Narrowing down the conditions for extinction of Pavlovian feature-positive discriminations in humans.

The aim of this study was to delineate the minimal conditions for extinction of Pavlovian modulation in humans. Previous experiments at our lab showed that, after X ➔ A+/A- acquisition training, X- trials did not extinguish differential X ➔ A+/A- responding, while X ➔ A- trials did. Additionally, X ➔ A- extinction training seemed only to extinguish differential X ➔ A+/A- responding, while leaving differential responding on a concurrently trained Y ➔ B+/B- discrimination intact. It thus seemed that the X ➔ A+/A- discrimination can only be extinguished by X ➔ A- extinction trials. (Rescorla, Journal of Experimental Psychology: Animal Behavior Processes 12, 16-24, ), on the other hand, found that the minimal conditions for extinction were broader in pigeons: Namely, he found that an acquired X ➔ A+/A- discrimination could be extinguished by presenting the original feature X in combination with a different target (B) that was minimally trained as an exciter. We thus wanted to examine whether this was also the case in humans. We found that nonreinforced X ➔ B- presentations did not abolish discriminative X ➔ A/A responding when target B was a nonreinforced stimulus. Nonreinforced X ➔ B- trials did extinguish the X ➔ A+/A- discrimination when target B had previously been trained as a target for modulation (X ➔ B+/B- or Y ➔ B+/B- training) or as a reinforced exciter (B+). Our results thusf parallel and extend those in nonhuman animals (Rescorla, Journal of Experimental Psychology: Animal Behavior Processes 12, 16-24, ). [ABSTRACT FROM AUTHOR]