A complex features account of the occasion setting effect

The findings of transferability and irreversibility of stimulus function following occasion setting training have been detrimental to compound-stimulus accounts of the occasion setting effect. The purpose of the experiment was to demonstrate that those data which have supported the existence of an occasion setting stimulus function are predictable and interpretable in terms of one version of a compound-stimulus account, the complex features model. A basic assumption of the complex features model is that all stimuli contain obvious and nonobvious features which become conditioned exciters or inhibitors according to the same set of principles which describes all Pavlovian stimulus control. Successful transfer and reversal following occasion setting training will be possible to the extent that the evocative features of the trained occasion setting compound are present in the tested compounds as well. Arranging contingencies favorable for transfer or reversibility requires only that the training procedure itself be arranged in such a way that features common to the training and test compounds are made more evocative than any features exclusive to the training compound, without also disrupting the occasion setting effect