Memory & Cognition最新文献

Sequential behaviour is underpinned by the selection and inhibition of movement at appropriate points in space and time. Sequences embedded among movement patterns must be learnt, yet the contribution of response selection and inhibition to the acquisition of motor sequences remains poorly understood. We addressed this issue by overlaying the serial reaction time task (SRTT) with subliminal masked primes that differentially weighed response tendencies. In Experiment 1, twenty-four healthy young adults, and in Experiment 2, thirty-six participants, performed the SRTT with congruent (same position), incongruent (different position), or neutral (no prime) subliminal masked primes. Each condition featured an embedded eight-digit (Experiment 1) or ten-digit (Experiment 2) second-order sequence, with conditions presented in counterbalanced order during a single session. Sequence specific learning was observed under neutral and congruent prime conditions. Independent of sequence awareness, congruent primes reduced initial response latency and led to greater sequence specific learning compared with neutral primes. However, incongruent primes appeared to attenuate learning (Experiment 1). These results demonstrate that prime congruency modulates sequence specific learning below the threshold of conscious awareness. Congruent primes may elevate the salience of stimulus-response compounds and accentuate learning, but at the cost of increased awareness. Incongruent primes, and the induction of response conflict, attenuate sequence specific learning (Experiment 1) and may prevent the formation of cross-temporal contingencies necessary for implicit motor sequence learning.

While it is well-established that authentic emotional autobiographical memories elicit physiological responses, research suggests that this elicitation can also occur for fabricated autobiographical memories. Yet challenges arise from awareness discrepancies when considering two research fields: Participants in memory studies may be unaware of producing false memories, while liars are aware of fabricating false events. Hence, in two experiments, we compared the psychophysiological pattern of true autobiographical memories with fabricated memory narratives. Using noninvasive biometric devices to measure heart rate (HR) and skin conductance level (SCL), participants were tasked with recalling both true and fabricated negative and neutral autobiographical experiences in a written (Experiment 1) and oral (Experiment 2) way. While in Experiment 1, no statistically significant differences were detected in participants' physiological responses across different recall types, in Experiment 2 we found higher HR responses during the recollection of true negative memories as compared with true neutral and fabricated memory accounts. These latter findings confirm that negative autobiographical memories might be associated with increased HR responses when they are recalled verbally. Furthermore, they suggest that people's awareness of memory authenticity (i.e., recalling true versus fabricated events) may be linked to corresponding physiological reactions linked to specific recollections.

While watching someone kicking a ball, missing moments of ball contact can be incorrectly identified as seen if the event is continued in a causal manner (i.e., the ball flying off). Does event completion also occur for events of a larger scale such as having breakfast (macro-event), which consists of multiple sub-steps like toasting bread (micro-event)? We conducted two experiments to measure event completion in macro-events presenting portions of multiple micro-events. In Experiment 1, video summaries were formed with or without event boundary information where a macro-end was either present or absent. Macro-end signified an overarching goal achievement that signaled the completion of previous tasks (such as leaving the kitchen with a full breakfast plate). More completion occurred for summaries with event boundary information and macro-ends. In Experiment 2, we tested two alternative hypotheses to explore the underlying process by showing the beginnings or ends of a micro-event. While the predictive processing hypothesis suggests that event completion is based more on predicting the future states of the event based on beginning information, the backward inferences hypothesis suggests that event completion relies more on deductions formed after the fact based on event endings. Results of Experiment 2 suggest that the ends of event boundaries lead to more event completion, possibly due to their role in forming causal connectivity. These results help to further understand event completion on a macro level.

The present experiment evaluated the effects of varying intensities of acute exercise on free-recall memory performance while controlling for potential state-dependent effects. Forty-eight young adults completed a within-subject experiment involving seven primary laboratory visits. The encoding and retrieval phases were matched or mismatched by taking place either during rest or during a less than 5-min bout of acute exercise, and at moderate or vigorous intensity. We did not find evidence that the effects of acute exercise on memory were state-dependent but instead demonstrated that memory recall was greater when memory retrieval occurred during vigorous-intensity exercise compared to rest. These findings have important implications for the strategic placement of exercise during the phases of memory (e.g., acquisition, storage, retrieval) to optimize memory performance and suggest boundary conditions of state-dependent learning. We discuss various theoretical accounts (e.g., shift in metabolic resources across brain regions) to explain these findings.

Memory retrieval affects subsequent memory in both positive (e.g., the testing effect) and negative (e.g., retrieval-induced forgetting [RIF]) ways, and can be contrasted with other forms of memory modification (e.g., study-based encoding). Divided attention substantially impairs study-based encoding but has a modest effect on retrieval. What of the subsequent learning consequences of retrieval? Earlier studies indicate that certain positive effects (i.e., the testing effect) are not reduced by distraction, whereas negative effects (i.e., RIF) are eliminated. The present study assessed an indirect (positive) effect of retrieval-the forward testing effect (FTE), in which prior retrieval or retrieval attempts enhance subsequent learning. Two experiments examined the role of attention in both the standard FTE and the pretesting effect. In Experiment 1, participants learned three study lists through retrieval practice or restudy, followed by a fourth study list. Prior retrieval practice enhanced subsequent new learning more than restudy (i.e., the standard FTE), and to a similar degree under full attention (FA) and divided attention (DA). In Experiment 2, participants learned cue-target word pairs by either studying the pair or guessing the target when shown a cue (i.e., pretesting) followed by the correct pair. Pretesting enhanced memory more than just studying to a similar degree under FA and DA. In sum, both forms of the FTE were unaffected by distraction, indicating that these positive consequences of retrieval are not based on controlled processes but instead appear to be relatively obligatory consequences of retrieval (or retrieval attempts). These results also have relevance for specific accounts of the standard FTE and the pretesting effect.

A photo lineup, which consists of one suspect and several physically similar fillers, is often used by the police to test an eyewitness's memory. To optimize memory performance, how similar should the fillers be to the suspect, and how many fillers should be included in the lineup? Recent work suggests that using fillers who match the basic characteristics of the perpetrator (e.g., same age, race, and gender) but who are otherwise maximally dissimilar to the suspect optimizes discriminability. However, the optimal lineup size has been found to vary with filler similarity, with larger lineup sizes increasing or decreasing discriminability depending on whether low-similarity or high-similarity fillers were used, respectively. Because manipulating filler similarity at retrieval affects overall performance, here we investigated whether encoding manipulations that affect overall performance also affect how lineup size influences discriminability. In three experiments, we first replicated prior findings (N = 502), then reduced encoding strength by making study images blurry when low-similarity fillers were used (N = 553), and finally increased encoding strength by repeating study images when high-similarity fillers were used (N = 501). We found that whether overall performance was low or high due these encoding manipulations, discriminability still increased as a function of lineup size when low-similarity fillers were used and decreased as a function of lineup size when high-similarity fillers were used. Thus, lineup size has opposing effects on discriminability when task difficulty is manipulated at retrieval, which narrows the theoretical explanations for why that effect is observed.

The present experiments investigated how interpolated testing and postevent misinformation affected earwitness memory. We examined how the number of tests and when tests occurred affected memory for an overheard event and source monitoring. Across three experiments, participants overheard a crime (i.e., the witnessed event), heard a news report summarizing the crime (postevent information), took a cued-recall test, and lastly, took a source-monitoring test. Experiment 1 compared three groups: repeated cued-recall test, repeated listen, single cued-recall test. Participants in the interpolated test group received a test after the witnessed event and again after the postevent information. Participants in the repeated listen group heard the witnessed event, and immediately relistened to the event before being presented with the postevent information. In Experiment 2 and 3, we varied the retention intervals between the witnessed event and the postevent information in a repeated test context. Our findings suggest that when participants took a test before presentation of the postevent information, they were less accurate on a final cued-recall test of the witnessed event. Importantly, the timing of the first test in relation to the witnessed event and postevent information differentially affected memory for the witnessed event and source monitoring of event and postevent details.

Visuospatial bootstrapping (VSB) refers to the phenomenon in which performance on a verbal working memory task can be enhanced by presenting the verbal material within a familiar visuospatial configuration. This effect is part of a broader literature concerning how working memory is influenced by use of multimodal codes and contributions from long-term memory. The present study aimed to establish whether the VSB effect extends over a brief (5-s) delay period, and to explore the possible mechanisms operating during retention. The VSB effect, as indicated by a verbal recall advantage for digit sequences presented within a familiar visuospatial configuration (modelled on the T-9 keypad) relative to a single-location display, was observed across four experiments. The presence and size of this effect changed with the type of concurrent task activity applied during the delay. Articulatory suppression (Experiment 1) increased the visuospatial display advantage, while spatial tapping (Experiment 2) and a visuospatial judgment task (Experiment 3) both removed it. Finally, manipulation of the attentional demands placed by a verbal task also reduced (but did not abolish) this effect (Experiment 4). This pattern of findings demonstrates how provision of familiar visuospatial information at encoding can continue to support verbal working memory over time, with varying demands on modality-specific and general processing resources.

The present study investigated the effects of long-term knowledge on backward masking interference in visual working memory (VWM) by varying the similarity of mask stimuli along categorical dimensions. To-be-remembered items and masks were taken from categories controlled for perceptual distinctiveness and distinctiveness in kinds (e.g., there are many kinds of cars and few kinds of coffee mugs). Participants completed a change-detection task in which the memory array consisted of exemplars from either a similar or distinctive category, followed by a mask array of items from the same category (conceptually similar versus conceptually distinct categories), a different category, or no mask. The results over two experiments showed greater interference from conceptually similar masks as compared with the other conditions across stimulus onset asynchrony (SOA) conditions, suggesting masking with conceptually similar categories leads to more interference even when masks are shown well after the stimulus. These results have important implications for both the nature and time course of long-term conceptual knowledge influencing VWM, particularly when using complex real-world objects.

Processing that occurs while information is held in working memory is critical in long-term retention of that information. One counterintuitive finding is that the concurrent processing required during complex span tasks typically impairs immediate memory, while also leading to improved delayed memory. One proposed mechanism for this effect is retrieval practice that occurs each time memory items are displaced to allow for concurrent processing during complex span tasks. Other research has instead suggested that increased free time during complex span procedures underlies this effect. In the present study, we presented participants with memory items in simple, complex, and slow span tasks and compared their performance on immediate and delayed memory tests. We found that how much a participant engaged with the secondary task of the complex span task corresponded with how strongly they exhibited a complex span boost on delayed memory performance. We also probed what participants were thinking about during the task, and found that participants' focus varied depending both on task type and secondary task engagement. The results support repeated retrieval as a key mechanism in the relationship between working memory processing and long-term retention. Further, the present study highlights the importance of variation in individual cognitive processing in predicting long-term outcomes even when objective conditions remain unchanged.