Conceptual implicit memory and environmental context

Changes in environmental context between encoding and retrieval often affect explicit memory but research on implicit memory is equivocal. One proposal is that conceptual but not perceptual priming is influenced by context manipulations. However, findings with conceptual priming may be compromised by explicit contamination. The present study examined the effects of environmental context on conceptual explicit (category-cued recall) and implicit memory (category production). Explicit recall was reduced by context change. The implicit test results depended on test awareness (assessed with a post-test questionnaire). Among test-unaware participants, priming was equivalent for same-context and different-context groups, whereas for the test-aware, the same-context group produced more priming. Thus, when explicit contamination is controlled, changes in environmental context do not impair conceptual priming. Context dependency appears to be a general difference between implicit and explicit memory rather than a difference between conceptual and perceptual implicit memory. Finally, measures of mood indicated no changes in affect across contexts, arguing against mood mediation for the context effects in explicit recall.     

Generation disrupts memory for intrinsic context but not extrinsic context

Although generation typically enhances item memory, the effect is subject to a number of theoretically important limitations. One potential limitation concerns context memory but there has been debate about whether generation actually enhances or disrupts memory for contextual details. Five experiments assessed the effect of generation on context memory for perceptual attributes of the study stimulus (intrinsic context). The results indicate that despite enhancing item memory, generation disrupts memory for intrinsic context. This result generalized over different intrinsic details (print colour and font), different generation manipulations, and several methodological factors identified in earlier research as potential moderators of this negative generation effect. Despite the negative generation effect on intrinsic context, contextual details external to the target item (extrinsic context) are not disrupted. In a sixth experiment, a visually based generation task (letter transposition) enhanced context memory for the extrinsic detail of location. Coupled with earlier research, the results indicate that generation disrupts context memory for intrinsic details but either does not harm or enhances memory for extrinsic context.     

The role of context specificity in learning: the effects of training context on explosives detection in dogs

Various experiments revealed that if an animal learns a stimulus–response–reinforcer relationship in one context and is then tested in another context there is usually a lessening of stimulus control, and the same discriminative stimuli that reliably controlled the behavior in the first context will have less effect in the new context. This reduction in performance is known as the context shift effect. The effect of changing context on the probability of detecting explosives was investigated in seven highly trained explosives detection dogs (EDDs). In experiment 1 the dogs were trained alternately on path A, which always had five hidden explosives, and on a very similar path B, which never had any explosives. Within a few sessions the dogs showed a significant decrease in search behavior on path B, but not on path A. In experiment 2 the same dogs were trained only on path B with a target density of one explosive hidden every 4th day. The probability of the dogs now detecting the explosive was found to be significantly lower than in experiment 1. In experiment 3 the effect of the low target density as used in experiment 2 was investigated on a new but very similar path C. Both the detection probability for the one explosive every 4th day on the new path and the motivation to search were significantly higher than found in experiment 2. Finally, in experiment 4, an attempt was made to recondition the dogs to search on path B. Although trained for 12 daily sessions with one explosive hidden every session, the dogs failed to regain the normal levels of motivation they had shown on both new paths and on the paths that they knew usually contained explosives. The findings reveal that even a very intensively trained EDD will rapidly learn that a specific stretch of path does not contain explosives. The dog will then be less motivated to search and will miss newly placed targets. This learning is specific to the formerly always-clean path and is to some extent irreversible. However, the dog will search and detect normally on new paths even if they are very similar to the always-clean path. The data are discussed in terms of variables affecting renewal. The results suggest that following training designed to make a behavior context independent, any extinction training will not generalize beyond that specific context used during the extinction training. In addition, if the behavior is extinguished in a specific context, it will be very difficult to restore that behavior in that context. These conclusions should be considered by anyone attempting to extinguish well-established trans-context behaviors.This research reports portions of a doctoral dissertation submitted by Irit Gazit to Tel Aviv University.     

The impact of beliefs about face recognition ability on memory retrieval processes in young and older adults

This study examined whether beliefs about face recognition ability differentially influence memory retrieval in older compared to young adults. Participants evaluated their ability to recognise faces and were also given information about their ability to perceive and recognise faces. The information was ostensibly based on an objective measure of their ability, but in actuality, participants had been randomly assigned the information they received (high ability, low ability or no information control). Following this information, face recognition accuracy for a set of previously studied faces was measured using a remember–know memory paradigm. Older adults rated their ability to recognise faces as poorer compared to young adults. Additionally, negative information about face recognition ability improved only older adults' ability to recognise a previously seen face. Older adults were also found to engage in more familiarity than item-specific processing than young adults, but information about their face recognition ability did not affect face processing style. The role that older adults' memory beliefs have in the meta-cognitive strategies they employ is discussed.     

Olfactory context and memory retrieval in 3-month-old infants

Three experiments examineed whether olfactory stimuli can produce context-dependent effects in infant memory. In eash, 3-month-old infants learned to kick to control the movement of an overhead modile in the presence of an ambient odor. Retention was assessed 1, 3, or 5 days later. During the retention test, the olfactory context was either the same odor, a different odor, or “no odor.” At 1 day, infants exhibited retention when tested in the presence of the same odor. Infants in the no odor condition exhibited partial retention, whereas memory retrieval was completely disrupted for infants tested in the presence of the different odor. After the 3- and 5-day intervals, all groups showed forgetting. These results were not consistent with recent studies of 3-month-old infants trained and tested in the presence of a distinctive visual and auditory context. The findings suggest that olfactory stimuli are a silent feature of the environment for 3-month-old infants, but that they function as context cues in a way that differs from other sensory modalities.     

Working memory capacity predicts the beneficial effect of selective memory retrieval

Selective retrieval of some studied items can both impair and improve recall of the other items. This study examined the role of working memory capacity (WMC) for the two effects of memory retrieval. Participants studied an item list consisting of predefined target and nontarget items. After study of the list, half of the participants performed an imagination task supposed to induce a change in mental context, whereas the other half performed a counting task which does not induce such context change. Following presentation of a second list, memory for the original list's target items was tested, either with or without preceding retrieval of the list's nontarget items. Consistent with previous work, preceding nontarget retrieval impaired target recall in the absence of the context change, but improved target recall in its presence. In particular, there was a positive relationship between WMC and the beneficial, but not the detrimental effect of memory retrieval. On the basis of the view that the beneficial effect of memory retrieval reflects context-reactivation processes, the results indicate that individuals with higher WMC are better able to capitalise on retrieval-induced context reactivation than individuals with lower WMC.     

Transfer of old ‘reactivated’ memory retrieval cues in rats

The present studies examined whether the retrieval of an old ‘reactivated’ memory could be brought under the control of new contextual cues. In Experiment 1 rats trained in one context were exposed to different contextual cues either immediately, 60 or 120 min after a cued reactivation of the training memory. When tested in the shifted context, subjects exposed shortly after reactivation treated the shifted context as the original context. This transfer diminished with longer post-reactivation delays. Experiment 2 replicated the basic finding and demonstrated that the transfer of the old retrieval cues was specific to the contextual cues present during exposure. These findings are consistent with previous research [i.e., Briggs, J. F., Fitz, K. I., & Riccio, D. C. (in press). Transfer of memory retrieval cues in rats. Psychonomic Bulletin & Review] showing the transfer of retrieval cues for a new memory, and demonstrating a similarity (in this case) between newly acquired and old reactivated memories.     

Forgotten but not gone: Context effects on recognition do not require explicit memory for context

Context effects on recognition memory provide an important indirect assay of associative learning and source memory. Neuropsychological studies have indicated that such context effects may obtain even if the contexts themselves are not remembered—for example, in individuals impaired on direct tests of memory for contextual information. In contrast, a recent study indicated that the effects of temporal context reinstatement on visual recognition obtain only when the contextual information itself was explicitly recollected. Here we report that the effects of reinstatement of spatial-simultaneous context on visual object recognition memory obtain irrespective of whether those context stimuli are explicitly recognized. We suggest that spatial-simultaneous context effects might be based on ensemble unitization of target and context stimuli at encoding, whereas temporal context effects may require recollective processes.     

The influence of story context on a working memory span task

The purpose of the present study was to examine factors that could influence whether recall performance in the reading span task (Daneman & Carpenter, 1980 Daneman, M. and Carpenter, P. 1980. Individual differences in working memory and reading. Journal of Verbal Learning and Verbal Behavior, 19: 450–466. [Crossref] , [Google Scholar]) would benefit from the contextual information from the sentences in the processing component of the task. More specifically, we investigated whether people would benefit from sentence sets that formed short stories or when the entire span task was one continuous story. Overall, there was a clear benefit for contextually related sentence sets (i.e., the story span tasks) compared to the traditional reading span task. However, the benefit was eliminated when the entire set formed one continuous story. These results support the recall reconstruction hypothesis for working memory (Towse, Cowan, Hitch, & Horton, 2008 Towse, J. N., Cowan, N., Hitch, G. J. and Horton, N. J. 2008. The recall of information from working memory: Insights from behavioural and chronometric perspectives. Experimental Psychology, 55: 371–383. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]), which suggests that people may strategically use the content of the sentences from the processing component of the reading span task as memorial cues to reconstruct the target words of the storage component. However, this benefit is constrained to scenarios when the contextual cues are unique to a specific set.     

The notion of contextual locking: Previously learnt items are not accessible as such when appearing in a less common context

We examined the effect of context on the learning of spatial coding in four experiments. Two partially overlapping sets of stimuli, which had the very same stimulus–response spatial coding, were presented in unique contexts. Results show contextual locking—that is, response times to the very same item in a more common context (80%) were significantly shorter than those in a less common context (20%). Contextual locking was obtained both when the context was more salient (Experiments 1 and 2) and less salient (Experiments 3 and 4). In addition, results were obtained even when contextualization seemed less necessary (Experiments 2 and 4). Binding of information to context is discussed in relation to chunking, transfer effects, and practical applications pertaining to professional training.     

The effect of encoding time on retention by infants and young children

Using a Visual Recognition Memory (VRM) procedure, we examined the effect of encoding time on retention by 1- and 4-year olds. Irrespective of age, shorter familiarization time reduced retention, and longer familiarization time prolonged retention. The amount of familiarization that yielded retention after a given delay decreased as a function of age.     

Effect of study context on item recollection

We examined how visual context information provided during encoding, and unrelated to the target word, affected later recollection for words presented alone using a remember–know paradigm. Experiments 1A and 1B showed that participants had better overall memory—specifically, recollection—for words studied with pictures of intact faces than for words studied with pictures of scrambled or inverted faces. Experiment 2 replicated these results and showed that recollection was higher for words studied with pictures of faces than when no image accompanied the study word. In Experiment 3 participants showed equivalent memory for words studied with unique faces as for those studied with a repeatedly presented face. Results suggest that recollection benefits when visual context information high in meaningful content accompanies study words and that this benefit is not related to the uniqueness of the context. We suggest that participants use elaborative processes to integrate item and meaningful contexts into ensemble information, improving subsequent item recollection.     

A timing-specific memory distortion effect in young children

It has been suggested that there are systematic distortions in children's memory for temporal durations, such that children's memory is not just less accurate than that of adults but qualitatively different. Experiment 1 replicated the memory distortion effect by demonstrating developmental change in the tendency to confuse a reference duration with one that is shorter rather than longer than it. When the long-term memory demands of the task were reduced by providing reminders of the reference duration on every trial, there were no such qualitative changes in error patterns (Experiment 2). Further evidence for developmental changes in memory distortion was found in the temporal generalization task of Experiment 3, in which stimuli were spaced logarithmically rather than linearly. In Experiment 4, a similar distortion pattern was absent in a task in which children made judgments about the pitch rather than the duration of stimuli, suggesting the effect may be specific to time estimation.     

Context learning and the effect of context on memory retrieval in Lymnaea

Aerial respiratory behavior in Lymnaea was operantly conditioned so that the animals perform aerial respiration significantly less often. Using the standard training procedure (pond water made hypoxic by bubbling N₂ through it) both food-deprived and fed animals learned and exhibited long-term memory (LTM). However, food-deprived animals exhibited neither learning nor memory when trained under a condition in which the hypoxic pond water also contained a food odorant (carrot, the food-odorant procedure). Fed animals, however, learned and exhibited LTM with the food-odorant procedure. Thus, the presence of the food odorant per se did not prevent learning or the establishment of LTM. Further experimentation, however, revealed that the ability of the snails to have recall (i.e., memory) for the learned behavior was dependent on the context in which memory was tested. That is, if animals were trained with the food-odorant procedure they could only exhibit recall if tested in the food-odorant context and vice versa with the standard training procedure. Thus, although fed animals could learn and show LTM with either training and testing procedure, LTM could only be seen when they were tested in the context in which they were trained.     

Context reinstatement and memory for intrinsic versus extrinsic context: The role of item generation at encoding or retrieval

According to many theoretical accounts, reinstating study context at the time of test creates optimal circumstances for item retrieval. The role of context reinstatement was tested in reference to context memory in several experiments. On the encoding phase, participants were presented with words printed in two different font colors (intrinsic context) or two different sides of the computer screen (extrinsic context). At test, the context was reinstated or changed and participants were asked to recognize words and recollect their study context. Moreover, a read‐generate manipulation was introduced at encoding and retrieval, which was intended to influence the relative salience of item and context information. The results showed that context reinstatement had no effect on memory for extrinsic context but affected memory for intrinsic context when the item was generated at encoding and read at test. These results supported the hypothesis that context information is reconstructed at retrieval only when context was poorly encoded at study.     

The effect of emotion-focused orientation at retrieval on emotional memory in young and older adults

This study examines how emotion-focused orientation at retrieval affects memory for emotional versus neutral images in young and older adults. A total of 44 older adults (ages 61–84 years, M=70.00, SD=5.54) and 43 young adults (ages 17–33 years, M=20.58, SD=3.72) were tested on their free recall and forced-choice recognition of images. At retrieval the emotion-focused orientation was manipulated by instructing participants to focus on emotion-related information (i.e., emotional content of images and the emotional reactions evoked by the images). In the control conditions participants were either instructed to focus on visual information or not provided any specific orientation instruction. In free recall but not forced-choice recognition, the emotion-focused orientation increased young adults’ positivity bias and thus wiped out their superior negativity bias. However, the emotion-focused orientation did not affect older adults’ emotional memory. The data suggest that young adults activate and prioritise emotional goals in response to external demand during intentional information processing whereas older adults seem to spontaneously tune themselves to emotional goals.     

The effect of emotion-focused orientation at retrieval on emotional memory in young and older adults

This study examines how emotion-focused orientation at retrieval affects memory for emotional versus neutral images in young and older adults. A total of 44 older adults (ages 61-84 years, M=70.00, SD=5.54) and 43 young adults (ages 17-33 years, M=20.58, SD=3.72) were tested on their free recall and forced-choice recognition of images. At retrieval the emotion-focused orientation was manipulated by instructing participants to focus on emotion-related information (i.e., emotional content of images and the emotional reactions evoked by the images). In the control conditions participants were either instructed to focus on visual information or not provided any specific orientation instruction. In free recall but not forced-choice recognition, the emotion-focused orientation increased young adults' positivity bias and thus wiped out their superior negativity bias. However, the emotion-focused orientation did not affect older adults' emotional memory. The data suggest that young adults activate and prioritise emotional goals in response to external demand during intentional information processing whereas older adults seem to spontaneously tune themselves to emotional goals.     

Dissociating the two faces of selective memory retrieval

Research in the past four decades has repeatedly shown that selective retrieval of some (non-target) memories can impair subsequent retrieval of other (target) information, a finding known as retrieval-induced forgetting. More recently, however, there is evidence that selective retrieval can both impair and enhance recall of related memories (K-H. T. Bäuml & Samenieh, 2010). To identify possible experimental dissociations between the detrimental and the beneficial effects of memory retrieval, we examined retrieval dynamics in listwise directed forgetting, varying the delay between preceding non-target and subsequent target recall. When target recall immediately followed non-target recall, we replicated the prior work and found detrimental effects of memory retrieval on to-be-remembered items but beneficial effects on to-be-forgotten items. In contrast, when a delay was introduced between non-target and target recall, the detrimental effects were present but the beneficial effects were absent. The results demonstrate a first experimental dissociation between the two effects of memory retrieval. They are consistent with a recent two-factor account of the two faces of selective memory retrieval.     

The influence of one memory retrieval on a subsequent memory retrieval

Ss produced an instance of a category and following zero or two intervening items produced a second instance of the same category. The second instance was produced more quickly than the initial instance. This finding, in conjunction with other data reported in the paper, indicate that the reduction in latency for the second instance is due mostly to a reduction in the rate with which the category is searched.     

The development of metamemory monitoring during retrieval: the case of memory strength and memory absence

This research examined the development of the ability to monitor memory strength and memory absence at retrieval. In two experiments, 7-year-olds, 10-year-olds, and adults enacted and imagined enacting a series of bizarre and common actions. Two weeks later, they completed a memory test in which they were asked to determine whether each action had been enacted, had been imagined, or was novel and to provide a confidence judgment for each response. Results showed that participants across age groups successfully monitored differences in strength between memories for enacted actions and memories for imagined actions. However, compared with 10-year-olds and adults, 7-year-olds exhibited deficits in monitoring of differences in memory strength among imagined actions as well as deficits in monitoring memory absence. Results underscore metamemory developments that have important implications for memory accuracy.