Process dissociation procedure: Handle with caution!

Abstract

The process dissociation procedure (PDP) was introduced as a general-purpose tool for quantifying the extent to which performance on various cognitive tasks is mediated by consciously controlled versus automatic processes. In this paper, we consider several aspects that limit the procedure's domain of application. We suggest that the PDP is inappropriate for studying performance of implicit versus explicit memory tests because its focus on conscious versus automatic processes is different from the distinction between intentional versus non-intentional remembering that is targeted by implicit and explicit memory tests. We point out that the complexity of the instructions that are required for the procedure makes it unsuitable for use with special populations, such as amnesic patients. An examination of two core assumptions of the procedure (invariance of recollection and invariance of familiarity) revealed evidence suggesting that these assumptions are violated in many circumstances. In a final section, we introduce a more general model for quantifying consciously controlled versus automatic retrieval processes and show that the original PDP formulation is a special case that is obtained by making simplifying but probably unjustified assumptions. We hope that this paper will stimulate the development of more advanced and alternative investigative methods for dissociating processes.