“…The method in these experiments consisted of giving a low dose of a drug, paired with a subsequent larger dose of the same drug. These studies have demonstrated acquisition and extinction effects when the low dose of the drug served as the CS (Cepeda-Benito & Short, 1997;Greeley, Lê, Poulos, & Cappell, 1984;Kim, Siegel, & Patenall, 1999;Sokolowska, Siegel, & Kim, 2002). However, these experiments have not compared the relative effectiveness of arbitrary versus drug cues as signals for subsequent drug administration and have not examined such manipulations as blocking, CS-US interval effects, or second-order conditioning.…”