Memory & Cognition最新文献

Working memory (WM) often includes heterogenous items, as when one uses it while assembling a desk from sets of boards, knobs, bolts, and washers. Here, we investigate how WM capacity is limited when recalling multiple sets of items, for which performance surpasses the usual limits observed in single-set procedures. We presented participants (N = 181) with up to four sets of items for serial recall, usually of different stimulus types in the same trial (colors, characters, locations, and/or shapes). Conditions differed in the total number of items, the number of sets, and/or item types across sets in a trial. For uniformity in analyses, Set 1 was kept constant at three items of a type and was usually recalled first, free of output interference. In Experiment 1, recall of Set 1 was not only limited by the total number of items but also by the number of sets in a trial. Experiment 2 ruled out interference as an alternative explanation. Experiments 3-4 showed the dependency of the results on clearly grouped presentation of the sets. The results suggest that groups of items are associated as newly formed, often incomplete chunks offloaded from the focus of attention (FoA) to an activated portion of long-term memory (aLTM) for later retrieval. This offloading process would spare capacity but not without cost; a fraction of an item was lost from Set 1 for each subsequent item recalled. We present a dual-stage theory in which pointers held in the capacity-limited FoA allow retrieval of chunks from aLTM.

Studies suggested that learners can use both prosodic and distributional information for word segmentation. Interestingly, recent work on statistical word segmentation has suggested rhythm perception plays a significant role. This is because syllable sequences used to study statistical word segmentation are generated by concatenating uniform-length words, which generate a rhythm percept that is consistent with the word boundaries. In this study, we manipulate high-order constraints on how words are concatenated together, such as whether a word can immediately follow itself, and examine its effect on learning. In addition, we ask participants to rate differently constructed test items, so we can model their behavior computationally. We find that learning was comparable regardless of whether the input sequence contains immediate repetition. Moreover, the ratings of different test items are inconsistent with predictions from second-order statistics. We provide a unified theoretical framework to understand these results, where our model generates predictions on how syllable sequences are segmented and represented. The rhythm model predicts that the higher-order organization of the words does not influence learning as long as the features leading to rhythm perception are preserved. Moreover, we can leverage the outputs of the rhythm model to show that first-order statistics can explain results well, better in fact than second-order statistics. These results reassert the theoretical centrality of first-order statistics, such as pairwise counts and positional counts, which have traditionally been shown to influence artificial language learning.

Acute vigorous-intensity exercise has been shown to positively impact cognitive function, including long-term episodic memory performance. However, few studies have investigated whether individual differences in baseline memory influence the relationship between acute exercise and memory performance. Thus, the purpose of this experiment was to evaluate baseline episodic memory as a potential moderator of the relationship between acute exercise and memory. 213 young adults completed a within-subjects, counterbalanced design. Participants completed two conditions: a 20-min vigorous-intensity exercise condition and a non-exercise control condition. For each condition, two list-learning memory assessments were employed, one conducted after a 20-min delay and another after a 24-h delay. Baseline long-term episodic memory was evaluated from the control condition using participants' episodic memory performance at the 24-h delay. We found that baseline episodic memory moderated the relationship between acute exercise and memory performance: participants with lower baseline episodic memory ability showed the greatest increases in long-term episodic memory performance following a 20-min vigorous-intensity exercise. These results suggest that individual differences in memory performance should be considered as an important moderator when evaluating the relationship between acute exercise and long-term episodic memory function.

The structure of events in which information has been learned can meaningfully impact memory, particularly for information that is encountered near an event boundary. Prior work has shown that separating a list of words into multiple events can improve later memory, suggesting that event structure could be leveraged for a benefit. That is, using event structure can help chunk a large set of information into more manageable units. Our aim was to replicate a prior finding that dividing a list of words to be learned in two rooms would improve later performance. Our results revealed that across two experiments, there was little evidence that memory was better when words were learned across two rooms rather than one. This did occur in one experiment, but only for words around the event boundary. However, this effect quickly dissipated after a short post-learning delay when a person moved through other rooms prior to testing.

To what extent does pretesting - the learning technique of guessing to-be-learned content before studying the correct answers - enhance factual knowledge, and does its effectiveness depend on which part of a fact is pretested? We investigated memory for different parts of facts when pretesting involved either the subject (e.g., "_____ is the goddess of agriculture") or a key term from the predicative (e.g., "Demeter is the goddess of _____"), compared to studying intact facts. Experiments 1a-4 revealed asymmetrical learning patterns: Pretesting on the subject enhanced memory for the predicative key term, but not consistently for the subject itself, whereas pretesting on the predicative key term, at best, enhanced memory for that key term but not for the subject. When word frequency among subject and predicative terms were closely matched in Experiments 5-7, however, pretesting yielded highly symmetrical learning - enhancing memory for both terms regardless of which one was pretested. That enhancement occurred despite differences in associative strength and semantic structure, whereas syntactic and other structural influences, including extra cue words, were ruled out. Together, these findings reveal that pretesting can improve memory for both tested and untested fact terms, with lexical properties exerting strong influences on the scope and magnitude of improvement. The effects of pretesting on facts therefore depend on how easily learners can access and encode fact elements, and accordingly, which terms to pretest should be considered carefully when using pretesting for fact learning.

The shift of attention from external stimuli toward task-unrelated thoughts (TUTs), or mind-wandering, has been shown to disrupt encoding and subsequent retrieval of information. The present study examined how TUT during encoding affects memory for visual scenes that vary in memorability, an intrinsic stimulus property reflecting the likelihood of recognition across individuals. In Experiment 1, participants studied images of high or low memorability while intermittently reporting their attentional state. A subsequent recognition test revealed independent effects of mind-wandering and memorability on memory performance: TUT during encoding was associated with lower recognition accuracy and high memorability images were better recognized than low memorability images, but there were no interactions. In Experiment 2, we extended this paradigm to free recall using a novel drawing-based methodology. Participants studied and later drew scenes from memory, with recall quantified as the proportion of objects drawn relative to a perception baseline. The results showed that TUT impaired free recall while memorability enhanced free recall. Further evidence suggested that memorability only conferred a benefit to free recall when images were encoded during an on-task state. These findings indicate that both attentional state and image memorability are positively associated with recognition and recall. Although these two factors independently impact recognition, there is some indication that they may interact for recall, suggesting a need for focused attention to harness the mnemonic benefits of highly memorable stimuli.

The Attentional Boost Effect (ABE) refers to the enhancement in memory for background information that co-occurs with the detection of a target in a detection task. Previous research suggests that this effect is modulated by item distinctiveness, meaning that when background items have high distinctiveness (e.g., low-frequency words, negative items), the ABE is significantly reduced or even disappears. However, in previous studies, the detection stimulus and background items were synchronized in their onset times, which could lead to maximal overlap between the two enhancement effects. Accordingly, to further understand the relationship between item distinctiveness and target detection, we manipulated distinctive and nondistinctive memory items in three experiments and manipulated the onset time of detections stimuli. Distinctiveness was varied by manipulating the word frequency (Experiment 1), and the emotional valence of both words (Experiment 2) and images (Experiment 3). The detection stimulus was presented within two time windows: 0-100 ms or 400-500 ms during the presentation of background items. The results indicated that, compared with word frequency, negative valence exerted a more pronounced modulation of the ABE, and this modulation was not influenced by the onset time of detection stimulus. This finding further deepens our understanding of the interaction between item distinctiveness and the ABE, suggesting a complex competitive relationship between the two effects.

Research has shown that the activation of semantic memories leads to the activation of autobiographical memories. Known as semantic-to-autobiographical memory priming, it has been argued that this form of priming reflects the functional role that autobiographical memory has in semantic processing. It has also been argued that if this proposition is true, one should see the reverse form of priming, autobiographical-to-semantic memory priming. We tested this hypothesis in the current study by examining the priming effects of autobiographical memory retrieval on two conceptual priming tasks, category exemplar generation and word association. In two experiments, participants recalled autobiographical memories in response to cue words (e.g., beach, cat, strawberry, etc.), and they were subsequently given a category exemplar-generation task (Experiment 1) or a word-association task (Experiment 2). The results of both experiments showed that autobiographical memory retrieval led to significant priming on the conceptual tasks (relative to control conditions), and priming following autobiographical memory retrieval was as strong as priming following semantic processing (i.e., word familiarity judgments). The results support the notion of autobiographical-to-semantic memory priming, and taken with the results of semantic-to-autobiographical memory priming observed in other studies, they also show that priming between autobiographical memory and semantic memory is bidirectional. The results also support the idea that autobiographical memories have a functional role in semantic processing.

Natural language is often depicted as the sine qua non of mathematical thinking, a view buttressed by findings of language-of-training effects among bilinguals. These findings, however, have been limited to studies of arithmetic. Here, we asked whether algebraic thinking differs. We trained Chinese-English bilinguals and English monolinguals to solve arithmetic and algebra problems in either Chinese or English and tested them on new and old problems in both languages. In Experiments 1 and 2, bilinguals solved arithmetic problems faster in their trained than untrained language, and old arithmetic problems were solved faster than new ones. However, both the language-of-training and novelty effect were reduced or eliminated when learning algebraic rules. Strikingly, when English monolinguals were given Chinese problems, they successfully learned to solve the algebraic-but not arithmetic-problems. Together, the findings suggest that-unlike rote arithmetic-algebraic rules need not be encoded in natural language.

Assessing the use of proactive cognitive control is essential for understanding how thoughts and actions are regulated. The present study aimed to determine whether proactive control can be measured through patterns of eye movements during the cue-probe delay in a spatially modified AX-CPT. Across two experiments, we found that gaze activity at screen locations where cues and probes appeared predicted both the extent of proactive control adopted by participants and their ability to override a prepotent response tendency. However, the specific cognitive processes underlying the engagement of proactive control varied depending on task demands. Specifically, when the cue-probe delay was relatively short (Experiment 1), proactive control was characterized by rapid shifts in visual attention to support cognitive demands associated with frequent changes in the location of probe stimuli. In contrast, when the cue-probe delay was extended (Experiment 2), proactive control aligned with traditional conceptualizations, relying more on increased cue maintenance. Together, these results demonstrate that eye-movement patterns may serve as the foundation for ocular-based measures of proactive control, enabling further investigation into factors influencing its engagement and potential individual differences in its use. Implications that the results have for theories of controlled processing and inhibitory control are discussed.