Procedures involving reversal learning can also index the ability of subjects to selectively withhold conditioned responses during learning.31 These tasks usually consist of a phase in which subjects are trained on a set of stimulus-outcome or response-outcome associations. After the initial association is learned, the trained contingencies are unexpectedly changed, or reversed, and subjects must then learn to selectively inhibit the previously reinforced response in order to avoid punishment and/or obtain reward. High rates of responding to the originally trained association are considered to be one index of impulsive (or perhaps compulsive) action.
