced unconditioned stimulus. Animals that were given intermixed preexposure to AX and BX showed lower generalization of the aversive response conditioned to NX to a new compound, ZX, than animals that were given blocked preexposure. The results support the proposal that intermixed preexposure reduces the salience of the common element X to a greater extent than blocked preexposure. The way in which current theories of perceptual learning can predict a differential salience of X after intermixed and blocked preexposure is discussed.