Directed forgetting and directed remembering in visual working memory

A defining characteristic of visual working memory is its limited capacity. This means that it is crucial to maintain only the most relevant information in visual working memory. However, empirical research is mixed as to whether it is possible to selectively maintain a subset of the information previously encoded into visual working memory. Here we examined the ability of participants to use cues to either forget or remember a subset of the information already stored in visual working memory. In Experiment 1, participants were cued to either forget or remember 1 of 2 groups of colored squares during a change-detection task. We found that both types of cues aided performance in the visual working memory task but that observers benefited more from a cue to remember than a cue to forget a subset of the objects. In Experiment 2, we show that the previous findings, which indicated that directed-forgetting cues are ineffective, were likely due to the presence of invalid cues that appeared to cause observers to disregard such cues as unreliable. In Experiment 3, we recorded event-related potentials and show that an electrophysiological index of focused maintenance is elicited by cues that indicate which subset of information in visual working memory needs to be remembered, ruling out alternative explanations of the behavioral effects of retention-interval cues. The present findings demonstrate that observers can focus maintenance mechanisms on specific objects in visual working memory based on cues indicating future task relevance. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

How generation affects source memory

Generation effects (better memory for self-produced items than for provided items) typically occur in item memory. Jurica and Shimamura (1999) reported a negative generation effect in source memory, but their procedure did not test participants on the items they had generated. In Experiment 1, participants answered questions and read statements made by a face on a computer screen. The target word was unscrambled, or letters were filled in. Generation effects were found for target recall and source recognition (which person did which task). Experiment 2 extended these findings to a condition in which the external sources were two different faces. Generation had a positive effect on source memory, supporting an overlap in the underlying mechanisms of item and source memory.     

Reading is believing: the truth effect and source credibility

Five experiments explored how source reliability influences people’s tendency to rate statements as more credible when they were encountered earlier (the truth effect). Undergraduates read statements from one reliable source and one unreliable source. Statements read multiple times were perceived as more valid and were more often correctly identified on a general knowledge test than statements read once or not at all. This occurred at varying retention intervals whether the statements originated from a reliable or unreliable source, when people had little memory for the statements themselves or their source, and when the discrediting information about the sources came either before or after reading the facts. While repetition aided recognition and source accuracy, both were unaffected by the reliability of the source. Consistent with the source monitoring framework, familiarity may create an illusion of truth for statements when people lack source-specifying cues, especially cues regarding the reliability of the source.     

视觉工作记忆负载对听觉偏差干扰效应的调控：来自不同外周提示线索的证据

采用线索提示和视听Oddball结合的实验设计, 通过四个实验探讨了外周视线索下视觉工作记忆负载对听觉偏差干扰效应的调控作用。结果表明：(1)操作外周视线索有效性为50%的条件下, 视觉工作记忆负载的增加使得原本抑制无关声音的过程失败, 因此出现了显著的听觉偏差干扰效应; (2)操作外周视线索有效性为80%的条件下, 发现有策略性的注意定向消耗了注意资源, 无视觉工作记忆负载的情况下同样出现听觉偏差干扰, 并且随着工作记忆负载增加偏差干扰效应增强。研究说明视觉工作记忆负载对听觉偏差干扰的调控是有条件性的, 当来自不同感觉通道的无关刺激与目标的加工过程存在重叠时, 视觉工作记忆负载的增加使得听觉偏差干扰效应增强而不是减弱。     

Internal reinstatement hides cuing effects in source memory tasks

Reinstating source details at test often has no impact on source memory. We tested the proposition that participants internally reinstate source cues when such cues are not provided by the experimenter, thus making the external cues redundant. Participants studied words paired with either a male or a female face and were later asked to specify the gender of the face studied with each word. To disrupt the ability to internally reinstate sources, some participants saw eight male faces and eight female faces throughout the study list (multiple-face condition), making it difficult to determine which face should be internally reinstated for uncued test trials. Other participants saw only a single face for each gender (single-face condition), which should facilitate internal reinstatement. Across three experiments, participants in the multiple-face condition showed improved source discrimination when the studied faces were reinstated at test, as compared to uncued trials. In contrast, participants in the single-face condition showed no effect of the face cues. Moreover, the cuing effect for the multiple-face condition disappeared when the test structure facilitated internal reinstatement. Overall, the experiments support the contention that internal reinstatement is a natural part of source retrieval that can mask the effects of external cues.     

Metacognition and part-set cuing: Can interference be predicted at retrieval?

Although prior research has examined predictions of memory performance under conditions of interference at encoding, predictions of memory performance have not been examined for interference introduced via cues at retrieval. This was investigated in the present study by exposing participants to a random subset of to-be-recalled items just prior to retrieval (part-set cuing) and then eliciting an overall prediction of memory performance. Across three experiments, participants in part-set cuing conditions recalled proportionally fewer items than did participants who were not exposed to any cues. However, participants were unable to predict the detrimental effect of part-set cues on memory performance in either a semantic (Experiment 1) or an episodic (Experiment 2) memory task. Predictions were better calibrated after practice with part-set cuing, and there was evidence that prior experience with part-set cuing transferred to predictions made for a different part-set cuing task (Experiment 3). This suggests that only under some conditions are participants sensitive to the diminished accessibility of memories wrought by part-set cues and illustrates situations in which participants are or are not aware of variables at retrieval that influence memory performance.     

Response preparation modulates interference from irrelevant spatial information

This study explored the effects of response cues on interference from irrelevant spatial stimulus information (i.e. on the Simon effect). Previous studies, which have always used unreliable response cues, consistently found that valid response cues increase the Simon effect, when compared to a neutral-cue condition. Two experiments tested possible explanations for the effects of response cues on the Simon effect by comparing the effects of unreliable cues to those of reliable cues. The response-speed hypothesis predicts that unreliable and reliable response cues should increase Simon effects, when compared to neutral cues. In contrast, the event-coding hypothesis predicts opposite effects of unreliable and reliable response cues on the Simon effect. Experiment 1 (unreliable cues) replicated previous results: valid cues increased, invalid cues decreased Simon effects. Experiment 2 (reliable cues) showed the opposite results: valid cues decreased Simon effects. The results support the event-coding hypothesis, which assumes that response preparation with unreliable cues and response preparation with reliable cues are qualitatively different.     

Encoding strategies in self-initiated visual working memory

During a typical day, visual working memory (VWM) is recruited to temporarily maintain visual information. Although individuals often memorize external visual information provided to them, on many other occasions they memorize information they have constructed themselves. The latter aspect of memory, which we term self-initiated WM, is prevalent in everyday behavior but has largely been overlooked in the research literature. In the present study we employed a modified change detection task in which participants constructed the displays they memorized, by selecting three or four abstract shapes or real-world objects and placing them at three or four locations in a circular display of eight locations. Half of the trials included identical targets that participants could select. The results demonstrated consistent strategies across participants. To enhance memory performance, participants reported selecting abstract shapes they could verbalize, but they preferred real-world objects with distinct visual features. Furthermore, participants constructed structured memory displays, most frequently based on the Gestalt organization cue of symmetry, and to a lesser extent on cues of proximity and similarity. When identical items were selected, participants mostly placed them in close proximity, demonstrating the construction of configurations based on the interaction between several Gestalt cues. The present results are consistent with recent findings in VWM, showing that memory for visual displays based on Gestalt organization cues can benefit VWM, suggesting that individuals have access to metacognitive knowledge on the benefit of structure in VWM. More generally, this study demonstrates how individuals interact with the world by actively structuring their surroundings to enhance performance.     

People's hypercorrection of high-confidence errors: did they know it all along?

This study investigated the "knew it all along" explanation of the hypercorrection effect. The hypercorrection effect refers to the finding that when people are given corrective feedback, errors that are committed with high confidence are easier to correct than low-confidence errors. Experiment 1 showed that people were more likely to claim that they knew it all along when they were given the answers to high-confidence errors as compared with low-confidence errors. Experiments 2 and 3 investigated whether people really did know the correct answers before being told or whether the claim in Experiment 1 was mere hindsight bias. Experiment 2 showed that (a) participants were more likely to choose the correct answer in a 2nd guess multiple-choice test when they had expressed an error with high rather than low confidence and (b) that they were more likely to generate the correct answers to high-confidence as compared with low-confidence errors after being told they were wrong and to try again. Experiment 3 showed that (c) people were more likely to produce the correct answer when given a 2-letter cue to high- rather than low-confidence errors and that (d) when feedback was scaffolded by presenting the target letters 1 by 1, people needed fewer such letter prompts to reach the correct answers when they had committed high- rather than low-confidence errors. These results converge on the conclusion that when people said that they knew it all along, they were right. This knowledge, no doubt, contributes to why they are able to correct those high-confidence errors so easily.     

Wishful thinking and source monitoring

Memory distortions sometimes serve a purpose: It may be in our interest to misremember some details of an event or to forget others altogether. The present work examines whether a similar phenomenon occurs for source attribution. Given that the source of a memory provides information about the accuracy of its content, people may be biased toward source attributions that are consistent with desired accuracy. In Experiment 1, participants read desirable and undesirable predictions made by sources differing in their a priori reliability and showed a wishful thinking bias--that is, a bias to attribute desirable predictions to the reliable source and undesirable predictions to the unreliable source. Experiment 2 showed that this wishful thinking effect depends on retrieval processes. Experiment 3 showed that under some circumstances, wishes concerning one event can produce systematic source memory errors for others.     

Working memory capacity and strategy use

In this study, we examine the role of strategy use in working memory (WM) tasks by providing short-term memory (STM) task strategy training to participants. In Experiment 1, the participants received four sessions of training to use a story-formation (i.e., chaining) strategy. There were substantial improvements from pretest to posttest (after training) in terms of both STM and WM task performance. Experiment 2 demonstrated that WM task improvement did not occur for control participants, who were given the same amount of practice but were not provided with strategy instructions. An assessment of participants' strategy use on the STM task before training indicated that more strategic participants displayed better WM task performance and better verbal skills. These results support our hypothesis that strategy use influences performance on WM tasks.     

Overriding age differences in attentional capture with top-down processing

Two experiments investigated the influence of top-down information on adult age differences in the ability to search for singleton targets using spatial cues. In Experiment 1, both younger and older adults were equally able to use target-related top-down information (target feature predictability) to avoid attentional capture by uninformative (25% valid) cues. However, during informative (75% valid) cue conditions, older adults demonstrated less efficient use of this cue-related top-down information. The authors extended these findings in Experiment 2 using cues that were either consistent or inconsistent with top-down feature settings. Results from this second experiment showed that although older adults were capable of avoiding attentional capture when provided with top-down information related to target features, capture effects for older adults were notably larger than those of younger adults when only bottom-up information was available. The authors suggest that older adults' ability to use top-down information during search to avoid or attend to cues may be resource-limited.     

Cue usage in memory for location when orientation is fixed

In previous research, it was demonstrated that including one or three cues surrounding a circular field had no effect on spatial memory for dot locations when the field's orientation was fixed, but that there were very large effects when orientation varied across trials (Fitting, Wedell, & Allen, 2007). In four new experiments, we explored the use of external cues in the fixed orientation environment, using 0, 4, 8, or 24 cues and manipulating task difficulty. In Experiments 1-3, the angular bias data supported the use of four quadrant-based prototypes regardless of cue condition, but there were clear cue effects on radial prototype locations. Increasing the number of cues enhanced accuracy of spatial memory for targets closer to cues. In Experiment 4, we severely challenged memory by using multiple targets and a filled delay before estimation. Doing so demonstrated an effect of cues on the categorical structuring of memory. Collectively, findings indicate that when orientation is fixed, cues bolster fine-grain memory, but that they only alter the default categorical scheme when memory demands are high.     

Only pre-cueing but no retro-cueing effects emerge with masked arrow cues

The impact of masked stimulation on cognitive control processes is investigated with much interest. In many cases, masked stimulation suffices to initiate and employ control processes. Shifts of attention either happen in the external environment or internally, for example, in working memory. In the former, even masked cues (i.e., cues that are presented for a period too short to allow strategic use) were shown efficient for shifting attention to particular locations in pre-cue paradigms. Internal attention shifting can be investigated using retro-cues: long after encoding, a valid cue indicates the location to-be-tested via change detection, and this improves performance (retro-cue effect). In the present experiment, participants performed in both a pre- and a retro-cue task with masked and normally presented cues. While the masked cues benefitted performance in the pre-cue task, they did not in the retro-cue task. These results inform about limits of masked stimulation.     

The phenomenology of endogenous orienting

Can we build endogenous expectations about the locus of occurrence of a target without being able to describe them? Participants performed cue-target detection tasks with different proportions of valid and invalid trials, without being informed of these proportions, and demonstrated typical endogenous effects. About half were subsequently able to correctly describe the cue-target relationships ('verbalizers'). However, even non-verbalizer participants showed endogenous orienting with peripheral cues (Experiments 1 and 3), not depending solely on practice (Experiment 2). Explicit instructions did not bring about dramatic advantages in performance (Experiment 4). With central symbolic cues, only verbalizers showed reliable endogenous effects (Experiment 5). We concluded that endogenous orienting with peripheral cues can occur independently of participants developing explicit hypotheses about the cue-target relationships.     

Appearance-based inferences bias source memory

Previous research varying the trustworthiness of appearance has demonstrated that facial characteristics contribute to source memory. Two studies extended this work by investigating the contribution to source memory of babyfaceness, a facial quality known to elicit strong spontaneous trait inferences. Young adult participants viewed younger and older babyfaced and mature-faced individuals paired with sentences that were either congruent or incongruent with the target??s facial characteristics. Identifying a source as dominant or submissive was least accurate when participants chose between a target whose behavior was incongruent with facial characteristics and a lure whose face mismatched the target in appearance but matched the source memory question. In Experiment 1, this effect held true when older sources were identified, but not own-age, younger sources. When task difficulty was increased in Experiment 2, the relationship between face?Cbehavior congruence and lure facial characteristics persisted, but it was not moderated by target age even though participants continued to correctly identify fewer older than younger sources. Taken together, these results indicate that trait expectations associated with variations in facial maturity can bias source memory for both own- and other-age faces, although own-age faces are less vulnerable to this bias, as is shown in the moderation by task difficulty.     

Recognition confidence under violated and confirmed memory expectations

Individuals' memory experiences typically covary with those of others' around them, and on average, an item is more likely to be familiar if a companion recommends it as such. Although it would be ideal if observers could use the external recommendations of others' as statistical priors during recognition decisions, it is currently unclear how or if they do so. Furthermore, understanding the sensitivity of recognition judgments to such external cues is critical for understanding memory conformity and eyewitness suggestibility phenomena. To address this we examined recognition accuracy and confidence following cues from an external source (e.g., "Likely Old") that forecast the likely status of upcoming memory probes. Three regularities emerged. First, hit and correct-rejection rates expectedly fell when participants were invalidly versus validly cued. Second, hit confidence was generally higher than correct-rejection confidence, regardless of cue validity. Finally, and most noteworthy, cue validity interacted with judgment confidence such that validity heavily influenced the confidence of correct rejections but had no discernible influence on the confidence of hits. Bootstrap-informed Monte Carlo simulation supported a dual process recognition model under which familiarity and recollection processes counteract to heavily dampen the influence of external cues on average reported confidence. A 3rd experiment tested this model using source memory. As predicted, because source memory is heavily governed by contextual recollection, cue validity again did not affect confidence, although as with recognition it clearly altered accuracy.     

Surprising feedback improves later memory

The hypercorrection effect is the finding that high-confidence errors are more likely to be corrected after feedback than are low-confidence errors (Butterfield & Metcalfe, 2001). In two experiments, we explored the idea that the hypercorrection effect results from increased attention to surprising feedback. In Experiment 1, participants were more likely to remember the appearance of the presented feedback when the feedback did not match expectations. In Experiment 2, we replicated this effect using more distinctive sources and also demonstrated the hypercorrection effect in this modified paradigm. Overall, participants better remembered both the surface features and the content of surprising feedback.     

Subjective states associated with retrieval failures in Parkinson’s disease

Instances in which we cannot retrieve information immediately but know that the information might be retrieved later are subjective states that accompany retrieval failure. These are expressed in feeling-of-knowing (FOK) and Tip-of-the-tongue (TOT) experiences. In Experiment 1, participants with Parkinson’s disease (PD) and older adult controls were given general questions and asked to report when they experienced a TOT state and to give related information about the missing word. The PD group experienced similar levels of TOTs but provided less correct peripheral information related to the target when in a TOT state. In Experiment 2, participants were given a Semantic (general knowledge questions) and an Episodic (word pairs) FOK task. PD patients failed to accurately predict their future memory performance (FOK) in response to both episodic and semantic cues. Results are interpreted in the context of recent frameworks of memory and metacognition.     

Early Stage Alzheimer's Disease Disrupts Encoding of Contextual Information

Two experiments examined whether impairments in recognition memory in early stage Alzheimer's disease (AD) were due to deficits in encoding contextual information. Normal elderly (NE) and patients diagnosed with mild stage AD learned one of two tasks. In Experiment 1 correct recognition memory required participants to remember not only what items they had experienced on a given trial but also when they had experienced them; Experiment 2 required that participants remember only what they had seen, not when they had seen it. Large recognition memory differences were found between the AD and NE groups in the experiment where time tagging was crucial for successful performance. An error analysis indicated that this was not due to the perseveration of previous learned responses. In Experiment 2, the only requisite for successful recognition was remembering what one had experienced; memory of the temporal record was not necessary for successful performance. In this instance, recognition memory for the NE and AD groups was identical. Taken together these results suggest that memory deficits found in early stage AD are partly due to impaired processing of contextual cues that provide crucial information about when events occur.