Semantic false memories in the form of derived relational intrusions following training

Contemporary behavior analytic research is making headway in characterizing memory phenomena that typically have been characterized by cognitive models, and the current study extends this development by producing "false memories" in the form of functional equivalence responding. A match-to-sample training procedure was administered in order to encourage participants to treat groups of unrelated English words as being interchangeable. Following training, participants were presented with a list of words from within one of the groups for a free recall test and a recognition test. Results showed that participants were more likely to falsely recall and recognize words that had been assigned to the same group as the list words during prior training, relative to words not assigned to the same group and relative to words that co-occurred with list words. These results indicate that semantic relatedness can be experimentally manipulated in order to produce specific false memories.     

Evidence that nonconscious processes are sufficient to produce false memories

Are nonconscious processes sufficient to cause false memories of a nonstudied event? To investigate this issue, we controlled and measured conscious processing in the DRM task, in which studying associates (e.g., bed, rest, awake...) causes false memories of nonstudied associates (e.g., sleep). During the study phase, subjects studied visually masked associates at extremely rapid rates, followed by immediate recall. After this initial phase, nonstudied test words were rapidly presented for perceptual identification, followed by recognition memory judgments. On the perceptual identification task, we found significant priming of nonstudied associates, relative to control words. We also found significant false recognition of these nonstudied associates, even when subjects did not recall this word at study or identify it at test, indicating that nonconscious processes can cause false recognition. These recognition effects were found immediately after studying each list of associates, but not on a delayed test that occurred after the presentation of several intervening lists. Nonconscious processes are sufficient to cause this memory illusion on immediate tests, but may be insufficient for more vivid and lasting false memories.     

When do false memories cross language boundaries in English—Spanish bilinguals?

To determine whether false memories cross language boundaries, we presented English-Spanish bilinguals with conceptually related word lists for five study-test trials. Some lists were heard in English, some in Spanish, and they were then followed by a recognition memory test composed of studied words, conceptually related nonstudied critical words, and unrelated words presented in the same language used at study or in a different language. Even though participants were instructed to recognize only previously heard words, they falsely recognized both same-language and different-language critical words. With practice, participants increased their accurate recognition of list words and decreased their false recognition of critical words when the study-test language was the same, and they decreased their false recognition of list words and critical words when the language differed. False memories can cross language boundaries when participants rely on conceptual representations from the word lists, but these errors decrease over trials as participants increasingly rely on language-specific lexical representations.     

Can test list context manipulations improve recognition accuracy in the DRM paradigm?

Only test-based manipulations can be used to help people distinguish accurate from false memories once events have been encoded. In two experiments we examined how the type of studied words (weak vs strong associates, or less vs more memorable associates) and nonstudied lure words (related vs unrelated lures) on the test list affect recognition accuracy in the Deese-Roediger-McDermott paradigm. False recognition of critical lures decreased substantially in the related-lure context, but so did correct recognition of studied words. False recognition was little affected by the studied-word manipulations. In general, participants claimed to recognise critical lures as often as weak associates or less memorable studied words but less often than either strong associates or more memorable studied words. The test-list context affected how participants classified their recognition experiences but it did not systematically change their overall memory accuracy.     

Can test list context manipulations improve recognition accuracy in the DRM paradigm?

Only test-based manipulations can be used to help people distinguish accurate from false memories once events have been encoded. In two experiments we examined how the type of studied words (weak vs strong associates, or less vs more memorable associates) and nonstudied lure words (related vs unrelated lures) on the test list affect recognition accuracy in the Deese-Roediger-McDermott paradigm. False recognition of critical lures decreased substantially in the related-lure context, but so did correct recognition of studied words. False recognition was little affected by the studied-word manipulations. In general, participants claimed to recognise critical lures as often as weak associates or less memorable studied words but less often than either strong associates or more memorable studied words. The test-list context affected how participants classified their recognition experiences but it did not systematically change their overall memory accuracy.     

Effects of divided attention and word concreteness on correct recall and false memory reports

Lists of thematically related words were presented to participants with or without a concurrent task. In Experiments 1 and 2, respectively, English or Spanish word lists were either low or high in concreteness (concrete vs abstract words) and were presented, respectively, auditorily or visually for study. The addition of a concurrent visual or auditory task, respectively, substantially reduced correct recall and doubled the frequency of false memory reports (nonstudied critical or theme words). Divided attention was interpreted as having reduced the opportunity for participants to monitor successfully their elicitations of critical associates. Comparisons of concrete and abstract lists revealed significantly more recalls of false memories for abstract than concrete word lists. Comparisons between two levels of attention, two levels of word concreteness, and two presentation modalities failed to support the "more is less" effect by which enhanced correct recall is accompanied by increased frequencies of false memories.     

Orthography,phonology, and meaning: Word features that give rise to feelings of familiarity in recognition

In the present study, it is shown that participants can recognize test cues as resembling studied words even when these cues cannot be used to recall the words that they resemble. After studying a list of words, participants were given a cued recall test for which half of the cues resembled studied words on one particular feature dimension and half resembled nonstudied words on that dimension. In addition to trying to use each cue to recall a study list item, participants rated the degree to which the cue resembled a studied word. For those cues whose targets could not be identified, the mean rating was higher when the cues corresponded to studied items than when they corresponded to nonstudied items. Various types of features can give rise to this phenomenon, which was found when orthographic, phonemic, and semantic cued recall tasks were used. In all of these cases of recognition without recall, analysis of receiver operating characteristics revealed a pattern consistent with that of an equal-variance signal detection process.     

What is the connection between true and false memories? The differential roles of interitem associations in recall and recognition.

Veridical memory for presented list words and false memory for nonpresented but related items were tested using the Deese/Roediger and McDermott paradigm. The strength and density of preexisting connections among the list words, and from the list words to the critical items, were manipulated. The likelihood of producing false memories in free recall varied with the strength of connections from the list words to the critical items but was inversely related to the density of the interconnections among the list words. In contrast, veridical recall of list words was positively related to the density of the interconnections. A final recognition test showed that both false and veridical memories were more likely when the list words were more densely interconnected. The results are discussed in terms of an associative model of memory, Processing Implicit and Explicit Representations (PIER 2) that describes the influence of implicitly activated preexisting information on memory performance.     

Creating false memories for brand names

Using the Deese–Roediger–McDermott (DRM) paradigm, participants are presented with lists of associated words (e.g., bed, awake, night etc). Subsequently, they reliably have false memories for related but non‐presented words (e.g. SLEEP). The present study investigated whether false memories could be created for brand names (e.g. Morrisons, Sainsbury's, Waitrose and TESCO) using the DRM paradigm and whether the effect was reduced if stimuli were presented in brand appropriate fonts compared with a plain font. Participants were presented with lists of brand names in plain or brand appropriate fonts, followed by a distractor task or free recall. Finally, they had a recognition task. Both false recall and false recognition of non‐presented brand names occurred. Brand specific fonts at study had no effect on recall but increased overall recognition. There was considerable variability in levels of false recall and false recognition amongst lists and across participants and reasons for this are discussed. Copyright © 2010 John Wiley & Sons, Ltd.     

Effects of free and forced retrieval instructions on false recall and recognition.

One hundred undergraduates heard 6 lists of 14 words that were each associated with 1 of 6 central concepts not on the lists (the DRMRS procedure). The participants were instructed to recall as many words as possible (free retrieval) or to fill all 14 spaces (forced retrieval) and were subsequently given a recognition test. False recall and recognition of the critical central concepts were higher with forced than with free retrieval instructions, but correct recall and recognition were not affected. Confidence was lower for false than for correct recall and recognition. Confidence was also lower with forced than with free retrieval instructions for false recall but not for false recognition. The DRMRS procedure easily elicited false memories, but confidence judgments helped more in detecting them in recall than in recognition. Theoretical and applied implications are discussed.     

Can false memories spontaneously recover?

Can false memories that were suppressed at one time spontaneously recover at a later time? Fuzzy trace theory and activation-monitoring theory predict that false memories in the Deese, Roediger, and McDermott (DRM) procedure become substantially reduced as list learning progresses because participants employ a memory-editing process. It follows that if the editing process is rendered less effective, false memories should spontaneously recover. We found that after DRM lists were well learned and false recognition to critical words was substantially reduced by multiple study–test trials, those false memories spontaneously recovered when participants were either rushed or delayed on a retest. We attributed the reduction in false recognition over trials to a memory-editing process that suppresses false recognition as participants gradually learn which words were in the lists and which words, though similar, were not. Rushing or delaying the participants on a retest made it more difficult for them to edit their memory, and false memories spontaneously returned.     

Variation in individuals' semantic networks for common knowledge is associated with false memory

Three experiments assessed the relationships between false memories of words and their degree of connectedness within individual semantic networks. In the first two experiments, participants studied associated word lists (e.g., hot, winter, ice), completed a recognition test that included related nonstudied words (e.g., cold, snow), and then rated the semantic relatedness of all word pairs including studied and nonstudied words. In the third experiment, the task order was reversed; participants completed pairwise ratings and then, two weeks later, completed the false memory task. The relatedness ratings were analysed using the Pathfinder scaling algorithm. In all experiments, items that an individual falsely recognized had higher semantic Pathfinder node densities than those items correctly rejected.     

Variation in individuals' semantic networks for common knowledge is associated with false memory

Three experiments assessed the relationships between false memories of words and their degree of connectedness within individual semantic networks. In the first two experiments, participants studied associated word lists (e.g., hot, winter, ice), completed a recognition test that included related nonstudied words (e.g., cold, snow), and then rated the semantic relatedness of all word pairs including studied and nonstudied words. In the third experiment, the task order was reversed; participants completed pairwise ratings and then, two weeks later, completed the false memory task. The relatedness ratings were analysed using the Pathfinder scaling algorithm. In all experiments, items that an individual falsely recognized had higher semantic Pathfinder node densities than those items correctly rejected.     

Acquired Equivalence Changes Stimulus Representations

Acquired equivalence is a paradigm in which generalization is increased between two superficially dissimilar stimuli (or antecedents) that have previously been associated with similar outcomes (or consequents). Several possible mechanisms have been proposed, including changes in stimulus representations, either in the form of added associations or a change of feature salience. A different way of conceptualizing acquired equivalence is in terms of strategic inference: Confronted with a choice on which it has no evidence, the organism may infer from its history of reinforcement what the best option is, and that inference is observed as acquired equivalence. To test this account, we combined an incremental learning task with an episodic memory test. Drawings of faces were made equivalent through acquired equivalence training, and then paired with words in a list learning paradigm. When participants were asked to recognize specific face-word pairings, they confused faces more often when they had been made equivalent. This suggests that prior acquired equivalence training does influence how memories are coded. We also tested whether this change in coding reflected acquisition of new associations, as suggested by the associative mediation account, or whether stimuli become more similar through a reweighting of stimulus features, as assumed by some categorization theories. Results supported the associative mediation view. We discuss similarities between this view and exemplar theories of categorization performance.     

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.     

False memories are hard to inhibit: differential effects of directed forgetting on accurate and false recall in the DRM procedure

Directed forgetting research shows that people can inhibit the retrieval of words that they were previously instructed to forget. The present research applied the directed forgetting procedure to the Deese/Roediger and McDermott (DRM) recall task to determine if directed forgetting instructions have similar or different effects on accurate and false memory. After studying lists of semantically related words, some participants were told to forget those lists, whereas other participants were not. All participants were then shown additional lists to remember. Following study, all participants were asked to free recall as many of the studied words as possible, including those they were previously instructed to forget. Directed forgetting instructions inhibited the accurate recall of studied words, but not the false recall of nonstudied critical words, whether measured by a within-participant or between-participants design. Contrary to an implicit activation hypothesis, false memories survived instructions to forget. These findings were reviewed in terms of fuzzy trace theory and the activation/monitoring approach to false memory.     

False and veridical collaborative recognition

Participants who witness an event and later receive post-event information that omits a critical scene are less likely to recall and to recognise that scene than are participants who receive no post-event information (Wright, Loftus, & Hall, 2001). The present study used the Deese-Roediger-McDermott (DRM) paradigm, in which participants study lists of semantic associates (e.g., hot, snow, warm, winter) that commonly elicit false memories of critical non-presented words (e.g., cold), to determine whether omitting information from a second presentation decreases memory for both presented and non-presented information. Participants were presented with a list of the semantic associates of six non-presented words. For half the participants, this list was presented a second time with the semantic associates of one of the non-presented words omitted. As expected, participants were less likely to recall and to recognise the presented words when they had been omitted from the second presentation. Omission also decreased the rate at which non-presented words were recalled, although false recognition of these words was not reduced. These results suggest that false recognition may be particularly difficult to attenuate and that post-event omission may be more detrimental to memory accuracy than previously thought.     

Omitting details from post-event information: are true and false memory affected in the same way?

Participants who witness an event and later receive post-event information that omits a critical scene are less likely to recall and to recognise that scene than are participants who receive no post-event information (Wright, Loftus, & Hall, 2001). The present study used the Deese-Roediger-McDermott (DRM) paradigm, in which participants study lists of semantic associates (e.g., hot, snow, warm, winter) that commonly elicit false memories of critical non-presented words (e.g., cold), to determine whether omitting information from a second presentation decreases memory for both presented and non-presented information. Participants were presented with a list of the semantic associates of six non-presented words. For half the participants, this list was presented a second time with the semantic associates of one of the non-presented words omitted. As expected, participants were less likely to recall and to recognise the presented words when they had been omitted from the second presentation. Omission also decreased the rate at which non-presented words were recalled, although false recognition of these words was not reduced. These results suggest that false recognition may be particularly difficult to attenuate and that post-event omission may be more detrimental to memory accuracy than previously thought.     

Forced fabrication versus interviewer suggestions: Differences in false memory depend on how memory is assessed

Many studies show that witnesses can develop false memories for suggested misinformation provided by an interviewer. The forced fabrication effect extends this finding by demonstrating that witnesses can also develop false memories for events they were forced to fabricate themselves. In two experiments we compared the incidence of false memory following forced fabrication and interviewer provided suggestion under various conditions (pre‐test warning/no warning; one‐week/two‐week delay) and type of test (source recognition vs. narrative recall). Whereas interviewer suggestions resulted in more false memories than forced fabrications on source recognition tests when participants overtly resisted fabricating and were warned at test, tests of narrative recall showed the opposite pattern even with pre‐test warnings: Fabrications generated following overt resistance led to more false recall than interviewer provided suggestions. This dissociation between suggestive interview type and test type indicates that predictions about the deleterious consequences of interviews are dependent on the way memory is assessed. Copyright © 2011 John Wiley & Sons, Ltd.     

The effects of social pressure on false memories

The present experiments were designed to examine the effects of social pressure on false memories. Participants studied lists created to elicit false memories and then worked in conjunction with virtual confederates on a recognition memory task. In Experiment 1, participants worked with one or two confederates to complete multiple study-test trials. On the group tests, participants were implicitly pressured to recognize words that did not appear on the studied lists. Experiment 2 was implemented similarly, but utilized a presumably more difficult recognition test involving one long study phase followed by one long test phase. After the purported group tests in both experiments, participants completed surprise individual recognition tests. In both experiments, social pressure influenced participants' responses on group recognition tests and subsequent individual recognition tests. Furthermore, the results indicated that social pressure affected both veridical memories and false memories.