David A. Gallo

Factors that determine false recall: A multiple regression analysis

In the Deese-Roediger-McDermott (DRM) paradigm, subjects study lists of words that are designed to elicit the recall of an associatively related critical item. The 55 lists we have developed provide levels of false recall ranging from .01 to .65, and understanding this variability should provide a key to understanding this memory illusion. Using a simultaneous multiple regression analysis, we assessed the contribution of seven factors in creating false recall of critical items in the DRM paradigm. This analysis accounted for approximately 68% of the variance in false recall, with two main predictors: associative connections from the study words to the critical item (r+.73; semipartialr+.60) and recallability of the lists (r+.43; semipartialr-.34). Taken together, the variance in false recall captured by these predictors accounted for 84% of the variance that can be explained, given the reliability of the false recall measures (r=.90). Therefore, the results of this analysis strongly constrain theories of false memory in this paradigm, suggesting that at least two factors determine the propensity of DRM lists to elicit false recall. The results fit well within the theoretical framework postulating that both semantic activation of the critical item and strategic monitoring processes influence the probability of false recall and false recognition in this paradigm.

False memories and fantastic beliefs: 15 years of the DRM illusion

This article reviews research using the Deese/Roediger—McDermott (DRM) associative memory illusion, whereby people falsely remember words that were not presented. This illusion has broadly influenced basic theories of memory in cognitive psychology and neuroscience and naturally raises the question as to how these theories apply to more complex autobiographical memories. Some applicability is evident from research linking individual differences in the DRM illusion to false autobiographical memories (e.g., misremembering public events) and fantastic autobiographical beliefs (e.g., memories from past lives). But which aspects generalize? Here it is argued that a process—oriented approach is needed in order to answer this question. Many productive years of DRM research indicate that multiple and often opposing psychological processes cause even the most basic false memories. In light of these discoveries, more researchers need to use methods that isolate these component processes if the goal is to understand false memories both in the lab and in life.

Remembering words not presented in lists: Can we avoid creating false memories?

Can subjects avoid creating false memories as outlined in Roediger and McDermott’s (1995) false recognition paradigm if they are forewarned about this memory illusion? We presented subjects with semantically related word lists, followed by a recognition test. The test was composed of studied words, semantically related nonstudied words (critical lures), and unrelated nonstudied words. One group of subjects was uninformed about the false recognition effect, a second group was urged to minimize all false alarms, and a third group was forewarned about falsely recognizing critical lures. Compared with the uninformed and cautious subjects, the forewarned subjects reduced their false alarm rate for critical lures, and they made remember and know judgments equally often for recognized studied words and critical lures. But forewarning did not eliminate the false recognition effect, as these subjects and those in the other groups made numerous false recognitions in this task.

Associative false recognition occurs without strategic criterion shifts

In the DRM (Deese/Roediger and McDermott) false memory paradigm, subjects studied lists of words associated with nonpresented critical words. They were tested in one of four instructional conditions. In a standard condition, subjects were not warned about the DRM Effect. In three other conditions, they were told to avoid false recognition of critical words. One group was warned before study of the lists (affecting encoding and retrieval processes), and two groups were warned after study (affecting only retrieval processes). Replicating prior work, the warning before study considerably reduced false recognition. The warning after study also reduced false recognition, but only when critical items had never been studied; when critical items were studied in half the lists so that subjects had to monitor memory for their presence or absence, the warning after study had little effect on false recognition. Because warned subjects were trying to avoid false recognition, the high levels of false recognition in the latter condition cannot be due to strategically guessing that critical test items were studied. False memories in the DRM paradigm are not caused by such liberal criterion shifts.

Hypoxia-inducible factor 1α stabilization by carbon monoxide results in cytoprotective preconditioning

The most salient feature of carbon monoxide (CO)-mediated cytoprotection is the suppression of inflammation and cell death. One of the important cellular targets of CO is the macrophage (mφ). Many studies have shown that exposure of mφ to CO results in the generation of an antiinflammatory phenotype; however, these reports have ignored the effect of CO alone on the cell before stimulation. Most investigations have focused on the actions of CO in modulating the response to noxious stimuli. We demonstrate here that exposure of mφ to CO results in a significant and transient burst of reactive oxygen species (ROS) arising from the mitochondria (mitochondria-deficient mφ do not respond to CO to produce ROS). The ROS promote rapid activation and stabilization of the transcription factor hypoxia-inducible factor 1α (HIF-1α), which regulates expression of genes involved in inflammation, metabolism, and cell survival. The increase in HIF-1α expression induced by CO results in regulated expression of TGF-β, a potent antiinflammatory cytokine. CO-induced HIF-1α and TGF-β expression are necessary to prevent anoxia/reoxygenation-induced apoptosis in mφ. Furthermore, blockade of HIF-1α using RNA interference and HIF-1α-cre-lox mφ resulted in a loss of TGF-β expression and CO-induced protection. A similar mechanism of CO-induced protection was operational in vivo to protect against lung ischemia-reperfusion injury. Taken together, we conclude that CO conditions the mφ via a HIF-1α and TGF-β-dependent mechanism and we elucidate the earliest events in mφ signaling that lead to and preserve cellular homeostasis at the site of injury.

Creating False Memories of Words With or Without Recognition of List Items: Evidence for Nonconscious Processes

Subjects exposed to lists of semantically related words falsely remember nonstudied words that are associated with the list items (e.g., Deese, 1959; Roediger & McDermott, 1995). To determine if subjects would demonstrate this false memory effect if they were unable to recognize the list items, we presented lists of semantically related words with or without a concurrent memory load at rates of 2 s, 250 ms, or 20 ms per word (Experiment 1, between-subjects design) and 2 s or 20 ms per word (Experiment 2, within-subjects design). We found that the subjects falsely recognized semantically related nonstudied words in all conditions, even when they were unable to discriminate studied words from unrelated nonstudied words. Recognition of list items was unnecessary for the occurrence of the false memory effect. This finding suggests that this memory illusion can be based on the nonconscious activation of semantic concepts during list presentation.

Processing approaches to cognition: The impetus from the levels-of-processing framework

Processing approaches to cognition have a long history, from act psychology to the present, but perhaps their greatest boost was given by the success and dominance of the levels-of-processing framework. We review the history of processing approaches, and explore the influence of the levels-of-processing approach, the procedural approach advocated by Paul Kolers, and the transfer-appropriate processing framework. Processing approaches emphasise the procedures of mind and the idea that memory storage can be usefully conceptualised as residing in the same neural units that originally processed information at the time of encoding. Processing approaches emphasise the unity and interrelatedness of cognitive processes and maintain that they can be dissected into separate faculties only by neglecting the richness of mental life. We end by pointing to future directions for processing approaches.

Using recall to reduce false recognition: diagnostic and disqualifying monitoring.

Whether recall of studied words (e.g., parsley, rosemary, thyme) could reduce false recognition of related lures (e.g., basil) was investigated. Subjects studied words from several categories for a final recognition memory test. Half of the subjects were given standard test instructions, and half were instructed to use recall to reduce false recognition. Manipulation checks indicated that the latter instructions did elicit a recall-to-reject strategy. However, false recognition was selectively reduced only when all the words from a category could be recalled (Experiment 1). When longer categories were used, thereby minimizing exhaustive recall, a recall-to-reject strategy was ineffective at reducing false recognition (Experiment 2). It is suggested that exhaustively recalling a category allowed subjects to disqualify the lure as having occurred, analogous to recall-to-reject demonstrations in other tasks. In contrast, partially recalling a category did not help to diagnose the lure as nonstudied. These findings constrain theories of recall-based monitoring processes.

Associative Recognition in Alzheimer's Disease: Evidence for Impaired Recall-to-Reject.

Patients with mild Alzheimers disease (AD) were compared with age-matched control subjects on an associative recognition task. Subjects studied pairs of unrelated words and were later asked to distinguish between these same studied pairs (intact) and new pairs that contained either rearranged studied words (rearranged) or non-studied words (non-studied). Studied pairs were presented either once or 3 times. Repetition increased hits to intact pairs in both groups, but repetition increased false alarms to rearranged pairs only in patients. This latter pattern indicates that repetition increased familiarity of the rearranged pairs, but only the control subjects were able to counter this familiarity by recalling the originally studied pairs (a recall-to-reject process). AD impaired this recall-to-reject process, leading to more familiarity based false alarms. These data support the idea that recollection-based monitoring processes are impaired in mild AD.

The effects of associations and aging on illusory recollection

Younger and older adults (mean years=20.5 and 75) studied lists of associated words for a final recognition test. The length (5, 10, or 15 associates) and modality (auditory or visual) of study lists were manipulated within subjects. For both groups, increasing the number of associates increased illusory recollections of a related lure’s presentation (measured by source judgments and the Memory Characteristics Questionnaire). This pattern suggests that associative activation of the lure influenced illusory recollection, and aging spared this process. In contrast, age impaired the recollection of source for studied words (auditory or visual) and had identical effects on source attributions for related lures. This pattern suggests that the true recollection of source influenced illusory recollection of source, and age impaired this process. To account for these and other results, we propose that associative activation drives an attribution process that binds subjectively detailed features to a false memory.