Concept Definition: Trace Conditioning

Important characteristics of Trace Conditioning:

  • CS and US onsets are separated by an interval in which neither stimulus is present.
  • CR occurs shortly after CS onset, but with continued training CR moves closer in time to US onset.
  • As CS-US intervening interval increases, conditioning declines systematically.
graph showing that CS and US onsets are separated by a time interval in which neither stimulus is present

Consider the unconditioned reflex whereby food elicits (US) elicits salivation (UR). In Trace Conditioning, a tone (NS) might briefly sound several seconds before the food (US) is presented. The tone does not sound during the intervening interval. Consequently, the tone (CS) may come to elicit salivation (CR) even in the absence of food. With repeated conditioning trials, salivation may become increasingly delayed to the tone, occurring progressively closer in the time to food delivery. The eliciting effect of the tone may be less pronounced the longer the typical intervening interval between it and the food presentation.