Unrelated Lures Research Articles

False memory-guided eye movements: insights from a DRM-Saccade paradigm

ABSTRACT The Deese-Roediger and McDermott (DRM) paradigm and visually guided saccade tasks are both prominent research tools in their own right. This study introduces a novel DRM-Saccade paradigm, merging both methodologies. We used rule-based saccadic eye movements whereby participants were presented with items at test and were asked to make a saccade to the left or right of the item to denote a recognition or non-recognition decision. We measured old/new recognition decisions and saccadic latencies. Experiment 1 used a pro/anti saccade task to a single target. We found slower saccadic latencies for correct rejection of critical lures, but no latency difference between correct recognition of studied items and false recognition of critical lures. Experiment 2 used a two-target saccade task and also measured corrective saccades. Findings corroborated those from Experiment 1. Participants adjusted their initial decisions to increase accurate recognition of studied items and rejection of unrelated lures but there were no such corrections for critical lures. We argue that rapid saccades indicate cognitive processing driven by familiarity thresholds. These occur before slower source-monitoring is able to process any conflict. The DRM-Saccade task could effectively track real-time cognitive resource use during recognition decisions.

Consequences of curiosity for recognition memory in younger and older adults.

Older adults are more prone to false recognition than younger adults, particularly when new information is semantically related to old information. Curiosity, which guides information-seeking behavior and has beneficial effects on memory across the life span, may offer protection against false recognition, but this hypothesis has not been tested experimentally to date. The current study investigated the effect of curiosity on correct and false recognition in younger and older adults (total N = 102) using a trivia paradigm. On Day 1 of the study, participants encoded trivia questions and answers while rating their curiosity levels. On Day 2, participants completed a surprise old/new recognition test in which they saw the same trivia questions. Half of the questions were paired with old (correct) answers, and half were paired with new (incorrect) answers. New answers were either semantically related or unrelated to correct answers. For both age groups, curiosity at encoding was positively associated with correct recognition. For older adults, semantically related lures produced more false recognition than unrelated lures. However, this effect was mitigated by curiosity, such that older adults were less likely to endorse semantically related lures for high- versus low-curiosity questions. Overall, these results extend prior findings of curiosity-related memory benefits to the domain of recognition memory, and they provide novel evidence that curiosity may protect against false memory formation in older adults.

Individuals with low arithmetic abilities are sensitive to interference during knowledge retrieval from long-term memory across different domains

ABSTRACT Individuals show large individual differences in arithmetic abilities, especially in arithmetic facts. However, it is still unclear if individual differences in these abilities can be explained through individual differences in sensitivity to interference during retrieval from the associative network, and whether this sensitivity to interference is domain-general. To this end, we compared 18 adults with low arithmetic abilities with 18 intelligence matched individuals with high arithmetic abilities in two arithmetic and one lexico-semantic task. While individuals with low arithmetic abilities performed worse (longer response time and lower accuracy) on related lures, where interference occurs, individuals with high arithmetic abilities performed equally well on related and unrelated lures. This pattern of results emerged in the arithmetic tasks as well as in the lexico-semantic task. This finding indicates that sensitivity to interference is a domain-general construct hindering the selective retrieval of information from long-term memory in individuals with low arithmetic abilities.

Production can enhance semantic encoding: Evidence from forced-choice recognition with homophone versus synonym lures.

The production effect-better memory for words read aloud rather than silently-has been attributed to responses at test being guided by memory for the act of production. In Experiment 1, we evaluated this distinctiveness account by comparing production effects in forced-choice recognition when lures were either homophones of the targets (toad or towed?) or unrelated words (toad or seam?). If the production effect at test was driven solely by memory for the productive act (e.g., articulation, auditory processing), then the effect should be reduced with homophone lures. Contrary to that prediction, the production effect did not differ credibly between homophone-lure and unrelated-lure groups. Experiment 1 led us to hypothesize that production may also boost semantic encoding, and that participants use memory of semantic encoding to guide their forced-choice responses. Consistent with these hypotheses, using synonym lures to interfere with semantic-based decisions (poison or venom?) reduced the production effect relative to using unrelated lures (poison or ethics?) in Experiment 2. Our findings suggest that enhanced conceptual encoding may be another useful product of production.

Positive Schizotypy Increases the Acceptance of Unpresented Materials in False Memory Tasks in Non-clinical Individuals.

Enhanced spreading of semantic activation has been hypothesized to underlie some of the most significant symptoms of schizotypal personality, like thought disorder, odd speech, delusion, or magical thinking. We applied the Deese/Roediger-McDermott false memory task to the study of semantic activation in a group of 123 non-clinical individuals varying in the three dimensions of schizotypal personality: positive, negative and disorganized schizotypy. In the study phase, we presented them with lists composed of words semantically associated to unpresented critical words. Then, they responded to a recognition questionnaire including previously presented words and critical unpresented lures, as well as weakly related and unrelated unpresented lures. Participants rated their confidence in recognizing each word. They also filled in a standardized schizotypal personality questionnaire. Confirming the false memory effect, recognition ratings provided in response to critical words were higher than those produced for both weakly related and unrelated items. Crucially, scores in the positive dimension increased recognition percentages and confidence ratings for weakly related and unrelated lures. This study indicates that high levels of positive schizotypy might influence the tendency to accept false memories of unrelated unpresented material.

Probability of target recollection varies with target-lure relatedness under the dual process signal detection model

The ROC function plots hit and false alarm rates against one another. For item recognition the z-transformed ROC (Z-ROC) function is typically linear with slope less than one. The Dual Process Signal Detection (DPSD) and Unequal Variance Signal Detection (UVSD) models see the slope as reflecting the ratio of the lure and target evidence standard deviations. The DPSD model in addition sees the slope as co-varying with estimates of target recollection probability (R). This follows because the slope decreases with increases in the target evidence standard deviation which in turn increases with increases in the numbers of high evidence recollection items. However our results suggest that the lure evidence standard deviation, and thus the Z-ROC slope, can vary with factors seemingly unrelated to target recollection, posing problems for DPSD estimates of R. In word recognition the standard deviation of lure confidence ratings and the slope of the z-ROC function were larger with semantically related than unrelated lures. When the data for related and unrelated lures were fit separately, the standard two-parameter DPSD model, implausibly, set R lower for related than unrelated lures. The UVSD model, more plausibly, set the lure evidence standard deviation larger for related than unrelated lures.

It's about time: Adding processing to neuroemergentism

Alzheimer's disease (AD) patients are known to present semantic memory impairments, and semantic processing plays a crucial role in the formation of false memories. We assessed 40 early stage AD patients and 35 matched healthy volunteers with an emotional version of the Deese-Roediger-McDermott paradigm, which allows the study of false memory formation. Participants were presented with three negative, three neutral and three positive lists of words, each semantically associated to a critical unpresented word. After the presentation of the lists the volunteers were asked to respond to a recognition questionnaire stating whether these critical lures, as well as other presented and unpresented words, had been previously shown or not. We replicate the pattern of decreased discriminability between list-related and -unrelated items for AD patients compared to healthy seniors observed in previous studies. Moreover, like control participants, AD patients displayed enhanced true recognition for emotional materials, both positive and negative. With regards to false recognition, our data show decreased discriminability between related and unrelated lures for positive material. These results point out differential involvement of semantic-based information during memory formation in AD patients compared to healthy seniors. Nevertheless, our data indicate that emotional content effects over semantic-based false memory formation persist in this population, at least at early stages of disease development.

Differential effects of negative and positive emotional content over veridical and false recognition in aging and Alzheimer's disease

Abstract Alzheimer's disease (AD) patients are known to present semantic memory impairments, and semantic processing plays a crucial role in the formation of false memories. We assessed 40 early stage AD patients and 35 matched healthy volunteers with an emotional version of the Deese-Roediger-McDermott paradigm, which allows the study of false memory formation. Participants were presented with three negative, three neutral and three positive lists of words, each semantically associated to a critical unpresented word. After the presentation of the lists the volunteers were asked to respond to a recognition questionnaire stating whether these critical lures, as well as other presented and unpresented words, had been previously shown or not. We replicate the pattern of decreased discriminability between list-related and -unrelated items for AD patients compared to healthy seniors observed in previous studies. Moreover, like control participants, AD patients displayed enhanced true recognition for emotional materials, both positive and negative. With regards to false recognition, our data show decreased discriminability between related and unrelated lures for positive material. These results point out differential involvement of semantic-based information during memory formation in AD patients compared to healthy seniors. Nevertheless, our data indicate that emotional content effects over semantic-based false memory formation persist in this population, at least at early stages of disease development.

Positive and negative effects of gender expertise on episodic memory.

In two experiments, we examined the role of differential levels of knowledge between the genders in different domains, which we term gender expertise, in accounting for differences in episodic memory performance. In Experiment 1, we validated the assumption of differential gender expertise among men and women and selected the categories for the subsequent experiments. In Experiment 2, participants from both genders studied exemplars from these female-oriented, male-oriented, and gender-neutral categories and were tested after 24 hours on studied items, critical lures, and unrelated lures. A gender-congruity effect was found in terms of the recognition rates of both studied items and critical lures: Participants from each gender recognized more studied items and more critical lures from gender-congruent categories than from gender-incongruent categories. A parallel pattern of results was found for subjective confidence, supporting the notion that gender congruity enhanced the phenomenological experience that an item was studied. Our findings highlight the unique role of gender expertise in accounting for gender-congruity effects in episodic memory performance, using a well-defined operationalization of gender expertise. These findings show that in addition to benefits in terms of enhancing true memory, gender expertise also has a "dark side" of increasing false memories.

Effects of perceptual similarity but not semantic association on false recognition in aging.

This study investigated semantic and perceptual influences on false recognition in older and young adults in a variant on the Deese-Roediger-McDermott paradigm. In two experiments, participants encoded intermixed sets of semantically associated words, and sets of unrelated words. Each set was presented in a shared distinctive font. Older adults were no more likely to falsely recognize semantically associated lure words compared to unrelated lures also presented in studied fonts. However, they showed an increase in false recognition of lures which were related to studied items only by a shared font. This increased false recognition was associated with recollective experience. The data show that older adults do not always rely more on prior knowledge in episodic memory tasks. They converge with other findings suggesting that older adults may also be more prone to perceptually-driven errors.

Preserved criterion flexibility in item recognition in older adults.

Young and older adults studied a list of words and then took 2 successive tests of item recognition, an easy test consisting of studied words and unrelated lures and a hard test pitting studied words against semantically related lures. When the easy test was first, participants in both age groups adopted a more stringent criterion on the harder test. When the hard test was first, no criterion shift was seen. Older adults can assess the consequences for accuracy of maintaining a lenient criterion when discrimination becomes more difficult and can take appropriate action to control errors under these conditions. (PsycINFO Database Record

The neural correlates of correctly rejecting lures during memory retrieval: the role of item relatedness.

Successful memory retrieval is predicated not only on recognizing old information, but also on correctly rejecting new information (lures) in order to avoid false memories. Correctly rejecting lures is more difficult when they are perceptually or semantically related to information presented at study as compared to when lures are distinct from previously studied information. This behavioral difference suggests that the cognitive and neural basis of correct rejections differs with respect to the relatedness between lures and studied items. The present study sought to identify neural activity that aids in suppressing false memories by examining the network of brain regions underlying correct rejection of related and unrelated lures. Results showed neural overlap in the right hippocampus and anterior parahippocampal gyrus associated with both related and unrelated correct rejections, indicating that some neural regions support correctly rejecting lures regardless of their semantic/perceptual characteristics. Direct comparisons between related and unrelated correct rejections showed that unrelated correct rejections were associated with greater activity in bilateral middle and inferior temporal cortices, regions that have been associated with categorical processing and semantic labels. Related correct rejections showed greater activation in visual and lateral prefrontal cortices, which have been associated with perceptual processing and retrieval monitoring. Thus, while related and unrelated correct rejections show some common neural correlates, related correct rejections are driven by greater perceptual processing whereas unrelated correct rejections show greater reliance on salient categorical cues to support quick and accurate memory decisions.

Misremembering what you see or hear: Dissociable effects of modality on short- and long-term false recognition.

False working memories readily emerge using a visual item-recognition variant of the converging associates task. Two experiments, manipulating study and test modality, extended prior working memory results by demonstrating a reliable false recognition effect (more false alarms to associatively related lures than to unrelated lures) within seconds of encoding in either the visual or auditory modality. However, false memories were nearly twice as frequent when study lists were seen than when they were heard, regardless of test modality, although study-test modality mismatch was generally disadvantageous (consistent with encoding specificity). A final experiment that varied study-test modality using a hybrid short- and long-term memory test (Flegal, Atkins & Reuter-Lorenz, 2010) replicated the auditory advantage in the short term but revealed a reversal in the long term: The false memory effect was greater in the auditory study-test condition than in the visual study-test condition. Thus, the same encoding conditions gave rise to an opposite modality advantage depending on whether recognition was tested under short-term or long-term memory conditions. Although demonstrating continuity in associative processing across delay, the results indicate that delay condition affects the availability of modality-dependent features of the memory trace and, thus, distinctiveness, leading to dissociable patterns of short- and long-term memory performance.

Semantic processes leading to true and false memory formation in schizophrenia

Encoding semantic relationships between items on word lists (semantic processing) enhances true memories, but also increases memory distortions. Episodic memory impairments in schizophrenia (SZ) are strongly driven by failures to process semantic relations, but the exact nature of these relational semantic processing deficits is not well understood. Here, we used a false memory paradigm to investigate the impact of implicit and explicit semantic processing manipulations on episodic memory in SZ. Thirty SZ and 30 demographically matched healthy controls (HC) studied Deese/Roediger–McDermott (DRM) lists of semantically associated words. Half of the lists had strong implicit semantic associations and the remainder had low strength associations. Similarly, half of the lists were presented under “standard” instructions and the other half under explicit “relational processing” instructions. After study, participants performed recall and old/new recognition tests composed of targets, critical lures, and unrelated lures. HC exhibited higher true memories and better discriminability between true and false memory compared to SZ. High, versus low, associative strength increased false memory rates in both groups. However, explicit “relational processing” instructions positively improved true memory rates only in HC. Finally, true and false memory rates were associated with severity of disorganized and negative symptoms in SZ. These results suggest that reduced processing of semantic relationships during encoding in SZ may stem from an inability to implement explicit relational processing strategies rather than a fundamental deficit in the implicit activation and retrieval of word meanings from patients' semantic lexicon.

Both differences in encoding processes and monitoring at retrieval reduce false alarms when distinctive information is studied

A reduction in false alarms to critical lures is observed in the DRM paradigm (Roediger & McDermott, 1995) when distinctive information is presented at encoding. Two mechanisms have been proposed to account for this reduction. According to the monitoring theory (e.g., the distinctiveness heuristic), lack of diagnostic recollection serves as a basis for discarding non-presented lures. According to the encoding theory, presenting distinctive information at study leads to impoverished relational processing, which results in a reduction in memorial information elicited by critical lures. In the present study a condition was created in which the use of the distinctiveness heuristic was precluded by associating, within the same study, lures with distinctive information in a context different from the study session. Under that condition reduction in false alarms to distinctive critical lures was still observed. This result supports the predictions of the encoding theory. However, when in the same study the use of the distinctiveness heuristic was not precluded, reductions in false alarms to unrelated lures were also observed when distinctive information was presented at study, indicating that both mechanisms are likely to contribute to the rejection of false memories.

Neural mechanisms of semantic interference and false recognition in short-term memory

Decades of research using the Deese–Roediger–McDermott (DRM) paradigm have demonstrated that episodic memory is vulnerable to semantic distortion, and neuroimaging investigations of this phenomenon have shown dissociations between the neural mechanisms subserving true and false retrieval from long-term memory. Recently, false short-term memories have also been demonstrated, with false recognition of items related in meaning to memoranda encoded less than 5s earlier. Semantic interference is also evident in short-term memory, such that correct rejection of related lures is slowed relative to correct rejection of unrelated lures. The present research constitutes the first fMRI investigation of false recognition and semantic interference in short-term memory using a short-term DRM paradigm in which participants retained 4 semantic associates over a short 4-s filled retention interval. Results showed increased activation in the left mid-ventrolateral prefrontal cortex (BA45) associated with semantic interference, and significant correlations between these increases and behavioral measures of interference across subjects. Furthermore, increases in dorsolateral PFC occurred when related lures were correctly rejected versus falsely remembered. Compared with false recognition, true recognition was associated with increases in left fusiform gyrus, a finding consistent with the notion that increased perceptual processing may distinguish true from false recognition over both short and long retention intervals. Findings are discussed in relation to current models of interference resolution in short-term memory, and suggest that false short-term recognition occurs as a consequence of the failure of frontally mediated cognitive control processes which adjudicate semantic familiarity in support of accurate mnemonic retrieval.

The inverse list length effect: A challenge for pure exemplar models of recognition memory

When multiple items from a category are presented at study during a recognition memory procedure, false alarms to lures drawn from the same category increase. Distributed exemplar models of recognition assume that these effects occur because the representations of related lures are similar to the representations of studied items thus increasing the global matching strength of these items. We show that if list length is manipulated by keeping the number of categories constant, but increasing the number of exemplars in each category, then the unrelated false alarm rate decreases – thus inducing an inverse list length effect. Furthermore, if category structure is made less obvious by distributing items from a category through the list rather than presenting them in a blocked fashion the effect of length is less pronounced. This pattern suggests that it is subjects’ awareness of the categories on the list that is responsible for both related and unrelated false alarms. Simulations demonstrate that pure exemplar models such as the original version of the Retrieving Effectively from Memory model ( Shiffrin & Steyvers, 1997, REM) are not capable of accounting for the results. Rather a representation of the studied categories that subjects can use to reject unrelated lures must be formed. We show how a version of the Bind Cue Decide Model of Episodic Memory ( Dennis & Humphreys, 2001, BCDMEM) can account for the data using a category representation of this kind.

Discriminating Semantic from Episodic Relatedness in Young and Older Adults

ABSTRACT The ability of young (aged 18–30) and older (aged 60–80) adults to discriminate pre-experimental (semantic) from experimental (episodic) associations was examined. Participants studied a list containing semantically related and unrelated word pairs and then made either associative recognition (Experiments 1a and b) or semantic relatedness (Experiment 2) judgments at various response deadlines. For associative recognition judgments, both young and older adults benefited from semantic relatedness, leading to more hits for related than unrelated pairs, and at the long response deadline, older adults' performance on those pairs matched that of young participants. Also, both young and older adults demonstrated superior discrimination for unrelated lures whose members had originally been studied in related pairs – evidence for recall-to-reject processing in both age groups. In making semantic relatedness judgments, both young and older adults showed an episodic priming effect. When older adults can rely on long-standing associations, their performance resembles that of young adults – both in associative recognition and in episodic priming.

List Strength Effect without List Length Effect in Recognition Memory

The study of list length effects (adding items to a list affects memory for the other items) and list strength effects (strengthening some items in a list affects memory for the nonstrengthened items) is important to constrain models of memory. In recognition memory, a list length effect is generally found, whereas a list strength effect is not. Using the switched-plurality procedure in an old-new recognition task (e.g., study banana; test bananas), we found the opposite pattern. Length manipulations caused no change in memory performance, whereas strength manipulations did. The list strength effect was found when recollection was likely to operate at test (with switched-plurality lures). When recollection was unlikely to operate (with unrelated lures), the strength effect disappeared. The result was observed using both a size judgement task (which has previously produced positive list strength effects) and a pleasantness judgement task (which has not yielded list strength effects before).

Phantom ROC: Recollection rejection in a hybrid conjoint recognition signal detection model

The present experiments test predictions of dual process models with regards to recollection rejection using a model called phantom ROC. Participants studied pictures and then took a recognition test in which they were presented with targets (i.e., the exact picture presented), related lures (i.e., the same object but from a different angle), and unrelated lures (i.e., objects that had not been shown). For each item, participants answered both standard recognition and meaning recognition questions. In Experiment 1 participants studied pictures under either full attention or divided attention. In Experiment 2 some participants were told that no object was shown twice (i.e., mutual exclusivity instructions), while others were told that both camera angles might have been shown for some objects (no mutual exclusivity instructions). The present experiments provide three converging measures, all of which are consistent with dual process models that propose a recollection rejection mechanism.