Unconscious Influences Of Memory Research Articles

Conscious and unconscious influences of memory: Temporal dynamics

Changes in the conscious and unconscious influences of memory over time were assessed in two experiments by using a variant of the process-dissociation procedure. In both experiments, performance on a stem-completion task was measured under both inclusion and exclusion instructions. Across the two experiments, there were four different retention intervals: 2 minutes, 2 days, 2 weeks, and 2 months. The results indicated that conscious influences decreased systematically across retention interval. In contrast, unconscious influences of memory in the absence of conscious influences increased between 2 minutes and 2 days, and then remained relatively stable from 2 days to 2 weeks to 2 months. These results stand in apparent contrast to those of McBride and Dosher (1999), which showed equal rates of forgetting for conscious and unconscious influences of memory on performance. The implications for models of the relation between conscious and unconscious influences of memory on performance are discussed.

The relationship between conscious and unconscious influences: Independence or redundancy?

Determining the relationship between conscious and unconscious influences is essential for obtaining valid estimates of the 2 types of influence. S. Joordens and P. M. Merikle (1993) recently argued that a redundancy relationship provides a plausible alternative to the independence model proposed by L. L. Jacoby, J. P. Toth, and A. P. Yonelinas (1993). In this article, the authors address Joordens and Merikle's concerns and still find the independence model preferable: First, the redundancy model requires the questionable assumption that a direct test (inclusion) is process pure. Second, results obtained with the independence model, but not with the redundancy model, converge with results from indirect tests. Finally, conclusions drawn from the independence model are in accordance with the theorizing that surrounds the concept of automaticity. Findings of task dissociations have been important for theorizing about both unconscious perception and unconscious influences of memory (implicit memory). People show evidence of perception and memory on indirect tests although they are seemingly unaware of the event that gave rise to those effects when given a direct test (e.g., Roediger & McDermott, 1993). However, Reingold and Merikle (1990), as well as we (Jacoby, Toth, & Yonelinas, 1993) have argued against the practice of equating unconscious influences with performance on indirect or implicit tests and conscious influences with performance on direct or explicit tests. The difficulty is that conscious processes might contaminate performance on indirect tests and, less obviously, unconscious processes might contaminate performance on direct tests. Consequently, we have sought process dissociations rather than task dissociations. That is, rather than equating processes with tasks, our strategy has been to gain estimates of the contributions of conscious and unconscious processes to performance of a single task and to show dissociations of effects of variables on those estimates.

Separating conscious and unconscious influences of memory: Measuring recollection.

How can conscious and unconscious influences of memory be measured? In this article, a processdissociation procedure (L. L. Jacoby, 1991) was used to separate automatic (unconscious) and consciously controlled influences within a task. For recall cued with word stems, automatic influences of memory (a) remained invariant across manipulations of attention that substantially reduced conscious recollection and (b) were highly dependent on perceptual similarity from study to test. Comparisons with results obtained through an indirect test show the advantages of the process-dissociation procedure as a means of measuring unconscious influences. The measure of recollection derived from this procedure is superior to measures gained from classic test theory and signal-detection theory. The process-dissociation procedure combines assumptions from these 2 traditional approaches to measuring memory. Dissociations between performance on direct and indirect tests of memory supply examples of effects of the past in the absence of remembering (for reviews, see Hintzman, 1990; Richardson-Klavehn & Bjork, 1988). In an indirect test, subjects are not asked to report on memory for an event as they would be in a direct test, such as in a test of recognition or recall; rather, they engage in some task that can indirectly reflect memory for the occurrence of that event. Word stemand fragment-completion tasks are among the most popular indirect tests of memory (e.g., Graf & Mandler, 1984; Tulving, Schacter & Stark, 1982; Warrington & Weiskrantz, 1974). For a stem-completion task, subjects might read the word scalp and then be presented with the stem sea— with instructions to complete that stem with the first word that comes to mind. Evidence of automatic influences of memory that are dissociated from performance on a direct test is provided by the finding that prior presentation of a word increases the likelihood of that word being used to complete a stem, even though a direct test reveals no memory for the prior presentation of the word. Some of the most striking examples of dissociations come from the performance of patients suffering a neurological deficit. Korsakoff amnesics, for example, show near-normal effects of memory in their performance of a stem-completion task, even though

Separating conscious and unconscious influences of memory: Measuring recollection.

Separating conscious and unconscious influences of memory: Measuring recollection.