We focus on the issue of whether cognitive effort is causally related to memory. We begin with a discussion of the concept of cognitive effort as derived from capacity models of attention. We then suggest that the theoretical analysis of memory may involve concepts from different levels of psychological analysis, and we draw a distinction between concepts that represent boundary conditions and sufficient cause. When applied to memory phenomena, attentional concepts serve only as a boundary-or limiting-function in memory theory. In contrast, concepts that represent memorial processes serve as a sufficient cause function. In some instances, cognitive effort appears to have been used as a sufficient cause concept, resulting in some confusion. A review of the literature reveals a haphazard correlation between indexes of cognitive effort and of memory performance. Alternatively, the application of cognitive effort or capacity to the memory performance of certain populations (clinical, children, and elderly) illustrates a potentially more appropriate use of the concept.Whatever future conclusion we may reach as to this, we cannot denythat an object once attended to will remain in the memory, whilst one inattentively allowed to pass will leave no traces behind. (James, 1890, p. 427) The conceptsof attentionand memory have been perennially interwoven in the fabric of cognitive theory. Any adequate theory of intellectual functioning must eventually describe the interaction between these concepts, as well as provide a coherent account of the two concepts separately. Research and theory on these concepts logically precede description of their interaction, but the inextricable intertwining of attention and memory sometimes encourages the transfer of concepts from attention to explanations of memory. Since theories of attentionand theories of memory, as separate conceptual systems, are designed to address different questions, borrowing concepts from attention to explain questions about memory can lead to confusion and, occasionally, to illogical propoThis article is based in part on a symposium at the 91st Annual Convention of the American Psychological Association in Anaheim, CA (Hunt, 1983 sitions. It is our position that some conceptual confusion has arisen over the application of the attentional concept of cognitive effort as an explanatory mechanism of memory phenomena.The goal of a theory of attention, in large part, is to describe the selective and limited character of cognitive functioning. The empiricalbasis for this work has derived historically from the question, "How many things can be done at one time?" Dependentmeasures of memory have often been used to answer this empirical question. Memory measures are prevalent in empirical studies of attention because theories of attention typically specify a mechanism for selection, and memory performance can be predicted from the hypotheticaloperation of this selection mechanism. For example, Broadbent's (1958)model of attention assumed that the processes responsible f...