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.     

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.     

The role of test structure in creating false memories

In the Deese/Roediger-McDermott (DRM) paradigm, studying lists of semantic associates results in high rates of false recognition of a nonpresented critical word. The present set of experiments was designed to measure the contribution of additional processing of list items at test to this false memory effect. The participants studied sets of lists and then performed a recognition task for each set. In three experiments, using this paradigm, we investigated false recognition when the number of studied list items presented at test (0, 6, or 12) was manipulated. In Experiments 2 and 3, false recognition of critical lures associated to both studied and nonstudied lists increased significantly as the number of list items included in the test increased. These results indicate that processes occurring at retrieval contribute to false memory effects found with the DRM paradigm.     

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.     

The Roles of Semantic and Phonological Information in Word Production: Evidence from Spanish–English Bilinguals

The research investigated the roles of semantic and phonological processing in word production. Spanish–English bilingual individuals produced English target words when cued with definitions that were also written in English. When the correct word was not produced, a secondary task was performed in which participants rated the ease of pronunciation of a Spanish prime word. We varied the relatedness between target and prime words. In related conditions, the target and prime words were cognates (i.e., similar in meaning and sound), false cognates (i.e., similar in sound, but different in meaning), or noncognates (i.e., similar in meaning, but different in sound). In unrelated conditions, target and primes were dissimilar in sound and meaning. The results showed that participants’ performance was influenced by semantic as well as phonological information. These results provided evidence that semantic as well as phonological information can influence word production, as is predicted by memory models in which representations for semantic and phonological levels of representation are interconnected.     

Semantic satiation and lexical ambiguity resolution.

This study examines the effects of semantic satiation on lexical ambiguity resolution. On a given trial, participants were presented with a word triad. The first word (e.g., HEART) was presented on average 2.5, 12.5, or 22.5 times, and then participants received 2 new words for relatedness judgments. The first of the two new words was always a homograph (e.g., "ORGAN") and the other word was a related or unrelated pairmate (e.g., "KIDNEY"). In Experiment 1, when blocks of trials were intermixed with concordant (e.g., "HEART-ORGAN-KIDNEY"), discordant (e.g., "PIANO-ORGAN-KIDNEY"), and neutral (e.g., "CEILING-ORGAN-KIDNEY") trials, participants did not produce evidence of semantic satiation. In a second experiment in which only concordant and neutral trials were presented, however, participants did produce evidence of semantic satiation in the concordant condition. Taken together, Experiments 1 and 2 indicate that semantic satiation of the context-appropriate meaning of a homograph may impede ambiguity resolution.     

Dissociated developmental trajectories for semantic and phonological false memories

False recognition following presentation of semantically related and phonologically related word lists was evaluated in 8-, 11-, and 13-year-olds. Children heard lists of words that were either semantic (e.g., bed, rest, wake ...) or phonological associates (e.g., pole, bowl, hole ...) of a critical unpresented word (e.g., sleep, roll), respectively. A semantic false memory was defined as false recognition of a semantically related but unpresented word. A phonological false memory was defined as false recognition of a phonologically related but unpresented word. False memories in the two tasks showed opposite developmental trends, increasing with age for semantic relatedness and decreasing with age for phonological relatedness.     

Conceptual representation of verbs in bilinguals: semantic field effects and a second-language performance paradox

It is well known that bilinguals perform better in their first language (L1) than in their second lanaguage (L2) in a wide range of linguistic tasks. In recent studies, however, the authors have found that bilingual participants can demonstrate faster response times to L1 stimuli than to L2 stimuli in one classification task and the reverse in a different classification task. In the current study, they investigated the reasons for this "L2-better-than-L1" effect. English-French bilinguals performed one word relatedness and two categorization tasks with verbs of motion (e.g., run) and psychological verbs (e.g., admire) in both languages. In the word relatedness task, participants judged how closely related pairs of verbs from both categories were. In a speeded semantic categorization task, participants classified the verbs according to their semantic category (psychological or motion). In an arbitrary classification task, participants had to learn how verbs had been assigned to two arbitrary categories. Participants performed better in L1 in the semantic classification task but paradoxically better in L2 in the arbitrary classification task. To account for these effects, the authors used the ratings from the word relatedness task to plot three-dimensional "semantic fields" for the verbs. Cross-language field differences were found to be significantly related to the paradoxical performance and to fluency levels. The results have implications for understanding of how bilinguals represent verbs in the mental lexicon.     

True and false memory in the absence of perceptual identification

Two experiments are reported in which, after attempting to identify a briefly flashed, masked test word, participants were asked to rate the likelihood that it had been presented in an earlier study list. Even when people were unable to identify such items, they demonstrated an ability to discriminate between those that were studied and those that were not studied; ratings given to studied items were significantly higher than ratings given to nonstudied items. This effect does not appear to be a data‐driven phenomenon. In Experiment 1 it was found when the presentation modality was changed from study to test. In Experiment 2 false memory for unidentified items that were related to studied items was shown.     

True and false memory in the absence of perceptual identification

Two experiments are reported in which, after attempting to identify a briefly flashed, masked test word, participants were asked to rate the likelihood that it had been presented in an earlier study list. Even when people were unable to identify such items, they demonstrated an ability to discriminate between those that were studied and those that were not studied; ratings given to studied items were significantly higher than ratings given to nonstudied items. This effect does not appear to be a data-driven phenomenon. In Experiment 1 it was found when the presentation modality was changed from study to test. In Experiment 2 false memory for unidentified items that were related to studied items was shown.     

Dissociated developmental trajectories for semantic and phonological false memories

False recognition following presentation of semantically related and phonologically related word lists was evaluated in 8-, 11-, and 13-year-olds. Children heard lists of words that were either semantic (e.g., bed, rest, wake …) or phonological associates (e.g., pole, bowl, hole …) of a critical unpresented word (e.g., sleep, roll), respectively. A semantic false memory was defined as false recognition of a semantically related but unpresented word. A phonological false memory was defined as false recognition of a phonologically related but unpresented word. False memories in the two tasks showed opposite developmental trends, increasing with age for semantic relatedness and decreasing with age for phonological relatedness.     

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.     

How do associative and phonemic overlap interact to boost illusory recollection?

This project investigated the underlying mechanisms that boost false remember responses when participants receive study words that are both semantically and phonologically similar to a critical lure. Participants completed a memory task in which they were presented with a list of words all associated with a critical lure. Included within the list of semantic associates was a target that was either semantically associated (e.g., yawn) to the critical lure (e.g., sleep) or shared the initial (e.g., slam) or final (e.g., beep) phoneme(s) with the critical lure. After hearing the list, participants recalled each list item and indicated whether they just knew it was on the list or if they instead recollected specific contextual details of that item’s presentation. We found that inserting an initial phonemic overlap target boosted experiences of recollection, but only when semantically related associates were presented beforehand. The results are consistent with models of spoken word recognition and show that established semantic context plus initial phonemic overlap play important roles in boosting false recollection.     

Physical and conceptual priming effects on picture and word identification

In the study phase of these experiments, subjects were asked to think of an item suggested by the omission in an incomplete sentence, and then look at a picture or word describing an item and say whether it was the same as theirs. In the test phase, they were asked to identify studied and nonstudied items presented briefly in either picture or word form. Subjects were then required to recall the words or pictures shown in the study phase. Experiment 1, with a within-subjects design, revealed that the studied pictures were identified more readily than studied words and nonstudied pictures. This indicates a physical priming effect. In word identification, studied words were identified more readily than nonstudied words; however, there was no difference between studied words and studied pictures, and the performance for studied pictures and nonstudied items were largely the same. The physical priming effect on picture identification was also shown in Experiment 2, with a between-subjects design. Different processing mechanisms in picture and word identification are discussed.     

Are nonconscious processes sufficient to produce false memories?

Seamon, Luo, and Gallo (1998) reported evidence that nonconscious processes could produce false recognition in a converging-associates task, whereby subjects falsely remember a nonstudied lure (e.g., sleep) after studying a list of related words (bed, rest, awake...). Zeelenberg, Plomp, and Raaijmakers (2003) failed to observe this false recognition effect when list word recognition was at chance. We critically evaluate the evidence for nonsconscious processing and report the results of a new experiment designed to overcome previous methodological limitations. Consistent with Seamon et al., we found that conscious activation of a related lure during study was not necessary for its subsequent recognition; consistent with Zeelenberg et al., we found no evidence for recognition of related lures under conditions where there was no memory for studied words. It is currently unknown whether conscious recollection of the studied items is necessary for false recognition or if nonconscious activation of the lure is sufficient.     

Eliciting false memories on implicit and explicit memory tests after incidental learning

Abstract: In a false memory experiment, lists of semantic associates (e.g., newspaper, letter, book, etc.) were presented to three groups of participants to induce false memories for critical nonpresented (CN) words (e.g., read) in an incidental learning task. The control group simply estimated the frequency rate in everyday Japanese discourse of each word on a list. The imagery instruction group received an additional instruction to imagine a thematically related converging word from the target words on a list. Participants in the imagery plus writing group received the same instructions as those in the imagery instruction group, but were also required to write down the word they imagined for each list. The results from the implicit and explicit memory tests given after the incidental learning episode showed that the level of priming for CN words was equivalent to that for actually presented target words for all three groups on the implicit test, whereas explicit memory results showed that participants explicitly recognized more target words than CN words. The implications for implicit associative response and fuzzy‐trace theories of false memory, as well as implicit priming, are discussed.     

True and false memory for colour names versus actual colours: Support for the visual distinctiveness heuristic in memory for colour information

In a colour variation of the Deese–Roediger–McDermott (DRM) false memory paradigm, participants studied lists of words critically related to a nonstudied colour name (e.g., “blood, cherry, scarlet, rouge … ”); they later showed false memory for the critical colour name (e.g., “red”). Two additional experiments suggest that participants generate colour imagery in response to such colour-related DRM lists. First, participants claim to experience colour imagery more often following colour-related than standard non-colour-related DRM lists; they also rate their colour imagery as more vivid following colour-related lists. Second, participants exhibit facilitative priming for critical colours in a dot selection task that follows words in the colour-related DRM list, suggesting that colour-related DRM lists prime participants for the actual critical colours themselves. Despite these findings, false memory for critical colour names does not extend to the actual colours themselves (font colours). Rather than leading to source confusion about which colours were self-generated and which were studied, presenting the study lists in varied font colours actually worked to reduce false memory overall. Results are interpreted within the framework of the visual distinctiveness hypothesis.     

On the nature of associative information in recognition memory

In a typical associative-recognition task, participants must distinguish between intact word pairs (both words previously studied together) and rearranged word pairs (both words previously studied but as part of different pairs). The familiarity of the individual items on this task is uninformative because all of the items were seen before, so the only way to solve the task is to rely on associative information. Prior research suggests that associative information is recall-like in nature and may therefore be an all-or-none variable. The present research reports several experiments in which some pairs were strengthened during list presentation. The resulting hit rates and false alarm rates, and an analysis of the corresponding receiver operating characteristic plots, suggest that participants rely heavily on item information when making an associative-recognition decision (to no avail) and that associative information may be best thought of as a some-or-none variable.     

The ironic effect of guessing: increased false memory for mediated lists in younger and older adults

Younger and older adults studied lists of words directly (e.g., creek, water) or indirectly (e.g., beaver, faucet) related to a nonpresented critical lure (CL; e.g., river). Indirect (i.e., mediated) lists presented items that were only related to CLs through nonpresented mediators (i.e., directly related items). Following study, participants completed a condition-specific task, math, a recall test with or without a warning about the CL, or tried to guess the CL. On a final recognition test, warnings (vs. math and recall without warning) decreased false recognition for direct lists, and guessing increased mediated false recognition (an ironic effect of guessing) in both age groups. The observed age-invariance of the ironic effect of guessing suggests that processes involved in mediated false memory are preserved in aging and confirms the effect is largely due to activation in semantic networks during encoding and to the strengthening of these networks during the interpolated tasks.