Encoding context and false recognition memories

False recognition of an extralist word that is thematically related to all words of a study list may reflect internal activation of the theme word during encoding followed by impaired source monitoring at retrieval, that is, difficulty in determining whether the word had actually been experienced or merely thought of. To assist source monitoring, distinctive visual or verbal contexts were added to study words at input. Both types of context produced similar effects: False alarms to theme-word (critical) lures were reduced; remember judgements of critical lures called old were lower; and if contextual information had been added to lists, subjects indicated as much for list items and associated critical foils identified as old. The visual and verbal contexts used in the present studies were held to disrupt semantic categorisation of list words at input and to facilitate source monitoring at output.     

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.     

Simultaneous paired associate and verbal discrimination learning as a simulation of the double-function list

In the critical condition, the subject was required to learn associations between words in the pairs and to learn to identify simultaneously the word in each pair that had been underlined on study trials. Over trials, both types of responding were required for each pair. Control conditions were used to assess the influence of these procedures. Paired associate learning was only modestly impaired, but the verbal discrimination learning (identifying the underlined word) appeared comparable to that for a double-function verbal discrimination list. The correlational evidence indicated that insofar as the present procedures simulated a double-function list, the association between the words in a pair is not involved in a causal way for the small amount of learning that occurs across trials in a double-function list.     

False recognition without intentional learning

Asked to memorize a list of semantically related words, participants often falsely recall or recognize a highly related semantic associate that has not been presented (the critical lure). Does this false memory phenomenon depend on intentional word reading and learning? In Experiment 1, participants performed a color identification task on distractor words from typical false memory lists. In Experiment 2, participants read the same words. In both experiments, the primary task was followed by a surprise recognition test for actually presented and unpresented words, including the critical lures. False alarms to critical lures were robust and quite equivalent across the two experiments. These results are consistent with an activation/monitoring account of false memory, in which processing of semantic associates can evoke false memories even when that processing is incidental.     

Part-list cuing and the dynamics of false recall

False recall of an unpresented critical word after studying its semantic associates can be reduced substantially if the strongest and earliest-studied associates are presented as part-list cues during testing (Kimball & Bjork, 2002). To disentangle episodic and semantic contributions to this decline in false recall, we factorially manipulated the cues’ serial position and their strength of association to the critical word. Presenting cues comprising words that had been studied early in a list produced a greater reduction in false recall than did presenting words studied late in the list, independent of the cues’ associative strength, but only when recall of the cues themselves was prohibited. When recall of the cues was permitted, neither early-studied nor late-studied cues decreased false recall reliably, relative to uncued lists. The findings suggest that critical words and early-studied words share a similar fate during recall, owing to selective episodic strengthening of their associations during study.     

Effects of talker, rate, and amplitude variation on recognition memory for spoken words

This study investigated the encoding of the surface form of spoken words using a continuous recognition memory task. The purpose was to compare and contrast three sources of stimulus variability--talker, speaking rate, and overall amplitude--to determine the extent to which each source of variability is retained in episodic memory. In Experiment 1, listeners judged whether each word in a list of spoken words was "old" (had occurred previously in the list) or "new." Listeners were more accurate at recognizing a word as old if it was repeated by the same talker and at the same speaking rate; however, there was no recognition advantage for words repeated at the same overall amplitude. In Experiment 2, listeners were first asked to judge whether each word was old or new, as before, and then they had to explicitly judge whether it was repeated by the same talker, at the same rate, or at the same amplitude. On the first task, listeners again showed an advantage in recognition memory for words repeated by the same talker and at same speaking rate, but no advantage occurred for the amplitude condition. However, in all three conditions, listeners were able to explicitly detect whether an old word was repeated by the same talker, at the same rate, or at the same amplitude. These data suggest that although information about all three properties of spoken words is encoded and retained in memory, each source of stimulus variation differs in the extent to which it affects episodic memory for spoken words.     

The influence of theme identifiability

In the present study, we used the Deese/Roediger-McDermott paradigm to analyze the relationship between theme identifiability of word lists and false memories in adults and children. We conducted two normative studies to determine the identifiability levels for critical unpresented words in 40 associative lists in adults and in 16 associative lists in children. Then, in three experiments, false memories for critical words that were either easy or hard to identify were analyzed in adults and in children 4–5 years old and 11–12 years old. Opposite results were found for adults and children. Lists with highly identifiable critical words produced fewer false memories for adults but more false memories for children. These results suggest that, if they can identify critical words, adults use an identify-to-reject strategy to edit out false memories, whereas, in children, theme identification does not lead to the use of such a monitoring strategy.     

False recognition following study of semantically related lists presented in jumbled word form

Three experiments explored a jumbled word effect in false recognition. Lists of theme-related items were presented in word or nonword form. Results indicated that critical lures semantically related to studied items were falsely recognised regardless of whether they were presented as words or nonwords. High false recognition rates to either SLEEP or SELEP following study of an appropriate theme list of items in nonword form should only occur if nonwords are recoded at study. With study conditions conducive to recoding, jumbled words induced false recognitions based on semantic associations among their respective base words. Disrupting a recoding process by creating "difficult" letter rearrangements for jumbled words (Experiment 2) appeared to eliminate the false recognition effect. In Experiment 3, presentation durations ranged from 110 ms to 880 ms. Although there was little evidence of a semantic false recognition effect at the fastest presentation rate, the brief durations appeared to be effective in eliminating the effect when items were studied in nonword form. These results appear to be consistent with an encoding activation/retrieval monitoring model.     

False recognition following study of semantically related lists presented in jumbled word form

Three experiments explored a jumbled word effect in false recognition. Lists of theme-related items were presented in word or nonword form. Results indicated that critical lures semantically related to studied items were falsely recognised regardless of whether they were presented as words or nonwords. High false recognition rates to either SLEEP or SELEP following study of an appropriate theme list of items in nonword form should only occur if nonwords are recoded at study. With study conditions conducive to recoding, jumbled words induced false recognitions based on semantic associations among their respective base words. Disrupting a recoding process by creating “difficult” letter rearrangements for jumbled words (Experiment 2) appeared to eliminate the false recognition effect. In Experiment 3, presentation durations ranged from 110 ms to 880 ms. Although there was little evidence of a semantic false recognition effect at the fastest presentation rate, the brief durations appeared to be effective in eliminating the effect when items were studied in nonword form. These results appear to be consistent with an encoding activation/retrieval monitoring model.     

Effect of task demands on dual coding of pictorial stimuli

Recent studies have suggested that verbal labeling of a picture does not occur automatically. Although several experiments using paired-associate tasks produced little evidence indicating the use of a verbal code with picture stimuli, the tasks were probably not sensitive to whether the codes were activated initially. It is possible that verbal labels were activated at input, but not used later in performing the tasks. The present experiment used a color-naming interference task in order to assess, with a more sensitive measure, the amount of verbal coding occurring in response to word or picture input. Subjects named the color of ink in which words were printed following either word or picture input. If verbal labeling of the input occurs, then latency of color naming should increase when the input item and color-naming word are related. The results provided substantial evidence of such verbal activation when the input items were words. However, the presence of verbal activation with picture input was a function of task demands. Activation occurred when a recall memory test was used, but not when a recognition memory test was used. The results support the conclusion that name information (labels) need not be activated during presentation of visual stimuli.     

Memory development in adolescence: Relationships between metamemory,strategy use,and performance

Eighth and tenth grade students were asked to study and recall a list of paired associates. The word pairs were available either throughout an 8 sec per word study period or only at the beginning and were composed of either high frequency or low frequency words. After recall, students were asked to indicate which of several study strategies they had used with each word pair (read pair carefully, rehearsal, visual elaboration, verbal elaboration). In addition, they were asked which of these strategies would have had the best effect on recall. Knowledge of appropriate memory strategies (metamemory) was positively related to strategy use, and strategy use was positively related to recall performance at both ages. Improved performance with materials available throughout study and with high frequency word pairs was explained by increased use of elaborative strategies. Age differences in performance were explained by increased strategy effectiveness. These results are discussed in relation to changing relationships among metamemory, strategy use, and performance with age.     

来源记忆中背景的情绪效价与唤醒对提取过程的影响

以往研究表明情绪背景对来源记忆存在影响,但背景的情绪效价和唤醒如何影响熟悉性及回想尚存争议。本研究以ERPs技术作为测量手段,采用来源记忆多键范式,操纵背景的情绪效价及唤醒强度,以探讨编码阶段背景情绪影响来源记忆提取的认知神经机制。学习阶段,呈现中性汉字及情绪图片（正性高唤醒、正性低唤醒、负性高唤醒、负性低唤醒）;测验阶段,仅呈现汉字,被试进行五键判断。行为结果发现：来源正确的比率比来源错误的比率更高,反应时更短;同时提取正性背景的辨别力更强,反应时更短;提取高唤醒背景反应时更短。脑电结果发现了分别代表熟悉性及回想的FN400及LPC新旧效应,且在500～700 ms,提取正性背景及高唤醒背景诱发显著更正的ERPs,但效价与唤醒没有交互作用。总体来说,来源记忆中背景效价及唤醒度对回想过程存在独立影响,体现为正性背景及高唤醒背景对来源提取的促进作用。     

Remembering words not presented in sentences: How study context changes patterns of false memories

People falsely endorse semantic associates and morpheme rearrangements of studied words at high rates in recognition testing. The coexistence of these results is paradoxical: Models of reading that presume automatic extraction of meaning cannot account for elevated false memory for foils that are related to studied stimuli only by their visual form; models without such a process cannot account for false memory for semantic foils. Here we show how sentence and list study contexts encourage different encoding modes and consequently lead to different patterns of memory errors. Participants studied compound words, such as tailspin and floodgate, as single words or embedded in sentences. We show that sentence contexts led subjects to be better able to discriminate conjunction lures (e.g., tailgate) from old words than did list contexts. Conversely, list contexts led to superior discrimination of semantic lures (e.g., nosedive) from old words than did sentence contexts.     

Intrusive effects of implicitly processed information on explicit memory

This study described the interference of implicitly processed information on the memory for explicitly processed information. Participants studied a list of words either auditorily or visually under instructions to remember the words (explicit study). They were then visually presented another word list under instructions which facilitate implicit but not explicit processing. Following a distractor task, memory for the explicit study list was tested with either a visual or auditory recognition task that included new words, words from the explicit study list, and words implicitly processed. Analysis indicated participants both failed to recognize words from the explicit study list and falsely recognized words that were implicitly processed as originating from the explicit study list. However, this effect only occurred when the testing modality was visual, thereby matching the modality for the implicitly processed information, regardless of the modality of the explicit study list. This "modality effect" for explicit memory was interpreted as poor source memory for implicitly processed information and in light of the procedures used. as well as illustrating an example of "remembering causing forgetting."     

Asymmetric Reinstatement Effects in Recognition

Our experiment examined two questions: (1) Does reinstating a studied context affect recognition of an associated word, and (2) Does reinstating a studied word affect recognition of an associated context? After encoding 75 words, each of which was shown superimposed over a different 5-sec video of an environment (e.g., a playground, a traffic scene, or a grocery store), participants were asked to recognize 50 of the words and 50 of the video scenes. On the test, half of the studied words were shown superimposed over the same video contexts that had been present at encoding, and half were shown over new scenes. Similarly, videos were presented with either old or new words. Context reinstatement increased hits and reduced false alarms for words, but word reinstatement did not affect recognition of video contexts. The results suggest that the associations that bind word events with their contexts may not be bidirectional.     

False recognition of associates: How robust is the effect?

False recognition of nonpresented words that were strong associates of 12 words in a study list was examined. Six lists were read to subjects; each list contained the 12 strongest associates to a critical nonpresented word. False-alarm rates to the 6 critical nonpresented words were obtained under several different conditions. The manipulations included varying the level of processing done to the study lists, varying the recognition-test procedure, repeating each of the study lists three times, and mixing the words from the six study lists together. A reliable false-recognition effect for critical nonpresented words was obtained in all conditions. However, the effect was not impervious to all of the manipulations. Significantly lower false recognition was obtained when learning was incidental as well as when the words on the six lists were mixed together. Neither level of processing nor repetition significantly influenced false recognition. This last result is inconsistent with Hintzman’s (1988) MINERVA 2 global memory model, but agrees with predictions from Shiffrin, Ratcliff, and Clark’s (1990) SAM model.     

Backward associative strength determines source attributions given to false memories

Source attributions for falsely remembered material were investigated in two experiments. A male and a female speaker each presented either an entire word list or half of the items from each of multiple Deese-Roediger-McDermott (DRM) lists commonly used in this paradigm. In the latter condition the tendency of each list half to activate a nonpresented, critical list theme item was manipulated. All of the list halves differed in backward associative strength (BAS), and each was presented by one or the other of the two speakers. In these correlated conditions, when critical items were falsely recognized (Experiments 1 and 2) or recalled (Experiment 2), source attributions were more frequently made to the speaker of the list items with the higher average BAS. This source attribution effect appears to result from the binding of list item source characteristics to activated critical items during encoding, as opposed to being the result of a biased retrieval process. The results are interpreted as consistent with an activation/monitoring account of false memory in the DRM paradigm.     

Norms for word lists that create false memories

Roediger and McDermott (1995) induced false recall and false recognition for words that were not presented in lists. They had subjects study 24 lists of 15 words that were associates of a common word (called the critical target or critical lure) that was not presented in the list. False recall and false recognition of the critical target occurred frequently in response to these lists. The purpose of the current work was to provide a set of normative data for the lists Roediger and McDermott used and for 12 others developed more recently. We tested false recall and false recognition for critical targets from 36 lists. Despite the fact that all lists were constructed to produce false remembering, the diversity in their effectiveness was large--60% or more of subjects falsely recalled window and sleep following the appropriate lists, and false recognition for these items was greater than 80%. However, the list generated from king led to 10% false recall and 27% false recognition. Possible reasons for these wide differences in effectiveness of the lists are discussed. These norms serve as a useful benchmark for designing experiments about false recall and false recognition in this paradigm.     

Recall accuracy and illusory memories: when more is less

In two experiments it was revealed that manipulations that increased recall of studied list items also increased false recall of theme-related, critical nonpresented words. In Experiment 1 subjects listened to a series of short word lists, each containing items associatively related to a theme, while engaging in either semantic or nonsemantic processing. On an immediate free recall test semantic processors demonstrated greater correct recall as well as more illusory memories of critical nonpresented items than nonsemantic processors. In Experiment 2, the short study lists were combined to form longer lists that were presented either blocked by theme or in a random presentation order. Retention interval was also varied as participants were tested either immediately, one week after, or three weeks after the study phase. Presenting the target items in a blocked, as opposed to random, format increased recall accuracy, but this was at the expense of a higher intrusion rate for theme-consistent items. Interestingly, the level of false memories was not affected by retention interval even though typical decrements in the recall of study items were observed over time. The results of these experiments highlight the persistence of the false memory effect, as well as pointing to several factors, primarily semantic processing, that may lead to the creation of false memories. Interpretations are offered within the theoretical frameworks of source monitoring and fuzzy trace theory.     

Verbal memory elicited by ambient odor.

This study examined whether an ambient odor can act as a contextual cue for retrieval of verbal stimuli. Subjects (N = 47) learned a list of 24 words while exposed to one of two odors (either jasmine incense or Lauren perfume) and subsequently relearned the list with either the same or the alternative odor present. Superior memory for the word list was found when the odor present during the relearning session was the same one that had been present at the time of initial learning, thereby demonstrating context-dependent memory. There were no differences in initial learning between the two odor conditions. No differences in pleasantness or intensity were found between the odors.