Item-specific processing reduces false memories

We examined the effect of item-specific and relational encoding instructions on false recognition in two experiments in which the DRM paradigm was used (Deese, 1959; Roediger & McDermott, 1995). Type of encoding (item-specific or relational) was manipulated between subjects in Experiment 1 and within subjects in Experiment 2. Decision-based explanations (e.g., the distinctiveness heuristic) predict reductions in false recognition in between-subjects designs, but not in within-subjects designs, because they are conceptualized as global shifts in decision criteria. Memory-based explanations predict reductions in false recognition in both designs, resulting from enhanced recollection of item-specific details. False recognition was reduced following item-specific encoding instructions in both experiments, favoring a memory-based explanation. These results suggest that providing unique cues for the retrieval of individual studied items results in enhanced discrimination between those studied items and critical lures. Conversely, enhancing the similarity of studied items results in poor discrimination among items within a particular list theme. These results are discussed in terms of the item-specific/ relational framework (Hunt & McDaniel, 1993).     

The effects of repeating a recognition test in lorazepam-induced amnesia: Evidence for impaired contextual memory as a cause of amnesia

In two experiments, a recognition test for an earlier presented list was given twice in immediate succession (Test 1 and Test 2). On the hypothesis that anterograde amnesia for episodic memory involves a deficit in contextual memory, amnesic subjects should confuse familiarity with distractor items gained during Test 1 with familiarity gained during original list presentation. As a result, they should think that they recognize more items on Test 2. This will lower recognition efficiency in Test 2 by increasing false alarms rather than by reducing hits. For subjects with an amnesia induced by lorazepam, but not for control subjects, recognition efficiency was substantially reduced in Test 2 in both experiments. As predicted, this impairment was due to a large increase in false alarms, with no decrease in the number of hits. The impairment could not be explained by a difference in recognition level between lorazepam and control subjects on Test 1. These findings therefore support the contextual memory deficit hypothesis of anterograde amnesia. Their implications for understanding the relationship between recall and recognition in amnesia are discussed.     

Dissociative effects of orthographic distinctiveness in pure and mixed lists: an item-order account

We apply the item-order theory of list composition effects in free recall to the orthographic distinctiveness effect. The item-order account assumes that orthographically distinct items advantage item-specific encoding in both mixed and pure lists, but at the expense of exploiting relational information present in the list. Experiment 1 replicated the typical free recall advantage of orthographically distinct items in mixed lists and the elimination of that advantage in pure lists. Supporting the item-order account, recognition performances indicated that orthographically distinct items received greater item-specific encoding than did orthographically common items in mixed and pure lists (Experiments 1 and 2). Furthermore, order memory (input–output correspondence and sequential contiguity effects) was evident in recall of pure unstructured common lists, but not in recall of unstructured distinct lists (Experiment 1). These combined patterns, although not anticipated by prevailing views, are consistent with an item-order account.     

Influence of motoric encoding on forgetting function of memory for action sentences in patients with Alzheimer's disease

This study assessed whether verbal encoding and motoric encoding have different effects on the forgetting function for action sentences of patients with Alzheimer's disease. Subjects were 13 healthy elderly adults and 10 patients diagnosed with Alzheimer's disease. Three tasks were used: verbal tasks, subject-performed tasks, observed tasks. On the verbal tasks, subjects only heard the action sentences as read to them. On the subject-performed tasks, subjects heard, then performed each action sentence. On the observed tasks, subjects heard the action sentences read while observing the object mentioned in each action sentence. After presentation of each task, subjects conducted immediate and 30-min. delayed recall tests, and then a recognition test. Analysis indicated recall performance for subject-performed tasks was significantly better than that for verbal tasks and observed tasks at both immediate and delayed recall in each group. On the recognition test, carrying out the action had no effect, but for both groups recognition was enhanced by observing the object. Elderly adults performed significantly better than patients on all tasks of recall and recognition. However, the results indicate that patients with Alzheimer's disease can use multimodal resources from motoric encoding even if time passes.     

The effects of mediated word lists on false recall and recognition

False memory effects were explored using unrelated list items (e.g., slope, reindeer, corn) that were related to mediators (e.g., ski, sleigh, flake) that all converged upon a single nonpresented critical item (CI; e.g., snow). In Experiment 1, participants completed either an initial recall test or arithmetic problems after study, followed by a final recognition test. Participants did not falsely recall CIs on the initial test; however, false alarms to CIs did occur in recognition, but only following an initial recall test. In Experiment 2, participants were instructed to guess the CI, followed by a recognition test. The results replicated Experiment 1, with an increase in CI false alarms. Experiment 3 controlled for item effects by replacing unrelated recognition items from Experiment 1 with both CIs and list items from nonpresented lists. Once again, CI false alarms were found when controlling for lexical characteristics, demonstrating that mediated false memory is not due simply to item differences.     

Enactment enhances integration between verb and noun, but not relational processing, in episodic memory

Improved recall has consistently been demonstrated following motor activation at encoding (SPT), compared to traditional verbal learning (VT). Enhancements of item-specific processing and relational processing have been proposed as possible mechanisms to account for this SPT effect. There is ample evidence supporting the notion of enhanced item-specific processing, however it is still unclear whether enhancement of relational processing contributes to improved recall. In the present study, 2 experiments were designed to address this issue. In Experiment 1, memory under 2 encoding conditions (VT vs. SPT) and 3 recall conditions (free recall vs. category-cued recall vs. verb-cued recall) were studied in 3 large samples (N= 500-600). Experiment 2 replicated the findings of Experiment 1, and controlled for the use of actual objects, short-term memory effects, and carryover effects, in Experiment 1. The results in both experiments showed an interaction between type of encoding and type of recall. Verb-cued recall was affected differently by SPT encoding, as compared to category-cued recall and free recall. The results indicate that enhanced integration between verb and noun is an effect of SPT encoding, whereas enhanced relational processing is not.     

An item gains and losses analysis of false memories suggests critical items receive more item-specific processing than list items

In a repeated testing paradigm, list items receiving item-specific processing are more likely to be recovered across successive tests (item gains), whereas items receiving relational processing are likely to be forgotten progressively less on successive tests. Moreover, analysis of cumulative-recall curves has shown that item-specific processing produces a slower, but steadier rate of recall than relational processing. The authors relied on these findings to determine the type of processing that both list items and critical lures receive in the Deese-Roediger-McDermott false memory procedure. The first 2 experiments revealed that critical lures produced more item gains, but only the list items resulted in a decrease in item losses across successive tests. The critical lures also produced slower but steadier cumulative recall. In Experiments 3 and 4, the critical items were physically presented during study, which resulted in the lures producing progressively fewer losses across successive tests. The authors concluded that critical items receive more item-specific processing than list items but that unless they are presented in the list, they do not become part of participants' organized retrieval scheme.     

Encoding instructions and stimulus presentation in local environmental context-dependent memory studies

Murnane and Phelps (1993) recommend word pair presentations in local environmental context (EC) studies to prevent associations being formed between successively presented items and their ECs and a consequent reduction in the EC effect. Two experiments were conducted to assess the veracity of this assumption. In Experiment 1, participants memorised single words or word pairs, or categorised them as natural or man made. Their free recall protocols were examined to assess any associations established between successively presented items. Fewest associations were observed when the item-specific encoding task (i.e., natural or man made categorisation of word referents) was applied to single words. These findings were examined further in Experiment 2, where the influence of encoding instructions and stimulus presentation on local EC dependent recognition memory was examined. Consistent with recognition dual-process signal detection model predictions and findings (e.g., Macken, 2002; Parks & Yonelinas, 2008), recollection sensitivity, but not familiarity sensitivity, was found to be local EC dependent. However, local EC dependent recognition was observed only after item-specific encoding instructions, irrespective of stimulus presentation. These findings and the existing literature suggest that the use of single word presentations and item-specific encoding enhances local EC dependent recognition.     

Overwriting of phonemic features in serial recall

We tested two explanations of the phonological similarity effect in verbal short-term memory: The confusion hypothesis assumes that serial positions of similar items are confused. The overwriting hypothesis states that similar items share feature representations, which are overwritten. Participants memorised a phonologically dissimilar list of CVC-trigrams (Experiment 1) or words (Experiment 2 and 3) for serial recall. In the retention interval they read aloud other items. The material of the distractor task jointly overlapped one item of the memory list. The recall of this item was impaired, and the effect was not based on intrusions from the distractor task alone. The results provide evidence for feature overwriting as one potential mechanism contributing to the phonological similarity effect.     

Gains and losses in action memory.

Enacting action phrases (SPT for subject-performed task) produces better free recall than only learning the phrases verbally (VT for verbal task). A widespread explanation of the enactment effect is based on the distinction between item-specific and relational information. There is widespread agreement that the main reason is the excellent item-specific encoding by enactment. However, there is little direct evidence in the case of free recall. The role of relational information is less clear. We suggest that content-based relational encoding is better in VTs than in SPTs. In three experiments, in which multiple free recall testing used item gains and losses as indices of item-specific and content-based relational encoding, respectively, these assumptions were confirmed. Consistently more gains (indexing better item-specific encoding) and more losses (indexing poorer relational encoding) were observed in SPTs than in VTs (Experiments 1 and 2). Furthermore, it was demonstrated that the content-based relational information underlying losses is not identical with order-relational information (Experiment 2). In Experiment 3, it was shown that an item-specific orienting task for VTs produced an equivalent number of item gains and losses as did the SPT condition.     

Overwriting of phonemic features in serial recall

We tested two explanations of the phonological similarity effect in verbal short‐term memory: The confusion hypothesis assumes that serial positions of similar items are confused. The overwriting hypothesis states that similar items share feature representations, which are overwritten. Participants memorised a phonologically dissimilar list of CVC‐trigrams (Experiment 1) or words (Experiment 2 and 3) for serial recall. In the retention interval they read aloud other items. The material of the distractor task jointly overlapped one item of the memory list. The recall of this item was impaired, and the effect was not based on intrusions from the distractor task alone. The results provide evidence for feature overwriting as one potential mechanism contributing to the phonological similarity effect.     

Cue utilization following different forms of encoding in mildly, moderately, and severely demented patients with Alzheimer's disease

The ability of patients with Alzheimer's disease (AD) to utilize semantic category cues in order to improve memory performance was examined. Categorizable lists of words or objects were presented under five different encoding conditions: (a) nouns, (b) objects, (c) objects with a semantic orienting question, (d) objects with self-generated motoric acts, and (e) objects with experimenter-instructed motoric acts. Subjects were asked to memorize the items for a free recall test, and were subsequently provided with the category names in a cued recall test. Mildly, moderately, and severely demented AD patients, and a group of normal older adults participated in the study. Results showed that normal older adults and mildly demented AD subjects were able to utilize cues to improve memory performance in all conditions. Moderately demented patients utilized cues in all conditions except in the verbal condition (condition [a]), whereas severely demented patients utilized cues only in the motoric condition (condition [e]). These results suggest that the ability to utilize category cues following a motoric encoding is preserved later in AD than the ability to utilize cues after a semantic encoding.     

Dissociative effects of true and false recall as a function of different encoding strategies

Goodwin, Meissner, and Ericsson (2001) proposed a path model in which elaborative encoding predicted the likelihood of verbalisation of critical, nonpresented words at encoding, which in turn predicted the likelihood of false recall. The present study tested this model of false recall experimentally with a manipulation of encoding strategy and the implementation of the process-tracing technique of protocol analysis. Findings indicated that elaborative encoding led to more verbalisations of critical items during encoding than rote rehearsal of list items, but false recall rates were reduced under elaboration conditions (Experiment 2). Interestingly, false recall was more likely to occur when items were verbalised during encoding than not verbalised (Experiment 1), and participants tended to reinstate their encoding strategies during recall, particularly after elaborative encoding (Experiment 1). Theoretical implications for the interplay of encoding and retrieval processes of false recall are discussed.     

Falsely recalled items are rich in item-specific information

Current theorizing suggests that critical lures in the Deese/Roediger-McDermott (DRM) procedure are often falsely remembered because they have received considerable relational processing (e.g., spreading activation or encoding of gist information). We used a repeated-testing paradigm to assess the amount of item-specific and relational processing given to the list items and the critical lures. Research has shown that items receiving item-specific processing are more likely to be recovered across successive tests. They are also output more slowly but more steadily throughout the recall period. In two experiments, we manipulated the processing performed on list items and then used item gains and cumulative recall curves to assess the amount of item-specific an drelational information encoded for both list items and lures. The results suggest that increasing the relational processing of list items increased item-specific processing of lures, whereas increasing item-specific processing of list items decreased item-specific processing of lures. We conclude that critical lures are typically rich in item-specific information, relative to list items.     

The role of item-specific information for the serial position curve in free recall

The serial position curve in free recall of a list of action phrases differs depending on whether the phrases were memorized by listening/reading (verbal task; VT) or by additionally enacting the denoted actions (subject-performed task; SPT). In VTs there is a clear primacy effect and a short recency effect. In SPTs there is no primacy effect but an extended recency effect. H. D. Zimmer, T. Helstrup, and J. Engelkamp (2000) assumed that SPTs provide excellent item-specific information, which leads to an automatic pop-out of the items presented last. In the present study, the authors assumed that good item-specific encoding generally enhances the recency effect and that it hinders rehearsal processes and thereby reduces the primacy effect. This assumption was confirmed. An item-specific orienting task leads to parallel serial position curves in VTs and SPTs with no primacy effect but a clear recency effect. Moreover, the same serial position effects were shown with nouns as learning material. An item-specific orienting task changes the classical U-shaped serial position curve with verbal material and leads to the disappearance of the primacy and the enhancement of the recency effect.     

The low-frequency encoding disadvantage: Word frequency affects processing demands

Low-frequency words produce more hits and fewer false alarms than high-frequency words in a recognition task. The low-frequency hit rate advantage has sometimes been attributed to processes that operate during the recognition test (e.g., L. M. Reder et al., 2000). When tasks other than recognition, such as recall, cued recall, or associative recognition, are used, the effects seem to contradict a low-frequency advantage in memory. Four experiments are presented to support the claim that in addition to the advantage of low-frequency words at retrieval, there is a low-frequency disadvantage during encoding. That is, low-frequency words require more processing resources to be encoded episodically than high-frequency words. Under encoding conditions in which processing resources are limited, low-frequency words show a larger decrement in recognition than high-frequency words. Also, studying items (pictures and words of varying frequencies) along with low-frequency words reduces performance for those stimuli.     

The production of false recognition and the associated state of consciousness following encoding in a naturalistic context in aging

Using virtual reality, we implemented a naturalistic variant of the DRM paradigm in young and older adults to evaluate false recall and false recognition. We distinguished false recognition related to the highest semantic association (the critical lures), semantic similarity (i.e. items that belong to the same semantic category), and perceptual similarity (i.e. items that are similar, but not identical in terms of shape or color). The data revealed that younger adults recalled and recognized more correct elements than older adults did while the older adults intruded more critical items than younger adults. Both age groups produced false recognition related to the critical items, followed by perceptually and then semantically related items. False recognitions were highly recollective as they were mainly associated with a sense of remembering, even more so in older adults than in young adults. The decline of executive functions and working memory predicted age-related increases in false memories.     

Odor discrimination and recognition memory as a

The role of olfactory familiarization in short-term recognition of odors was investigated. Subjects were asked to make qualitative similarity judgments regarding either identical or dissimilar odors delivered in pairs. Except for control groups, subjects got familiarized with either the first (target) or the second (distractor) or both odors from a pair. Groups also differed according to the number of familiarization sessions—one, two, or three—taking place prior to the discrimination judgments. There was no significant influence of familiarization on correct recognition scores for pairs of identical odors. The most salient finding was a marked decrease of false alarms as a function of the number of familiarization sessions, which evidenced a positive effect of familiarization on discrimination for pairs of dissimilar odors. These judgments were not dependent on an intensity criterion. False alarms did not vary according to whether subjects had been familiarized with the target or the distractor or both odors from a pair. A positive correlation found between discrimination performances and the number of odors correctly remembered as being presented during familiarization suggested that familiarization resulted in long-term storing of memory traces for familiarized odors. Since familiarization was effective despite conditions unfavorable to the use of semantic encoding, the results argue in favor of a predominantly perceptual encoding of odors in the investigated task.     

Developmental differences in episodic memory across school ages: evidence from enacted events performed by self and others

The aim of this study was to examine action memory as a form of episodic memory among school-aged subjects. Most research on action memory has focused on memory changes in adult populations. This study explored the action memory of children over time. A total of 410 school-aged child participants, comprising 201 girls and 208 boys in four age groups (8, 10, 12, and 14), were included in this study. We studied two forms of action encoding, subject-performed tasks (SPTs) and experimenter-performed tasks (EPTs), which were compared with one verbal encoding task as a control condition. At retrieval, we used three memory tests (free recall, cued recall, and recognition). We observed significant differences in memory performance in children aged 8–14 years with respect to free recall and cued recall but not recognition. The largest memory enhancement was observed for the SPTs in the 8–14-year-old participants under all test conditions. Participants performed equally well on the free recall of SPTs and EPTs, whereas they displayed better performances on the cued recall and recognition of SPTs compared to EPTs. The strategic nature of SPTs and the distinction between item-specific information and relational information are discussed.