False memories and the DRM paradigm: effects of imagery, list, and test type

The influence of working memory mechanisms on false memories in immediate and delayed tests

There is growing evidence that false memories can occur in working memory (WM) tasks with only a few semantically related words and seconds between study and test. Abadie and Camos (2019) proposed a new model to explain the formation of false memories by describing the role of articulatory rehearsal and attentional refreshing, the two main mechanisms for actively maintaining information in WM. However, this model has only been tested in recognition tasks. In the present study, we report four experiments testing the model in recall tasks in which the active maintenance of information in WM plays a more important role for retrieval. Short lists of semantically related items were held for a short retention interval filled with a concurrent task that either impaired or not the use of each of the WM maintenance mechanisms. Participants were asked to recall the items immediately after the concurrent task (immediate test) or later, at the end of a block of several trials (delayed test). In the immediate test, semantic errors were more frequent when WM maintenance was impaired. Specifically, rehearsal prevented the occurrence of semantic errors in the immediate test, while refreshing had no effect on their occurrence in this test, but increased semantic errors produced only in the delayed test. These results support Abadie and Camos (2019) model and go further by demonstrating the role of active information maintenance in WM in the emergence of false memories. The implications of these findings for understanding WM-LTM relationships are discussed.

Investigating the neural basis of schematic false memories by examining schematic and lure pattern similarity

ABSTRACTSchemas allow us to make assumptions about the world based upon previous experiences and aid in memory organisation and retrieval. However, a reliance on schemas may also result in increased false memories to schematically related lures. Prior neuroimaging work has linked schematic processing in memory tasks to activity in prefrontal, visual, and temporal regions. Yet, it is unclear what type of processing in these regions underlies memory errors. The current study examined where schematic lures exhibit greater neural similarity to schematic targets, leading to this memory error, as compared to neural overlap with non-schematic lures, which, like schematic lures, are novel items at retrieval. Results showed that patterns of neural activity in ventromedial prefrontal cortex, medial frontal gyrus, middle temporal gyrus, hippocampus, and occipital cortices exhibited greater neural pattern similarity for schematic targets and schematic lures than between schematic lures and non-schematic lures. As such, results suggest that schematic membership, and not object history, may be more critical to the neural processes underlying memory retrieval in the context of a strong schema.

Does context matter for memory? Testing the effectiveness of learning by imagining situated interactions with objects

Mounting evidence supports the efficacy of mental imagery for verbal information retention. Motor imagery, imagining oneself interacting physically with the object to be learned, emerges as an optimal form compared to less physically engaging imagery. Yet, when engaging in mental imagery, it occurs within a specific context that may affect imagined actions and consequently impact the mnemonic benefits of mental imagery. In a first study, participants were given instructions for incidental learning: mental rehearsal, visual imagery, motor imagery or situated motor imagery. The latter, which involved imagining physical interaction with an item within a coherent situation, produced the highest proportion of correct recalls. This highlights memory's role in supporting situated actions and offers the possibility for further developing the mnemonic potential of embodied mental imagery. Furthermore, item-level analysis showed that individuals who engaged in situated motor imagery remembered words primarily due to the sensorimotor characteristics of the words' referent. A second study investigating the role of inter-item distinctiveness in this effect failed to determine the extent to which the situational and motor elements need to be distinctive in order to be considered useful retrieval cues and produce an optimal memory performance.

Investigating the neural basis of schematic false memories by examining schematic and lure pattern similarity

Schemas allow us to make assumptions about the world based upon previous experiences and aid in memory organization and retrieval. However, a reliance on schemas may also result in increased false memories to schematically related lures. Prior neuroimaging work has linked schematic processing in memory tasks to activity in prefrontal, visual, and temporal regions. Yet, it is unclear what type of processing in these regions underlies memory errors. The current study examined where schematic lures exhibit greater neural similarity to schematic targets, leading to this memory error, as compared to neural overlap with non-schematic lures, which, like schematic lures, are novel items at retrieval. Results showed that patterns of neural activity in ventromedial prefrontal cortex, medial frontal gyrus, middle temporal gyrus, hippocampus, and occipital cortices exhibited greater neural pattern similarity for schematic targets and schematic lures than between schematic lures and non-schematic lures. As such, results suggest that schematic membership, and not object history, may be more critical to the neural processes underlying memory retrieval in the context of a strong schema.

The cost of changing language context: The language-dependent recall of fictional stories

Language-dependent recall refers to the language-specific retrieval of memories in which the retrieval success depends on the match between the languages of encoding and retrieval. The present study investigated language-dependent recall in terms of memory accuracy, false memory, and episodic memory characteristics in the free recall of fictional stories. We also asked how language-dependent memories were influenced by language proficiency and visual imagery. One hundred and thirty-seven native Turkish (L1) speakers who were second-language learners of English (L2) were divided into four groups in which they read fictional stories and then recalled them: (1) Turkish reading-Turkish recall, (2) English reading-English recall, (3) English reading-Turkish recall, (4) Turkish reading-English recall. Regardless of the match between L1 or L2, accuracy was higher when participants read and recalled the stories in the same language than when they did it in different languages, showing the language-dependent recall effect. Notably, the effect of match or mismatch between encoding and retrieval languages on accuracy did not depend on L2 proficiency and visual imagery. In addition, false memories were salient, particularly for participants who read the stories in L2 but retrieved them in L1. Overall, our findings suggest that accuracy-oriented memory research provides a comprehensive investigation of language-dependent recall, addressing the links of language-dependent memories with accuracy, false memory, and episodic memory characteristics.

Motor imagery and engagement favour spatial reasoning

Based on the assumption that spatial reasoning relies on the construction of mental models of the states of affairs described in the premises, and on evidence that sensory-motor imagery can enhance cognitive abilities, we hypothesised that imagining moving the objects mentioned in the premises to the specific spatial locations should favour spatial reasoning. The results of Experiment 1 confirmed the prediction: when participants imagined moving the objects mentioned in the premises (dynamic-engagement condition), they drew accurate inferences faster compared with participants who merely read the premises (static-non-engagement condition). Experiment 2 was in part a replication of Experiment 1 but included two additional experimental conditions to control for possible effects of self-engagement in reasoning: in one condition, participants imagined that someone else was moving the objects (dynamic-non-engagement condition), and in the other condition, participants imagined that they were observing the objects (static-engagement condition). The results revealed an interaction between motor imagery and engagement in decreasing response times to spatial problems. We discuss the practical implications of the current results.

Distinctive Sans Forgetica font does not benefit memory accuracy in the DRM paradigm

A common method used by memory scholars to enhance retention is to make materials more challenging to learn-a benefit termed desirable difficulties. Recently, researchers have investigated the efficacy of Sans Forgetica, a perceptually disfluent/distinctive font which may increase processing effort required at study and enhance memory as a result. We examined the effects of Sans Forgetica relative to a standard control font (Arial) on both correct memory and associative memory errors using the Deese/Roediger-McDermott (DRM) false memory paradigm, to evaluate Sans Forgetica effects on overall memory accuracy. Across four experiments, which included nearly 300 participants, Sans Forgetica was found to have no impact on correct or false memory of DRM lists relative to a standard Arial control font, regardless of whether font type was manipulated within or between subjects or whether memory was assessed via free recall or recognition testing. Our results indicate that Sans Forgetica is ineffective for improving memory accuracy even when accounting for associative memory errors.

Item-specific encoding reduces false recognition of homograph and implicit mediated critical lures

We evaluated the effects of item-specific and relational encoding instructions on false recognition for critical lures that originated from homograph and mediated study lists. Homograph lists contained list items that were taken from two meanings of the same critical lure (e.g., autumn, trip, harvest, stumble; for fall) which disrupted thematic/gist consistency of the list. Mediated lists contained unrelated list items (e.g., slippery, spicy, vent, sleigh) that were indirectly related to a critical lure (e.g., cold), through a set of non-presented mediators (e.g., wet, hot, air, snow), and had no thematic/gist consistency. In two experiments, item-specific and relational encoding improved correct recognition relative to a read-only control task, but only item-specific encoding reduced false recognition of critical lures. Signal-detection analyses indicated that the item-specific reduction increased test-based monitoring. The item-specific reduction for homograph and mediated critical lures is consistent with the activation-monitoring framework given gist-based processes are reduced or eliminated on these list types.

Self-imagery and advertising effectiveness: the role of sense of presence

The purpose of this study was to assess whether self-imagery is more effective than other-imagery, and if so, to investigate the mechanism of how self-imagery generates more increased positive responses from consumers. Furthermore, we explored the boundary conditions associated with reduced positive effects of self-imagery on consumer responses. The results of Experiment 1 suggest that self-imagery was more effective than other-imagery in generating a favorable attitude toward an advertisement and purchase intention, since it enhanced a sense of presence, and consequently, imagery engagement. However, based on the results of Experiment 2, when an advertisement evoked a sense of high-risk, self-imagery generated a less favorable attitude toward the advertisement than other-imagery due to the emotion of fear evoked by the advertisement.

Imagination Reduces False Memories for Everyday Action Sentences: Evidence From Pragmatic Inferences

Human memory can be unreliable, and when reading a sentence with a pragmatic implication, such as "the karate champion hit the cinder block," people often falsely remember that the karate champion "broke" the cinder block. Yet, research has shown that encoding instructions affect the false memories we form. On the one hand, instructing participants to imagine themselves manipulating the to-be-recalled items increase false memories (imagination inflation effect). But on the other hand, instructions to imagine have reduced false memories in the DRM paradigm (imagination facilitation effect). Here, we explored the effect of imaginal encoding with pragmatic inferences, a way to study false memories for information about everyday actions. Across two experiments, we manipulated imaginal encoding through the instructions given to participants and the after-item filler task (none vs. math operations). In Experiment 1, participants were either assigned to the encoding condition of imagine+no filler; pay attention+math; or memorize+math. In Experiment 2, the encoding instructions (imagine vs. memorize) and the filler task (none vs. math) were compared across four separate conditions. Results from the two experiments showed that imagination instructions lead to better memory, by showing a higher proportion of correct responses and better performance in a memory benefit index. Similarly, a significant reduction of false memories was observed across both experiments, even though a complementary Bayesian analysis only supported this conclusion for Experiment 1. The findings show that imaginal encoding improves memory, suggesting the engagement of a distinctiveness heuristic and source-monitoring process.

Manipulations of List Type in the DRM Paradigm: A Review of How Structural and Conceptual Similarity Affect False Memory

The use of list-learning paradigms to explore false memory has revealed several critical findings about the contributions of similarity and relatedness in memory phenomena more broadly. Characterizing the nature of "similarity and relatedness" can inform researchers about factors contributing to memory distortions and about the underlying associative and semantic networks that support veridical memory. Similarity can be defined in terms of semantic properties (e.g., shared conceptual and taxonomic features), lexical/associative properties (e.g., shared connections in associative networks), or structural properties (e.g., shared orthographic or phonological features). By manipulating the type of list and its relationship to a non-studied critical item, we review the effects of these types of similarity on veridical and false memory. All forms of similarity reviewed here result in reliable error rates and the effects on veridical memory are variable. The results across a variety of paradigms and tests provide partial support for a number of theoretical explanations of false memory phenomena, but none of the theories readily account for all results.

Reducing False Recognition in the Deese-Roediger/McDermott Paradigm: Related Lures Reveal How Distinctive Encoding Improves Encoding and Monitoring Processes

In the Deese-Roediger/McDermott (DRM) paradigm, distinctive encoding of list items typically reduces false recognition of critical lures relative to a read-only control. This reduction can be due to enhanced item-specific processing, reduced relational processing, and/or increased test-based monitoring. However, it is unclear whether distinctive encoding reduces false recognition in a selective or global manner. To examine this question, participants studied DRM lists using a distinctive item-specific anagram generation task and then completed a recognition test which included both DRM critical lures and either strongly related lures (Experiment 1) or weakly related lures (Experiment 2). Compared to a read-control group, the generate groups showed increased correct recognition and decreased false recognition of all lure types. We then estimated the separate contributions of encoding and retrieval processes using signal-detection indices. Generation improved correct recognition by both increasing encoding of memory information for list words and by increasing memory monitoring at test. Generation reduced false recognition by reducing the encoding of memory information and by increasing memory monitoring at test. The reduction in false recognition was equivalent for critical lures and related lures, indicating that generation globally reduces the encoding of related non-presented items at study (not just critical lures), while globally increasing list-theme-based monitoring at test.

Multiple species of distinctiveness in memory? Comparing encoding versus statistical distinctiveness on recognition

The distinctiveness effect refers to the memorial benefit of processing unique or item-specific features of a memory set relative to a non-distinctive control. Traditional distinctiveness effects are accounted for based on qualitative differences in how distinctive items are encoded and subsequently retrieved. This study evaluates whether a separate species of distinctiveness - statistical distinctiveness - may provide an additional benefit to memory beyond traditional task-based processes. Statistical distinctiveness refers to the relative frequency with which a specific memory item or set is processed. The current study examined the presence of statistical distinctiveness through a series of levels-of-processing mixed groups in which related lists were studied using two of the following three tasks to promote either shallow ("E" identification), neutral (reading silently), or deep/distinctive (pleasantness ratings) processing followed by a recognition test. Participants studied lists in which these tasks were used frequently (80% of lists), equally (50% of lists), or infrequently (20% of lists). No recognition advantage was found when tasks were completed infrequently versus frequently. Instead, recognition was greatest for the deeper/more distinctive task - a pattern consistent with an encoding but not a statistical distinctiveness account.

Improved inference in mediation analysis: Introducing the model-based constrained optimization procedure

Mediation analysis is an important approach for investigating causal pathways. One approach used in mediation analysis is the test of an indirect effect, which seeks to measure how the effect of an independent variable impacts an outcome variable through 1 or more mediators. However, in many situations the proposed tests of indirect effects, including popular confidence interval-based methods, tend to produce poor Type I error rates when mediation does not occur and, more generally, only allow dichotomous decisions of "not significant" or "significant" with regards to the statistical conclusion. To remedy these issues, we propose a new method, a likelihood ratio test (LRT), that uses nonlinear constraints in what we term the model-based constrained optimization (MBCO) procedure. The MBCO procedure (a) offers a more robust Type I error rate than existing methods; (b) provides a p value, which serves as a continuous measure of compatibility of data with the hypothesized null model (not just a dichotomous reject or fail-to-reject decision rule); (c) allows simple and complex hypotheses about mediation (i.e., 1 or more mediators; different mediational pathways); and (d) allows the mediation model to use observed or latent variables. The MBCO procedure is based on a structural equation modeling framework (even if latent variables are not specified) with specialized fitting routines, namely with the use of nonlinear constraints. We advocate using the MBCO procedure to test hypotheses about an indirect effect in addition to reporting a confidence interval to capture uncertainty about the indirect effect because this combination transcends existing methods. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Is it all in the details? Description content and false recognition errors

In three experiments, we examined the effect of embellished content on memory errors for thematically related items as well as whether an encoding manipulation, specifically instructions to visualize content, further affects those errors. Using a modified Deese-Roediger-McDermott (DRM) paradigm, participants listened to subsets of DRM items embedded within scene descriptions. Some descriptions embellished item connections, weaving them into cohesive scenes. Other descriptions only made general reference to scenes, mentioning the items in list-like format. Listening to more detailed descriptions, compared to general scene references, elicited higher false recognition errors (Experiments 1 and 3). However, when description details varied within the same encoding series, as expected, false recognition errors did not differ significantly (Experiments 2 and 3). Results further suggest that more detailed content was more vividly imagined, providing one possible mechanism for increases in false recognition (Experiment 3). Implications for theoretical discussions of encoding task effects on false recognition errors are discussed.

Distinctive encoding of a subset of DRM lists yields not only benefits, but also costs and spillovers

Prior research has emphasized that performing distinctive encoding on a subset of lists in the DRM paradigm suppresses false recognition; we show that its benefits can be mitigated by costs and spillover effects. Within groups read half the DRM lists and solved anagrams for the other half using a strategy that emphasized either item-specific or relational processing. Their recognition was compared to three pure-list control groups (read, item-specific generation, relational generation). Correct recognition in the within groups showed a benefit for generate items and a cost for read items, resulting in little net improvement relative to pure reading. False recognition in the within groups was reduced following item-specific vs. relational generation, but there was again little net improvement. Most surprisingly, false recognition in the within groups was greater for generate than read lists. This pattern suggests that relational processing of read lists spilled over to generate lists, boosting false recognition for generate lists. Distinctive encoding of a subset of items does not appear to globally improve memory accuracy.

Item-specific processing reduces false recognition in older and younger adults: Separating encoding and retrieval using signal detection and the diffusion model

Our study examined processing effects in improving memory accuracy in older and younger adults. Specifically, we evaluated the effectiveness of item-specific and relational processing instructions relative to a read-only control task on correct and false recognition in younger and older adults using a categorized-list paradigm. In both age groups, item-specific and relational processing improved correct recognition versus a read-only control task, and item-specific encoding decreased false recognition relative to both the relational and read-only groups. This pattern was found in older adults despite overall elevated rates of false recognition. We then applied signal-detection and diffusion-modeling analyses, which separately utilized recognition responses and the latencies to those responses to estimate contributions of encoding and monitoring processes on recognition decisions. Converging evidence from both analyses demonstrated that item-specific processing benefits to memory accuracy were due to improvements of both encoding (estimates of d' and drift rate) and monitoring (estimates of lambda and boundary separation) processes, and, importantly, occurred similarly in both younger and older adults. Thus, older and younger adults showed similar encoding-based and test-based benefits of item-specific processing to enhance memory accuracy.

Item-specific and relational processing both improve recall accuracy in the DRM paradigm

Using the Deese-Roediger-McDermott (DRM) paradigm, Huff and Bodner found that both item-specific and relational variants of a task improved correct recognition, but only the item-specific variants reduced false recognition, relative to a read-control condition. Here, we examined the outcome pattern when memory was tested using free recall, using the same item-specific versus relational task variants across three experiments as our previous study (processing instructions, pleasantness ratings, anagram generation). The outcome pattern in recall was similar to recognition, except relational processing at study actually reduced the DRM illusion, though not as much as item-specific processing. To reconcile this task difference, we suggest that the memory information laid down during relational encoding enhances the familiarity of the critical items at test. To the extent that familiarity is used less as a basis for responding in free recall than in recognition, relational processing ironically reduces rather than increases the DRM illusion in recall.

Animacy effects in episodic memory: do imagery processes really play a role?

Animates are remembered better than inanimates because the former are ultimately more important for fitness than the latter. What, however, are the proximate mechanisms underpinning this effect? We focused on imagery processes as one proximate explanation. We tested whether animacy effects are related to the vividness of mental images (Study 1), or to the dynamic/motoric nature of mental images corresponding to animate words (Study 2). The findings showed that: (1) Animates are not estimated to be more vivid than inanimates; (2) The potentially more dynamic nature of the representations of animates does not seem to be a factor making animates more memorable than inanimates. We compared (Study 3) a condition in which participants had to categorise animate and inanimate words with a condition in which they had to form mental images from them. The animacy effect was significant after categorising but not after forming mental imagery. In Study 4, we compared the recall rates of animates and inanimates after these words had been encoded with or without a concurrent visual-spatial memory load. Again, animates were better remembered than inanimates. Taken overall, the findings do not fit well with the hypothesis that imagery processes support animacy effects in memory.