A registered report testing the effect of sleep on Deese-Roediger-McDermott false memory: greater lure and veridical recall but fewer intrusions after sleep.

Human memory is known to be supported by sleep. However, less is known about the effect of sleep on false memory, where people incorrectly remember events that never occurred. In the laboratory, false memories are often induced via the Deese-Roediger-McDermott (DRM) paradigm where participants are presented with wordlists comprising semantically related words such as nurse, hospital and sick (studied words). Subsequently, participants are likely to falsely remember that a related lure word such as doctor was presented. Multiple studies have examined whether these false memories are influenced by sleep, with contradictory results. A recent meta-analysis suggests that sleep may increase DRM false memory when short lists are used. We tested this in a registered report (N = 488) with a 2 (Interval: Immediate versus 12 h delay) × 2 (Test Time: 9:00 versus 21:00) between-participant DRM experiment, using short DRM lists (N = 8 words/list) and free recall as the memory test. We found an unexpected time-of-day effect such that completing free recall in the evening led to more intrusions (neither studied nor lure words). Above and beyond this time-of-day effect, the Sleep participants produced fewer intrusions than their Wake counterparts. When this was statistically controlled for, the Sleep participants falsely produced more critical lures. They also correctly recalled more studied words (regardless of intrusions). Exploratory analysis showed that these findings cannot be attributed to differences in output bias, as indexed by the number of total responses. Our overall results cannot be fully captured by existing sleep-specific theories of false memory, but help to define the role of sleep in two more general theories (Fuzzy-Trace and Activation/Monitoring theories) and suggest that sleep may benefit gist abstraction/spreading activation on one hand and memory suppression/source monitoring on the other.

Episodic memory and sleep are involved in the maintenance of context-specific lexical information.

Familiar words come with a wealth of associated knowledge about their variety of usage, accumulated over a lifetime. How do we track and adjust this knowledge as new instances of a word are encountered? A recent study (Cognition) found that, for homonyms (e.g., bank), sleep-associated consolidation facilitates the updating of meaning dominance. Here, we tested the generality of this finding by exposing participants to (Experiment 1; N = 125) nonhomonyms (e.g., bathtub) in sentences that biased their meanings toward a specific interpretation (e.g., bathtub-slip vs. bathtub-relax), and (Experiment 2; N = 128) word-class ambiguous words (e.g., loan) in sentences where the words were used in their dispreferred word class (e.g., "He will loan me money"). Both experiments showed that such sentential experience influenced later interpretation and usage of the words more after a night's sleep than a day awake. We interpret these results as evidence for a general role of episodic memory in language comprehension such that new episodic memories are formed every time a sentence is comprehended, and these memories contribute to lexical processing next time the word is encountered, as well as potentially to the fine-tuning of long-term lexical knowledge. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Word-meaning priming extends beyond homonyms.

When a homonym (e.g., bark) is encountered in a sentential context that biases its interpretation towards a less frequent meaning, subsequent interpretations of the word are more likely to favour that subordinate meaning. Such word-meaning priming effects have been shown to be maintained via sleep-related consolidation, leading some to suggest that declarative memory systems play a crucial role in language comprehension, providing a relatively enduring contextually bound memory trace for the ambiguous word. By this account, word-meaning priming effects should be observable for all words, not just homonyms. In three experiments, participants were exposed to non-homonym targets (e.g., "balloon") in sentences that biased interpretation towards a specific aspect of the word's meaning (e.g., balloon­helium vs. balloon-float). After a ~ 10-30 min delay, the targets were presented in relatedness judgement and associate production tasks to assess whether the sentential contexts enhanced access to the primed aspect of the word's meaning. The results reveal that word-meaning priming effects do extend to non-homonyms. Indeed, there was also some evidence of a more generalised priming that did not rely on prior presentation of the non-homonym itself. We argue that context-specific interpretations of words are maintained during recognition in order to facilitate comprehension over longer periods.

Lexical connectivity effects in immediate serial recall of words.

In six experiments, we tested whether immediate serial recall is influenced by a word's degree centrality, an index of lexical connectivity. Words of high degree centrality are associated with more words in free association norms than those of low degree centrality. Experiment 1 analyzed secondary data to explore the effect of degree centrality in wordlists containing a mixture of high- and low-degree words. High-degree words were advantaged across all serial positions, independently of other variables including word frequency. Experiment 2 replicated this finding using an expanded stimulus set. Experiment 3 used pure lists with each list containing high- or low-degree words only (e.g., HHHHHH vs. LLLLLL). Once again, high-degree words were better recalled across all serial positions. In Experiment 4, each wordlist alternated between high and low-degree words (e.g., HLHLHL and LHLHLH). Recall of low-degree words was facilitated by the neighboring high-degree words, abolishing the overall high-degree advantage. Experiment 5 used a within-participant design and replicated the findings from Experiments 3 and 4 such that the high-degree advantage in pure lists disappeared in alternating lists. Experiment 6 compared high and low frequency words in pure lists while controlling for degree centrality between the item sets. A high-frequency advantage emerged, suggesting that the effects of frequency and degree centrality are separable. We conclude that degree centrality is a distinct psycholinguistic variable that affects serial recall as both (a) an item-level characteristic such that high (vs. low) degree words have greater accessibility in the lexicon and (b) an interitem property such that high-degree words facilitate the recall of neighboring words by enhancing the formation of associative links. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Evidence for preferential attachment: Words that are more well connected in semantic networks are better at acquiring new links in paired-associate learning.

Here, we view the mental lexicon as a semantic network where words are connected if they are semantically related. Steyvers and Tenenbaum (Cognitive Science, 29, 41-78, 2005) proposed that the growth of semantic networks follows preferential attachment, the observation that new nodes are more likely to connect to preexisting nodes that are more well connected (i.e., the rich get richer). If this is the case, well-connected known words should be better at acquiring new links than poorly connected words. We tested this prediction in three paired-associate learning (PAL) experiments in which participants memorized arbitrary cue-response word pairs. We manipulated the semantic connectivity of the cue words, indexed by the words' free associative degree centrality. Experiment 1 is a reanalysis of the PAL data from Qiu and Johns (Psychonomic Bulletin & Review, 27, 114-121, 2020), in which young adults remembered 40 cue-response word pairs (e.g., nature-chain) and completed a cued recall task. Experiment 2 is a preregistered replication of Qiu and Johns. Experiment 3 addressed some limitations in Qiu and Johns's design by using pseudowords as the response items (e.g., boot-arruity). The three experiments converged to show that cue words of higher degree centrality facilitated the recall/recognition of the response items, providing support for the notion that better-connected words have a greater ability to acquire new links (i.e., the rich do get richer). Importantly, while degree centrality consistently accounted for significant portions of variance in PAL accuracy, other psycholinguistic variables (e.g., concreteness, contextual diversity) did not, suggesting that degree centrality is a distinct variable that affects the ease of verbal associative learning.

Why and how the co-occurring familiar object matters in Fast Mapping (FM)? Insights from computational models.

This article uses insights from computational semantic networks to explain why the co-occurring familiar objects are critical to the Fast Mapping (FM) procedure. I first propose that the co-occurring familiar objects provide the novel targets with a 'mimicry opportunity', which may facilitate the establishment of targets in long-term cortical memory networks. I then argue that the occurrence of rapid cortical learning may depend on how 'well-connected' the co-occurring familiar object is in long-term memory networks.