Repetition and laterality effects on recognition memory for words and pictures*

Recognition memory for a list of words was tested by presenting a series of items with Ss instructed to make positive responses to targets (list items) and negative responses to distractors (nonlist items). The test items were either words or pictures, and they were presented tachistoscopically either to the left or right visual field. The results showed mean response latencies to be generally faster for stimuli presented to the right visual field. Response times were faster for target and distractor stimuli on their second test presentations than on initial tests, but this effect was much larger for targets. Repetitions were shown to decrease the amount of time necessary to execute the stimulus encoding and initial retrieval stages of recognition. This was also true, although to a lesser extent, if different stimulus forms (words or pictures) were used on the two tests. Subsequent recognition stages, including memory search and decision processes. were apparently independent of test stimulus form.     

Homogeneity computation: How interitem similarity in visual short-term memory alters recognition

Visual short-term recognition memory for multiple stimuli is strongly influenced by the study items’ similarity to one another—that is, by their homogeneity. However, the mechanism responsible for this homogeneity effect has remained unclear. We evaluated competing explanations of this effect, using controlled sets of Gabor patches as study items and probe stimuli. Our results, based on recognition memory for spatial frequency, rule out the possibility that the homogeneity effect arises because similar study items are encoded and/or maintained with higher fidelity in memory than dissimilar study items are. Instead, our results support the hypothesis that the homogeneity effect reflects trial-by-trial comparisons of study items, which generate a homogeneity signal. This homogeneity signal modulates recognition performance through an adjustment of the subject’s decision criterion. Additionally, it seems the homogeneity signal is computed prior to the presentation of the probe stimulus, by evaluating the familiarity of each new stimulus with respect to the items already in memory. This suggests that recognition-like processes operate not only on the probe stimulus, but on study items as well.     

The relationship between repetition and depth of processing

The relationship between depth of information processing and stimulus repetitions was investigated using a simultaneous category judgment task. Several levels of processing were defined involving (1) physically identical items, (2) physically different but same-name items, (3) different items from the same semantic category, and (4) items from different categories. Stimulus pairs were represented by words and pictures, and each pair was presented one, three, or five times. Response times for categorization judgments increased with the level of processing and decreased with repetitions. Repetitions produced greater facilitation for decisions at deeper levels of processing. In a final incidental recall task, more items were remembered from category-same trials than from same-item trials, but level of processing did not interact with number of presentations. Repetitions produced an equivalent increase in final recall probability for items involved in all decision types, indicating that distributed repetitions can lead to the formation of stronger memory traces at several levels of processing.     

An attentional blink for nontargets?

In a typical attentional blink experiment, viewers try to detect two target items among distractors in a Rapid Serial Visual Presentation (RSVP): processing of the first target impairs participants' ability to recall a subsequent target at short stimulus onset asynchronies (SOAs). However, little is known about whether target detection interferes with memory for nontarget items. To answer this question, in two experiments, we employed a novel dual-task procedure: participants searched for a word target (e.g., "a four-footed animal") and then were tested for recognition of nontarget words. Detection of the target word, which was present on half the trials, produced a standard attentional blink effect on memory for nontarget words, with lag 1 sparing followed by an attentional blink at longer lags. This result shows that target processing has a generalized effect on processing of later events, not only other targets.     

故事情境下真实记忆与虚假记忆的活动差异

以故事情境为实验材料,采用学习再认实验范式,通过操纵再认靶词与故事情境的关联性考察了情境故事对关联虚假记忆和真实再认神经活动的影响。结果发现：在记忆再认的熟悉性加工和回想性加工阶段,虚假记忆与真实记忆所诱发FN400和LPC成分走向一致;在额叶后提取阶段,虚假再认所诱发的晚慢成分波幅大于真实再认。结果说明：情境性关联虚假记忆与真实记忆表现出相似的熟悉性和回想性加工,但在后期需耗费额外的加工资源进行成功的提取。     

Bias in self-motion perceived speed can enhance episodic memory

Prior experiences of a stimulus facilitate reprocessing of that stimulus on a subsequent occasion. This relative ease and speed with which information is processed is defined as fluency and can constitute a basis for memory judgment. Fluency can also be manipulated on line by perceptual bias (e.g., levels of noise), leading to an increase in recognition for items processed more fluently (e.g., items with less noise). Previous experiments using Remember-Know paradigm have shown an impact of perceptual fluency only on familiarity and not on recollection. Recent episodic memory models have postulated a strong link between episodic memory and spatial processes, especially with egocentric updating (Gomez et al. in Acta Psychol 132(3):221-227, 2009). The present experiment was conducted to determine whether self-motion fluency affects recognition performance and particularly has an impact on "Remember" responses. Thirty participants learned a 4-min path movie and then had to recognize among short paths if they were part of the learned path, followed by a Remember-Know procedure for recognized items. Self-motion fluency was manipulated with the presence of nimble acceleration applied on a small part of the recognition paths. Results show that the presence of a self-motion fluency increases significantly the proportion of remember responses solely on learned paths. This study spotlights for the first time a specific fluency effect on recollection and indicates an implication of egocentric-updating processing in episodic memory retrieval.     

Behavioral and neurophysiological correlates of episodic coding,proactive interference,and list length effects in a running span verbal working memory task

Updating refers to (1) discarding items from, (2) repositioning items in, and (3) adding items to a running working memory span. Our behavioral and fMRI experiments varied three factors: trial length, proactive interference (PI), and group integrity. Group integrity reflected whether the grouping of items at the encoding stage was violated at discarding. Behavioral results were consistent with the idea that updating processes have a relatively short refractory period and may not fatigue, and they revealed that episodic information about group context is encoded automatically in working memory stimulus representations. The fMRI results did not show evidence that updating requirements in a task recruit executive control processes other than those supporting performance on nonupdating trials. They did reveal an item-accumulation effect, in which signal increased monotonically with the number of items presented during the trial, despite the insensitivity of behavioral measures to this factor. Behavioral and fMRI correlates of PI extended previous results and rejected an alternative explanation of PI effects in working memory.     

Elaborative processing and conjunction errors in recognition memory

Four experiments were conducted in order to examine the influence of elaborative processing at encoding on recognition memory conjunction lure errors. In these experiments, participants generated cues for compound words as wholes (e.g., haywire) or as separate entities (e.g., hay, wire). Studied words were re-presented in exact form (old) or recombined to form conjunction lures on the recognition test. Participants were asked to make old-new judgments and to indicate whether they had rejected items judged to be new because of recall of a studied item or because of lack of familiarity with an item. The results suggested that recall-to-reject processing and conjunction lure familiarity increased with both types of generation, although generation of cues for compound words as a whole did not influence conjunction lure error rates. An emphasis on processing each constituent of a compound word during encoding increased the familiarity of those constituents more than generation of a compound word as a whole, resulting in an increase in conjunction lure errors. These results suggest that both familiarity and recollection-based monitoring processes influence conjunction lure errors, and therefore support dual-process theories of recognition memory.     

Identifying the Basis for the Word Frequency Effect in Recognition Memory

Abstract

Recent theories of recognition memory have identified two bases on which recognition-memory judgments may be made: recollection, which involves retrieval of contextual information from an earlier episode of stimulus presentation; and familiarity, which is distinguished by a general sense of familiarity in the absence of recollection. Four experiments were conducted to test whether the word frequency effect (WFE) in recognition memory (superior performance with low- in comparison with high-frequency targets) results from recollection-based processes, familiarity-based processes, or both. In two of the experiments, superior memory for aspects of the study context was found for low-frequency in comparison with high-frequency words, suggesting frequency-related differences in recollection. The other two experiments used Jacoby's (1991) inclusion/exclusion paradigm to provide estimates of the contribution of recollection and familiarity to recognition. In both experiments the data suggested that the WFE is primarily a recollection-based phenomenon. These findings suggest that the recognition memory WFE for old items results primarily from the effects of word frequency on recollection. The implications of these findings for theories of recognition memory are discussed.     

Encoding and retrieval processes in normal children and retarded adolescents

Information processing capabilities of normal and retarded individuals were studied within the context of a modified Sternberg recognition memory task. Presentation of items in the memory set was self-paced, and stimulus exposure times and response latencies were recorded.It was found that normal and retarded individuals spent the same amount of time processing subspan lists during input to the memory system; however, the normal subjects spent less time retrieving information from that system than did the retarded subjects. Part of the superiority of normal subjects was attributable to their higher scanning speeds during the stimulus comparison stage of memory retrieval. The scanning strategy of normal and retarded subjects, on the other hand, was found to be the same: serial and exhaustive. It was further demonstrated that the binary decision stage of retrieval was not related to differences in intelligence.     

Source memory that encoding was self-referential: the influence of stimulus characteristics

Decades of research suggest that encoding information with respect to the self improves memory (self-reference effect, SRE) for items (item SRE). The current study focused on how processing information in reference to the self affects source memory for whether an item was self-referentially processed (a source SRE). Participants self-referentially or non-self-referentially encoded words (Experiment 1) or pictures (Experiment 2) that varied in valence (positive, negative, neutral). Relative to non-self-referential processing, self-referential processing enhanced item recognition for all stimulus types (an item SRE), but it only enhanced source memory for positive words (a source SRE). In fact, source memory for negative and neutral pictures was worse for items processed self-referentially than non-self-referentially. Together, the results suggest that item SRE and source SRE (e.g., remembering an item was encoded self-referentially) are not necessarily the same across stimulus types (e.g., words, pictures; positive, negative). While an item SRE may depend on the overall likelihood the item generates any association, the enhancing effects of self-referential processing on source memory for self-referential encoding may depend on how embedded a stimulus becomes in one’s self-schema, and that depends, in part, on the stimulus’ valence and format. Self-relevance ratings during encoding provide converging evidence for this interpretation.     

Bias in self-motion perceived speed can enhance episodic memory

Prior experiences of a stimulus facilitate reprocessing of that stimulus on a subsequent occasion. This relative ease and speed with which information is processed is defined as fluency and can constitute a basis for memory judgment. Fluency can also be manipulated on line by perceptual bias (e.g., levels of noise), leading to an increase in recognition for items processed more fluently (e.g., items with less noise). Previous experiments using Remember–Know paradigm have shown an impact of perceptual fluency only on familiarity and not on recollection. Recent episodic memory models have postulated a strong link between episodic memory and spatial processes, especially with egocentric updating (Gomez et al. in Acta Psychol 132(3):221–227, 2009). The present experiment was conducted to determine whether self-motion fluency affects recognition performance and particularly has an impact on “Remember” responses. Thirty participants learned a 4-min path movie and then had to recognize among short paths if they were part of the learned path, followed by a Remember–Know procedure for recognized items. Self-motion fluency was manipulated with the presence of nimble acceleration applied on a small part of the recognition paths. Results show that the presence of a self-motion fluency increases significantly the proportion of remember responses solely on learned paths. This study spotlights for the first time a specific fluency effect on recollection and indicates an implication of egocentric-updating processing in episodic memory retrieval.     

Visual laterality patterns for pure- versus mixed-list presentation

In Experiment 1, an overall left visual field advantage for nonverbal form recognition was found in a pure list of forms, but an overall right visual field form recognition advantage was found when the form trials were randomly intermixed with word recognition trials. Form complexity also influenced the form recognition laterality pattern, but the complexity effects were independent of (i.e., additive with) those produced by randomly mixing forms with words. Experiment 2 found that the mixed-list laterality pattern was unchanged by a pretrial cue indicating whether a word or form would follow. Experiments 3 and 4 demonstrated that holding two nouns in memory on each trial in a pure list of forms has much the same effect on laterality pattern as mixing forms with words but that the combined effect of these two variables is no larger than the effect of either variable alone. The entire pattern of results suggests that (a) laterality patterns are caused by the interaction of several factors, (b) the effects of random mixing and concurrent verbal memory are both caused by selective left-hemisphere activation, and (c) the form-complexity effects are caused by some other mechanism--perhaps subtle difference in stimulus codability.     

Episodic intertrial learning of younger and older adults: Effects of word frequency

ABSTRACT

Older adults have a demonstrable episodic memory deficit. The present study aimed to investigate whether the age deficit in episodic memory was influenced by stimulus characteristics known to produce differences in memory performance in younger adults, specifically word frequency. An intertrial paradigm was used whereby participants studied high- or low-frequency lists over several study-test trials, and the loss and gain of individual items was measured across trials; putative measures of consolidation and encoding. The results show that high-frequency words are recalled significantly better than low-frequency words. Older adults acquired high-frequency words at a greater rate across trials than they did for low-frequency words, an effect not evident in the younger adults. Older adults were found to have deficits in both encoding and consolidation as measured by losses and gains of items across trials. The results support the inter-item association theory of the word frequency effect on recall, with the age differences suggesting that memory deficits are sensitive to stimuli characteristics – one interpretation being that the ease of processing of the stimuli at encoding facilitates later recall.     

Novelty effects on recollection and familiarity in recognition memory

Recognition memory is better for novel or distinctive items than for non-novel items. However, it is not known whether these effects reflect changes in recollection or in familiarity-based recognition judgments. Some previous results have indicated that recollection should be more sensitive to novelty than to familiarity, whereas other results have suggested the opposite. We used avon Restorff paradigm in which a small proportion of studied items were made novel by presenting them in a color different from that of the majority of the study items. Memory was tested using a remember-know procedure. Across two experiments, stimulus novelty was found to benefit both recollection and familiarity. The effects on familiarity were observed under intentional and incidental encoding conditions, whereas the effects on recollection were significantly reduced, and no longer significant, under incidental as compared with intentional encoding conditions. Thus, both processes benefit from stimulus novelty, but the extent to which recollection benefits from novelty depends on the encoding condition.     

Out of mind, but not out of sight: Intentional control of visual memory

Does visual information enjoy automatic, obligatory entry into memory, or, after such information has been seen, can it still be actively excluded? To characterize the process by which visual information could be excluded from memory, we used Sternberg’s (1966, 1975) recognition paradigm, measuring visual episodic memory for compound grating stimuli. Because recognition declines as additional study items enter memory, episodic recognition performance provides a sensitive index of memory’s contents. Three experiments showed that an item occupying a fixed serial position in a series of study items could be intentionally excluded from memory. In addition, exclusion does not depend on lowlevel information, such as the stimulus’s spatial location, orientation, or spatial frequency, and does not depend on the precise timing of irrelevant information, which suggests that the exclusion process is triggered by some event during a trial. The results, interpreted within the framework of a summed similarity model for visual recognition, suggest that exclusion operates after considerable visual processing of the to-be-excluded item.     

Forgetting is effortful: Evidence from reaction time probes in an item-method directed forgetting task

Reaction time (RT) was measured in response to visual detection probes embedded within an item-method directed forgetting paradigm. In Experiment 1, study words were presented individually followed by an instruction to remember (R) or forget (F). Probes were presented at stimulus onset asynchronies (SOAs) of 1,400, 1,800, or 2,600 msec in relation to the study word or memory instruction. After the study trials, a yes-no recognition task measured retention of R and F words. Experiment 2 added a no-word control condition and no-probe catch trials. In both experiments, post-F probe RTs were longer than post-R probe RTs at early SOAs. Confirming that participants attended to the memory instructions, there was a significant directed forgetting effect, with greater recognition of R than of F words. These findings contradict the view that directed forgetting in the item-method paradigm is due to the passive decay of nonrehearsed F items; instead, they are consistent with the view that intentional forgetting in an item-method paradigm occurs via the operation of an active, potentially inhibitory, cognitive process.     

Auditory List Memory in Rhesus Monkeys

Auditory memory of 2 rhesus monkeys was tested in a serial probe recognition task. Lists of four environmental or natural sounds were followed by a retention interval and a test. The test matched one of the list items on half of the trials. The retention interval was varied across sessions. Six experiments showed similar results and changes in the serial position function. At short retention intervals, there was good memory for first list items (primacy effect) and poor memory for last list items. At intermediate retention intervals, memory improved for last list items (recency effect). At long retention intervals (20 s and 30 s), the recency effect was strong, and the primacy effect had dissipated. These auditory primacy and recency effects and their changes with retention interval were opposite to those for visual memory. Implications for processes and mechanisms of memory are discussed.     

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.