Retrieval‐induced forgetting in normal ageing

The retrieval‐induced forgetting (RIF) paradigm was used to assess the integrity of unintentional inhibitory functioning in normal ageing. The paradigm was adapted to explore the RIF effect under conditions that allow us to differentiate the contribution of intentional and automatic retrieval processes to performance. The results showed the presence of equivalent and significant RIF effects in young and older adults, for both the intentional and automatic retrieval performance. These results suggest that unintentional inhibitory processes are spared in normal ageing and confirm that RIF effect is independent of the kind of memory processes involved in task performance.     

Synchrony effects in automatic and controlled retrieval

Using a speeded retrieval procedure, we investigated time-of-day effects in automatic and controlled retrieval. Morning-type adults were tested at either peak (early morning) or off-peak (late afternoon) times on a speeded implicit (Experiment 1) or explicit (Experiment 2) stem completion task. In Experiment 1, retrieval strategies were identified by changes in response speed between a practice phase with rapid retrieval and an implicit memory test phase. Performance based on controlled retrieval (shown by slowdown participants) showed more priming at peak than at off-peak times of day, a finding confirmed in Experiment 2, in which the participants were given intentional retrieval instructions when the materials switched. In contrast, performance based on automatic retrieval (shown by nonslowdown participants) did not differ across peak and off-peak times. The finding suggests a robust synchrony effect in controlled retrieval, but not in automatic retrieval, which does not appear to vary across the day.     

Memory as a function of attention, level of processing, and automatization

The relationships between long-term memory (LTM) modification, attentional allocation, and type of processing are examined. Automatic/controlled processing theory (Schneider & Shiffrin, 1977) predicts that the nature and amount of controlled processing determines LTM storage and that stimuli can be automatically processed with no lasting LTM effect. Subjects performed the following: (a) an intentional learning, (b) a semantic categorization, (c) a graphic categorization, (d) a distracting digit-search while intentionally learning words, and (e) a distracting digit-search while ignoring words. Frequency judgments were more accurate in the semantic and intentional conditions than the graphic condition. Frequency judgments in the digit-search conditions were near chance. Experiment 2 extensively trained subjects to develop automatic categorization. Automatic categorization produced no frequency learning and little recognition. These results also disconfirm the Hasher and Zacks (1979) "automatic encoding" proposal regarding the nature of processing.     

Modes of knowledge acquisition and retrieval in artificial grammar learning

The aim of this study was to conceptualize artificial grammar learning (AGL) in terms of two orthogonal dimensions—the mode of knowledge acquisition and the mode of knowledge retrieval—as was done by Perlman and Tzelgov (2006) for sequence learning. Experiment 1 was carried out to validate our experimental task; Experiments 2–4 tested, respectively, performance in the intentional, incidental, and automatic retrieval modes, for each of the three modes of acquisition. Furthermore, signal detection theory (SDT) was used as an analytic tool, consistent with our assumption that the processing of legality-relevant information involves decisions along a continuous dimension of fluency. The results presented support the analysis of AGL in terms of the proposed dimensions. They also indicate that knowledge acquired during training may include many aspects of the presented stimuli (whole strings, relations among elements, etc.). The contribution of the various components to performance depends on both the specific instruction in the acquisition phase and the requirements of the retrieval task.     

Automatic and controlled components of judgment and decision making

The categorization of inductive reasoning into largely automatic processes (heuristic reasoning) and controlled analytical processes (rule-based reasoning) put forward by dual-process approaches of judgment under uncertainty (e.g., K. E. Stanovich & R. F. West, 2000) has been primarily a matter of assumption with a scarcity of direct empirical findings supporting it. The present authors use the process dissociation procedure (L. L. Jacoby, 1991) to provide convergent evidence validating a dual-process perspective to judgment under uncertainty based on the independent contributions of heuristic and rule-based reasoning. Process dissociations based on experimental manipulation of variables were derived from the most relevant theoretical properties typically used to contrast the two forms of reasoning. These include processing goals (Experiment 1), cognitive resources (Experiment 2), priming (Experiment 3), and formal training (Experiment 4); the results consistently support the author's perspective. They conclude that judgment under uncertainty is neither an automatic nor a controlled process but that it reflects both processes, with each making independent contributions.     

Syntax and intentionality: An automatic link between language and theory-of-mind

Three studies provided evidence that syntax influences intentionality judgments. In Experiment 1, participants made either speeded or unspeeded intentionality judgments about ambiguously intentional subjects or objects. Participants were more likely to judge grammatical subjects as acting intentionally in the speeded relative to the reflective condition (thus showing an intentionality bias), but grammatical objects revealed the opposite pattern of results (thus showing an unintentionality bias). In Experiment 2, participants made an intentionality judgment about one of the two actors in a partially symmetric sentence (e.g., “John exchanged products with Susan”). The results revealed a tendency to treat the grammatical subject as acting more intentionally than the grammatical object. In Experiment 3 participants were encouraged to think about the events that such sentences typically refer to, and the tendency was significantly reduced. These results suggest a privileged relationship between language and central theory-of-mind concepts. More specifically, there may be two ways of determining intentionality judgments: (1) an automatic verbal bias to treat grammatical subjects (but not objects) as intentional (2) a deeper, more careful consideration of the events typically described by a sentence.     

The neural substrates of action retrieval: An examination of semantic and visual routes to action

We report three PET experiments that examine the neural substrates of the conceptual components of action retrieval. In all three experiments, subjects made action or screen-size decisions to familiar objects presented either as pictures or written words (the names ofthe objects). In Experiment 1, a third task was included, requiring a decision on the real-life size of the stimuli. In Experiment 2, a third stimulus type was included, with action and size decisions also performed on pictures of meaningless novel objects. Finally, in Experiment 3, we changed the response mode from a button press to a more explicit movement made with a “manipulandum”. Based on neuropsychological findings, we predicted that when action responses were made to pictures of familiar or novel objects, relative to words, there would be less activation in semantic regions but greater activation in visual, motor, and perhaps parietal cortices. We found that, action relative to screen-size decisions on both pictures and words activated the left hemisphere temporo-frontal semantic system with activation in the left posterior middle temporal cortex specific to action retrieval (Experiment 1). In addition, action retrieval elicited more activation for (1) words than pictures in areas associated with semantics; and (2) novel objects than words or familiar objects in areas associated with pre-semantic object processing. These results are discussed in the context of semantic and visual routes to action retrieval.     

Intentional versus unintentional use of contingencies between perceptual events

In three experiments we studied human ability to use statistical contingencies between visual stimuli (flankers and targets) to improve performance in a letter-digit classification task. We compared the performance of explicitly informed subjects with that of subjects who were told nothing of the contingencies. Simultaneous presentation of flankers and targets (Experiment 1) produced evidence of unintentional contingency use by both informed and uninformed subjects. When stimuli on trialn predicted target stimuli on trialn+1 (Experiment 2) there was no evidence of unintentional processes, but informed subjects showed strong evidence of using intentional prediction strategies. When flanker onset preceded target stimuli presentation (Experiment 3), evidence of contingency use by both informed and uninformed subjects was found, but the data illustrated qualitative differences in response style (e.g., speed-accuracy tradeoffs) between the two groups. Intentional and unintentional uses of contingencies between perceptual events are qualitatively distinct with respect to the time frame in which they can be applied and the performance patterns they produce. Finally, we argue that the unintentional processes studied here are implicit in nature.     

Automatic retrieval in directed forgetting

In two experiments, we investigated the role of automatic retrieval in directed forgetting, using a stem completion test. In each experiment, we compared the performance of an implicit group, a process dissociation procedure (PDP) group, and a group given a speeded response task. The response times of the speeded response group on the stem completion task replicated earlier data in suggesting that this group adopted a purely automatic retrieval strategy. Experiment 1 revealed a directed-forgetting effect on automatic retrieval with the item method, but Experiment 2 revealed no directed-forgetting effect on automatic retrieval with the list method, consistent with the lack of implicit effects with the list method throughout the literature. Both experiments showed lower automatic estimates for the PDP group than for the implicit and speeded response groups, which did not differ. The data are consistent with either a selective rehearsal or an inhibition account of directed forgetting with the list method. The comparison of methods for assessing automatic retrieval is consistent with earlier evidence suggesting that subjects may adopt a generate/recognize strategy when given direct retrieval instructions.     

Associative and similarity-based processes in categorization decisions

Two experiments were directed at distinguishing associative and similarity-based accounts of systematic differences in categorization time for different items in natural categories. Experiment 1 investigated the correlation of categorization time with three measures of instance centrality in a category. Production frequency (PF), rated typicality, and familiarity from category norms for British participants (Hampton & Gardiner, 1983) were used to predict mean categorization times for 531 words in 12 semantic categories. PF and typicality (but not familiarity) were found to make significant and independent contributions to categorization time. Error rates were related only to typicality (apart from errors made to ambiguous or unknown items). Experiment 2 provided a further dissociation of PF and typicality. Manipulating the difficulty of the task through the relatedness of the false items interacted primarily with the effect of typicality on categorization time, whereas, under conditions of easy discrimination, prior exposure to the category exemplars affected only the contribution of PF to the decision time. The dissociation of typicality and PF measures is interpreted as providing evidence that speeded categorization involves both retrieval of associations indexed by PF and a similarity-based decision process indexed by typicality.     

Automatic processing influences free recall: converging evidence from the process dissociation procedure and remember-know judgments

Dual-process theories of retrieval suggest that controlled and automatic processing contribute to memory performance. Free recall tests are often considered pure measures of recollection, assessing only the controlled process. We report two experiments demonstrating that automatic processes also influence free recall. Experiment 1 used inclusion and exclusion tasks to estimate recollection and automaticity in free recall, adopting a new variant of the process dissociation procedure. Dividing attention during study selectively reduced the recollection estimate but did not affect the automatic component. In Experiment 2, we replicated the results of Experiment 1, and subjects additionally reported remember–know–guess judgments during recall in the inclusion condition. In the latter task, dividing attention during study reduced remember judgments for studied items, but know responses were unaffected. Results from both methods indicated that free recall is partly driven by automatic processes. Thus, we conclude that retrieval in free recall tests is not driven solely by conscious recollection (or remembering) but also by automatic influences of the same sort believed to drive priming on implicit memory tests. Sometimes items come to mind without volition in free recall.     

Perirhinal cortex lesions produce retrograde amnesia for spatial information in rats: consolidation or retrieval?

Several lines of evidence in humans and experimental animals suggest that the hippocampus is critical for the formation and retrieval of spatial memory. However, although the hippocampus is reciprocally connected to adjacent cortices within the medial temporal lobe and they, in turn, are connected to the neocortex, little is known regarding the function of these cortices in memory. Here, using a reference spatial memory task in the radial maze, we show that neurotoxic perirhinal cortex lesions produce a profound retrograde amnesia when learning-surgery intervals of 1 or 50 d are used (Experiment 1). With the aim of dissociating between consolidation and retrieval processes, we injected lidocaine either daily after training (Experiment 2) or before a retention test once the learning had been completed (Experiment 3). Results show that reversible perirhinal inactivation impairs retrieval but not consolidation. However, the same procedure followed in Experiment 2 disrupted consolidation when the lidocaine was injected into the dorsal hippocampus. The results of Experiment 4 rule out the possibility that the deficit in retrieval is due to a state-dependent effect. These findings demonstrate the differential contribution of various regions of the medial temporal lobe to memory, suggesting that the perirhinal cortex plays a key role in the retrieval of spatial information for a long period of time.     

Speed of processing explains the picture–word asymmetry in conditional naming

In this study, we investigated picture (Experiments 1 and 2) and word (Experiments 3 and 4) processing using different tasks. In Experiments 1 and 3, easy and difficult conditional naming tasks were compared to a free naming task. In Experiments 2 and 4, easy and difficult conditional naming tasks were compared to easy and difficult manual forced-choice semantic decision tasks. For pictures, we showed that a difficult semantic categorization determined a cost for the conditional naming with respect to the free naming (Experiment 1). Also, we found that the difference in RTs between the easy and difficult conditional naming tasks was much smaller than the difference between the easy and difficult forced-choice semantic decision tasks (Experiment 2). For words, results showed that free reading was faster than easy conditional reading, which in turn was faster than difficult conditional reading (Experiment 3). An analogous pattern of results was obtained when the easy and difficult conditional reading tasks were compared to the easy and difficult forced-choice semantic decision tasks (Experiment 4). Globally, the results showed that whether a cost is observed or not depends upon the relative timing of the classification and name retrieval processes. A theoretical framework has been proposed.     

The integrative action of the cerebral hemispheres

In four experiments, right-handed subjects were asked to identify uppercase letters presented tachistoscopically in the right (R) or left (L) visual field or in both visual fields simultaneously (RL). When R, L, and RL trials were randomized together and RL trials consisted of the same letter in each visual field (Experiments 1 and 2), 11 of 21 male subjects (Experiment 1) and 9 of 18 female subjects (Experiment 2) showed a strong left-visual-field advantage, and the remainder in each experiment showed an equivalently strong right-visual-field advantage. When the RL trials consisted of a different letter in the two visual fields (Experiment 3), a consistent right-visual-field advantage was observed. It is argued that these results reflect predominantly analytical (left-hemisphere) processing of “different” pairs and relatively holistic processing of “same” pairs, which induces a shift toward a right-hemisphere advantage in some subjects. The main purpose of three of the four experiments was to test five probability models of hemispheric integration: (1) statistical summation, which assumes that the hemispheres operate independently; (2) redundancy, which assumes that RL decisions reflect only processing by the more specialized hemisphere; (3) complete dependency, according to which RL decisions are the mean of Rand L decisions; (4) integration, which assumes that R and L decisions can be represented as vectors in a joint RL space; (5) correlation, according to which the Rand L decisions are assumed to be statistically dependent. Whether R, L, and RL trials were randomized together or RL trials were presented in separate blocks, models 1 and 4 could be clearly rejected. In general, the best predictor of RL performance was model 5. It is argued that the hemispheres function as an integrated system in letter identification.     

Memory and judgment: Availability versus explanation-based accounts

Two theories about the relationship between memory and decisions are examined. In an explanation-based model, the organization in memory of decision-relevant information determines decisions. In an availability model, the amount of information sampled from memory that supports competing decisions is crucial. In Experiment 1, subjects read evidence from a legal trial, made decisions, and provided free-recall data. Evidence presentation order was manipulated to produce differences in evidence coherence. When the prosecution evidence order was coherent, the subjects were more likely to choose guilty verdicts, and recall of prosecution evidence, relative to defense evidence, was greater. Thus, both evidence coherence and availability of information in memory could account for the basic findings. In Experiment 2, recall differences were eliminated as a function of evidence order. The results show that verdict effects favoring the more coherent prosecution evidence are obtained even when the relative amounts of prosecution and defense recall are equated across conditions.     

Retrieval practice can eliminate list method directed forgetting

It has recently been shown that retrieval practice can reduce memories’ susceptibility to interference, like retroactive and proactive interference. In this study, we therefore examined whether retrieval practice can also reduce list method directed forgetting, a form of intentional forgetting that presupposes interference. In each of two experiments, subjects successively studied two lists of items. After studying each single list, subjects restudied the list items to enhance learning, or they were asked to recall the items. Following restudy or retrieval practice of list 1 items, subjects were cued to either forget the list or remember it for an upcoming final test. Experiment 1 employed a free-recall and Experiment 1 a cued-recall procedure on the final memory test. In both experiments, directed forgetting was present in the restudy condition but was absent in the retrieval-practice condition, indicating that retrieval practice can reduce or even eliminate this form of forgetting. The results are consistent with the view that retrieval practice enhances list segregation processes. Such processes may reduce interference between lists and thus reduce directed forgetting.     

The power of a story: New,automatic associations from a single reading of a short scenario

The implicit association test (IAT) is typically used to assess nonconscious categorization judgments that are “under control of automatically activated evaluation” (Greenwald, McGhee, & Schwartz, 1998, p. 1464) and that are usually considered independent of explicit judgments. The present study builds on recent work suggesting evidence of short-term modifiability of the IAT effect. Specifically, we show that reading a short text that describes a novel, fictional scenario, within which the to-be-evaluated categories are embedded, can produce substantial and immediate modulations of the IAT effect. This modulation effect does not occur when subjects are simply instructed to think about counterstereotypical associations (Experiment 1A and 1B). In Experiment 2, we use a variant of the IAT to show that scenario modulation cannot be explained in terms of strategic criterion shifts. These results suggest that a newly acquired knowledge structure targeting the abstract, category level can produce behavioral effects typically associated with automatic categorization.     

Linear and nonlinear effects of aging on categorizing and naming faces.

Subjects aged 54-84 performed 5 separate tasks involving various aspects of face processing: structural decisions (1), familiarity decisions (2), semantic decisions (3), first-name decisions (4), and name retrieval (5). For the categorization tasks (1-4), the mean reaction times for the older subjects (over 65) were plotted against the corresponding means for the younger subjects (under 65). This produced a linear function (slope greater than 1, intercept less than 0), providing only partial support for a simple, multiplicative model of cognitive slowing with age. Reaction time distributions were also plotted for each of the 5 tasks (older vs. younger subjects). The resulting functions were almost perfectly linear, with the exception of name retrieval, which was exponential with respect to age. This was attributed to the increased probability of a tip-of-the-tongue state with age caused by insufficient activation at the level of the name information (the final state of face identification).     

Assessment of retrieval strategy in incidental, intentional, and inclusion tests with word-fragment cues

The purpose of this study was to assess retrieval strategy in incidental, intentional, and inclusion tests with word-fragment cues following a levels-of-processing manipulation at study. The results of Exp. 1 showed small levels-of-processing effects in incidental tests, and most subjects reported involuntary rather than voluntary retrieval of study-list words. In an intentional test, although levels of processing had a much greater effect, quite a few subjects also reported involuntary rather than voluntary retrieval of study-list words, and these subjects showed a smaller effect of levels of processing than subjects reporting voluntary retrieval. These results suggest that subjects given instructions for both voluntary and involuntary retrieval of study-list words in an inclusion test might not in fact attempt voluntary retrieval at all, but simply adopt an involuntary retrieval strategy. The results of Exp. 2 provided evidence to support this suggestion. The general implication is that where test contamination refers to subjects' failure to use retrieval strategies in accordance with test instructions, inclusion tests can be contaminated, as well as incidental or intentional tests, and that it is always necessary to obtain converging evidence about the actual strategies subjects use.     

The role of inhibitory control in forgetting semantic knowledge

Previous research has shown that episodic retrieval recruits inhibitory processes that impair memory for related events. We report two experiments examining whether inhibitory processes may also be involved in causing semantic memory lapses. In a semantic retrieval-practice paradigm, subjects were given trials presenting a cue (a homograph in Experiment 1, a category in Experiment 2) linked to many different items in semantic memory. For each cue, subjects used general knowledge to generate no (baseline), one, four, or eight different items of semantic knowledge. Afterward, we determined through an apparently unrelated free-association test whether a critical nonpracticed concept associated to the cue had been inhibited. Both experiments found that generating items from semantic memory suppressed competing concepts, and that this impairment was cue independent. These findings show that inhibitory control processes overcome interference during semantic retrieval and that recruitment of these processes may contribute to semantic forgetting.