Paired-associate versus cross-situational: How do verbal working memory and word familiarity affect word learning?

Word learning is one of the first steps into language, and vocabulary knowledge predicts reading, speaking, and writing ability. There are several pathways to word learning and little is known about how they differ. Previous research has investigated paired-associate (PAL) and cross-situational word learning (CSWL) separately, limiting the understanding of how the learning process compares across the two. In PAL, the roles of word familiarity and working memory have been thoroughly examined, but these same factors have received very little attention in CSWL. We randomly assigned 126 monolingual adults to PAL or CSWL. In each task, names of 12 novel objects were learned (six familiar words, six unfamiliar words). Logistic mixed-effects models examined whether word-learning paradigm, word type and working memory (measured with a backward digit-span task) predicted learning. Results suggest better learning performance in PAL and on familiar words. Working memory predicted word learning across paradigms, but no interactions were found between any of the predictors. This suggests that PAL is easier than CSWL, likely because of reduced ambiguity between the word and the referent, but that learning across both paradigms is equally enhanced by word familiarity, and similarly supported by working memory.

Asymmetric Weights and Retrieval Practice in an Autoassociative Neural Network Model of Paired-Associate Learning.

Rizzuto and Kahana (2001) applied an autoassociative Hopfield network to a paired-associate word learning experiment in which (1) participants studied word pairs (e.g., ABSENCE-HOLLOW), (2) were tested in one direction (ABSENCE-?) on a first test, and (3) were tested in the same direction again or in the reverse direction (?-HOLLOW) on a second test. The model contained a correlation parameter to capture the dependence between forward versus backward learning between the two words of a word pair, revealing correlation values close to 1.0 for all participants, consistent with neural network models that use the same weight for communication in both directions between nodes. We addressed several limitations of the model simulations and proposed two new models incorporating retrieval practice learning (e.g., the effect of the first test on the second) that fit the accuracy data more effectively, revealing substantially lower correlation values (average of .45 across participants, with zero correlation for some participants). In addition, we analyzed recall latencies, finding that second test recall was faster in the same direction after a correct first test. Only a model with stochastic retrieval practice learning predicted this effect. In conclusion, recall accuracy and recall latency suggest asymmetric learning, particularly in light of retrieval practice effects.

The deceptive nature of associative word pairs: the effects of associative direction on judgments of learning.

The accuracy of judgments of learning (JOLs) in forecasting later recall of cue-target pairs is sensitive to associative direction. JOLs are generally well calibrated for forward associative pairs (e.g., credit-card), but recall accuracy is often overestimated for backward pairs (e.g., card-credit). The present study further examines the effect of associative direction on JOL accuracy by comparing forward and backward pairs to unrelated pairs and symmetrical associates (e.g., salt-pepper)-a novel comparison. The correspondence between initial JOLs and recall accuracy was examined when study was either self-paced with concurrent JOLs (Experiment 1), when study/JOL duration was equated across pair types (Experiment 2), when JOLs were made immediately following study (Experiment 3), and when JOLs were made after a delay (Experiment 4). Across experiments, JOLs accurately estimated correct recall for forward pairs, but overestimated recall for symmetrical, backward, and unrelated pairs-an overestimation that was particularly robust for backward pairs. Calibration plots depicting JOL ratings against their corresponding recall accuracy indicated overestimations occurred for all pair types, though overestimations only occurred at high JOL ratings for symmetrical and forward pairs, a qualitative difference that was not captured in standard analyses of mean JOL and recall rates.

Postretrieval Relearning Strengthens Hippocampal Memories via Destabilization and Reconsolidation.

Memory reconsolidation is hypothesized to be a mechanism by which memories can be updated with new information. Such updating has previously been shown to weaken memory expression or change the nature of the memory. Here we demonstrate that retrieval-induced memory destabilization also allows that memory to be strengthened by additional learning. We show that for rodent contextual fear memories, this retrieval conditioning effect is observed only when conditioning occurs within a specific temporal window opened by retrieval. Moreover, it necessitates hippocampal protein degradation at the proteasome and engages hippocampal Zif268 protein expression, both of which are established mechanisms of memory destabilization-reconsolidation. We also demonstrate a conceptually analogous pattern of results in human visual paired-associate learning. Retrieval-relearning strengthens memory performance, again only when relearning occurs within the temporal window of memory reconsolidation. These findings link retrieval-mediated learning in humans to the reconsolidation literature, and have potential implications both for the understanding of endogenous memory gains and strategies to boost weakly learned memories.SIGNIFICANCE STATEMENT Memory reconsolidation allows existing memories to be updated with new information. Previous research has demonstrated that reconsolidation can be manipulated pharmacologically and behaviorally to impair problematic memories. In this article, we show that reconsolidation can also be exploited to strengthen memory. This is shown both in rats, in a fear memory setting, and in a human declarative memory setting. For both, the behavioral conditions necessary to observe the memory strengthening match those that are required to trigger memory reconsolidation. There are several behavioral approaches that have previously been shown convincingly to strengthen memory. The present demonstration that reconsolidation can underpin long-lasting memory improvements may both provide an underlying mechanism for such approaches and provide new strategies to boost memories.

A Geometric Characterization of Population Coding in the Prefrontal Cortex and Hippocampus during a Paired-Associate Learning Task.

Large-scale neuronal recording techniques have enabled discoveries of population-level mechanisms for neural computation. However, it is not clear how these mechanisms form by trial-and-error learning. In this article, we present an initial effort to characterize the population activity in monkey prefrontal cortex (PFC) and hippocampus (HPC) during the learning phase of a paired-associate task. To analyze the population data, we introduce the normalized distance, a dimensionless metric that describes the encoding of cognitive variables from the geometrical relationship among neural trajectories in state space. It is found that PFC exhibits a more sustained encoding of the visual stimuli, whereas HPC only transiently encodes the identity of the associate stimuli. Surprisingly, after learning, the neural activity is not reorganized to reflect the task structure, raising the possibility that learning is accompanied by some "silent" mechanism that does not explicitly change the neural representations. We did find partial evidence on the learning-dependent changes for some of the task variables. This study shows the feasibility of using normalized distance as a metric to characterize and compare population-level encoding of task variables and suggests further directions to explore learning-dependent changes in the neural circuits.

Novel word learning deficits in infants at family risk for dyslexia.

Children of reading age diagnosed with dyslexia show deficits in reading and spelling skills, but early markers of later dyslexia are already present in infancy in auditory processing and phonological domains. Deficits in lexical development are not typically associated with dyslexia. Nevertheless, it is possible that early auditory/phonological deficits would have detrimental effects on the encoding and storage of novel lexical items. Word-learning difficulties have been demonstrated in school-aged dyslexic children using paired associate learning tasks, but earlier manifestations in infants who are at family risk for dyslexia have not been investigated. This study assessed novel word learning in 19-month-old infants at risk for dyslexia (by virtue of having one dyslexic parent) and infants not at risk for any developmental disorder. Infants completed a word-learning task that required them to map two novel words to their corresponding novel referents. Not at-risk infants showed increased looking time to the novel referents at test compared with at-risk infants. These findings demonstrate, for the first time, that at-risk infants show differences in novel word-learning (fast-mapping) tasks compared with not at-risk infants. Our findings have implications for the development and consolidation of early lexical and phonological skills in infants at family risk of later dyslexia.

Paired-associate learning, animacy, and imageability effects in the survival advantage.

The current study examined animacy and paired-associate learning through a survival-processing paradigm (Nairne et al. in Journal of Experimental Psychology: Learning, Memory, and Cognition, 33(2), 263-273, 2007; Schwartz & Brothers, 2014). English-speaking monolingual participants were asked to learn a set of new word translations to improve their chances of survival or to improve their study abroad experience. Animate and inanimate words were included in this task, to further examine animacy effects in cued recall paradigms (Popp & Serra in Journal of Experimental Psychology: Learning, Memory, and Cognition, 42(2), 186-201, 2016; VanArsdall et al. in Experimental Psychology, 60(3), 172-178, 2013). Across sentence-completion, matching, and picture-naming tasks, learning was facilitated by the survival context, relative to the study abroad context and an intentional learning condition. Scenario ratings indicated this survival advantage could also be a function of higher imageability ratings for the survival context than for the study abroad context. Replicating previous findings with cued recall, inanimate words were overall better remembered than animate words, across all three tasks, though survival processing facilitated language-learning for both animate and inanimate categories. This 'reverse animacy effect' replicated previous findings by Popp and Serra (Journal of Experimental Psychology: Learning, Memory, and Cognition, 42(2), 186-201, 2016), showing animate words can interfere with a participant's ability to create associations with their words, including those in a new language. These results are discussed with regards to the widely-reliable survival and animacy advantages, with a particular emphasis on the role of imageability in this paradigm.

Normative data for Chinese-English paired associates.

Paired-associate learning is one of the most commonly used paradigms to study human memory. In many of these studies, participants are typically told to learn foreign language-English translations, such as Swahili-English or Lithuanian-English pairs. One limitation of these currently available foreign language-English translation norms is that their foreign languages are based on the alphabetic writing system, thereby preventing researchers from generalizing their findings to languages based on logographic writing systems. In the present study we collected normative data for 160 Chinese-English word pairs. Participants completed three study-test cycles, followed by metacognitive judgments on their learning experience. For each pair, we report recall performance, recall latency, ease of learning, and judgments of learning. A simultaneous multiple regression analysis with frequency (of both the English word and the Chinese character), word length (English), and number of strokes (Chinese) as predictors revealed that a greater number of strokes (or higher visual complexity) for the Chinese characters predicted lower target recall.

Exploring factors underlying children's acquisition and retrieval of sound-symbol association skills.

Letter knowledge is considered an important cognitive foundation for learning to read. The underlying mechanisms of the association between letter knowledge and reading skills are, however, not fully understood. Acquiring letter knowledge depends on the ability to learn and retrieve sound-symbol pairings. In the current study, this process was explored by setting preschool children's (N = 242, mean age = 5.57 years) performance in the acquisition and retrieval of a paired associate learning (PAL) task in relation to their letter knowledge as well as to their performance in tasks assessing precursors of reading skills (i.e., phonological awareness, rapid automatized naming, phonological short-term memory, backward recall, and response inhibition). Multiple regression analyses revealed that performance in the acquisition of the PAL task was significantly associated with phonological awareness and backward recall, whereas performance in the retrieval of the PAL task was significantly associated with rapid automatized naming, phonological awareness, and backward recall. Moreover, PAL proved to be mediating the relation between reading precursors and letter knowledge. Together, these findings indicate that the acquisition of letter knowledge may depend on a visual-verbal associative learning mechanism and that different factors contribute to the acquisition and retrieval of such visual-verbal associations.

Adding the keyword mnemonic to retrieval practice: A potent combination for foreign language vocabulary learning?

The keyword mnemonic and retrieval practice are two cognitive techniques that have each been identified to enhance foreign language vocabulary learning. However, little is known about the use of these techniques in combination. Previous demonstrations of retrieval-practice effects in foreign language vocabulary learning have tended to use several rounds of retrieval practice. In contrast, we focused on a situation in which retrieval practice was limited to twice per item. For this situation, it is unclear whether retrieval practice will be effective relative to restudying. We advance the view that the keyword mnemonic catalyzes the effectiveness of retrieval practice in this learning context. Experiment 1 (48-h delay) partially supported this view, such that there was no testing effect with retrieval practice alone, but the keyword-retrieval combination did not promote better retention than keyword alone. Experiments 2 and 3 (1-week delay) supported the catalytic view by showing that the keyword-retrieval combination was better than keyword alone, but in the absence of keyword encoding there was no retrieval practice effect (replicating Experiment 1). However, with four rounds of retrieval practice, a marginally significant testing effect emerged (Experiment 3). Moreover, the routes through which participants reached each answer were identified by asking retrieval-route questions in Experiments 2 and 3. Keyword-mediated retrieval, which was observed sometimes even in no-keyword instructed conditions, was shown to be more effective than unmediated retrieval. Our findings suggest that incorporating effective encoding techniques prior to retrieval practice could augment the effectiveness of retrieval practice, at least for vocabulary learning.

Scopolamine does not impact declarative and motor memory consolidation across a night of sleep or a day of wakefulness.

It has been proposed that normal waking levels of acetylcholine (ACH) are important for initial memory acquisition, and that decreased ACH is critical for memory consolidation. Sleep is thought to benefit memory consolidation in part due to the predominance of low ACH levels observed during non-rapid eye movement sleep. Here we examined whether sleep and ACH suppression with the cholinergic antagonist scopolamine impact declarative and motor memory consolidation across a night of sleep or a day of wakefulness. Eighty-seven participants trained on a declarative and motor memory task in the morning or evening. Following training, participants were administered a scopolamine (0.4 mg) or placebo capsule. Participants were retested on the tasks 12 h later after a day of wake or a night of sleep. Reducing ACH levels with scopolamine provided no consolidation benefit for either task. Additionally, we found that sleep had a pronounced beneficial effect for declarative, but not motor memory consolidation. Lastly, in an exploratory analysis of the relationship between motivation and memory performance, we found that indices of intrinsic motivation were associated with improved memory acquisition and consolidation. Our findings show that reducing ACH levels after memory acquisition has no impact on the consolidation of declarative or motor memories. Additionally, sleep benefitted declarative memory but not motor memory consolidation, which highlights the interesting, though uncommon, finding that performance on some tasks might not benefit from sleep. Interestingly, the future study of intrinsic motivation may be warranted given its relationship to memory acquisition and consolidation. These findings add to our understanding of how sleep and acetylcholine impact memory consolidation, and may provide some insight about the role of ACH in memory disorders such as Alzheimer's disease.

Resilient and depressive-like rats show distinct cognitive impairments in the touchscreen paired-associates learning (PAL) task.

Depression-associated cognitive impairments persist after remission from affective symptoms of major depressive disorder (MDD), decreasing quality of life and increasing risk of relapse in patients. Conventional antidepressants are ineffective in restoring cognitive functions. Therefore, novel antidepressants with improved efficacy for ameliorating cognitive symptoms are required. For tailoring such antidepressants, translational animal models are in demand. The chronic mild stress (CMS) model is a well-validated preclinical model of depression and known for eliciting the MDD core symptom "anhedonia" in stress-susceptible rats. Thus, cognitive performance was assessed in rats susceptible (depressive-like) or resilient to CMS and in unchallenged controls. The rodent analogue of the human touchscreen Paired-Associates Learning (PAL) task was used for cognitive assessment. Both stress groups exhibited a lack of response inhibition compared to controls while only the depressive-like group was impaired in task acquisition. The results indicate that cognitive deficits specifically associate with the anhedonic-like state rather than being a general consequence of stress exposure. Hence, we propose that the application of a translational touchscreen task on the etiologically valid CMS model, displaying depression-associated cognitive impairments, provides a novel platform for pro-cognitive and clinically pertinent antidepressant drug screening.

Verbal task demands are key in explaining the relationship between paired-associate learning and reading ability.

Paired-associate learning (PAL) tasks measure the ability to form a novel association between a stimulus and a response. Performance on such tasks is strongly associated with reading ability, and there is increasing evidence that verbal task demands may be critical in explaining this relationship. The current study investigated the relationships between different forms of PAL and reading ability. A total of 97 children aged 8-10 years completed a battery of reading assessments and six different PAL tasks (phoneme-phoneme, visual-phoneme, nonverbal-nonverbal, visual-nonverbal, nonword-nonword, and visual-nonword) involving both familiar phonemes and unfamiliar nonwords. A latent variable path model showed that PAL ability is captured by two correlated latent variables: auditory-articulatory and visual-articulatory. The auditory-articulatory latent variable was the stronger predictor of reading ability, providing support for a verbal account of the PAL-reading relationship.

The short- and long-term predictions of reading accuracy and speed from paired-associate learning.

Cross-sectional studies have established that performance on paired-associate learning (PAL) tasks is associated with reading performance. There are good reasons to expect such a relationship because learning to read involves learning the sounds of individual letters and possibly also sounds of strings of letters (e.g., spelling patterns). However, results from longitudinal studies have been mixed. A closer look at these studies suggests that PAL may be related to development of accuracy rather than speed in reading. This suggestion was investigated directly in the current longitudinal study. The study followed 137 students from Grade 0 (kindergarten) to Grade 5. In Grade 0, they completed measures of PAL, letter knowledge, phoneme awareness, and rapid automatized naming (RAN). In Grades 1 and 5, decoding accuracy was measured with the addition of decoding speed in Grade 5. PAL in Grade 0 was found to be a unique predictor of decoding accuracy in Grades 1 and 5 after controlling for Grade 0 letter knowledge, phoneme awareness, and RAN. PAL in Grade 0 even contributed to Grade 5 decoding accuracy after also controlling for Grade 1 decoding. Zero-order correlations between PAL and Grade 5 decoding speed were nonsignificant and close to zero. The results indicate that PAL measures a trait that may influence reading development over a substantial amount of time. Possible roles of PAL in decoding development over time are discussed, for example, how verbal learning may be a core component in the acquisition of associations between letter patterns (spelling patterns) and their pronunciation.

When people's judgments of learning (JOLs) are extremely accurate at predicting subsequent recall: the "Displaced-JOL effect".

Judgments of learning (JOL) made after a delay more accurately predict subsequent recall than JOLs made immediately after learning. One explanation is that delayed JOLs involve retrieving information about the target item from secondary memory, whereas immediate JOLs involve retrieval from primary memory. One view of working memory claims that information in primary memory is displaced to secondary memory when attention is shifted to a secondary task. Thus, immediate JOLs might be as accurate as delayed JOLs if an intervening task displaces the target item from primary memory, requiring retrieval from secondary memory, prior to making the JOL. In four experiments, participants saw related word-pairs and made JOLs predicting later recall of the item. In Experiment 1, delayed JOLs were more accurate than JOLs made shortly after learning, regardless of whether a secondary task intervened between learning and JOL. In Experiments 2-4, the secondary task demands increased and JOLs made shortly after learning with an intervening task were just as accurate as delayed JOLs, and both were more accurate than immediate JOLs with no intervening task (Experiment 4). These results are consistent with a retrieval-based account of JOLs, and demonstrate that the "delayed-JOL effect" can be obtained without a long delay.

Examining the direct and indirect effects of visual-verbal paired associate learning on Chinese word reading.

Associative learning, traditionally measured with paired associate learning (PAL) tasks, has been found to predict reading ability in several languages. However, it remains unclear whether it also predicts word reading in Chinese, which is known for its ambiguous print-sound correspondences, and whether its effects are direct or indirect through the effects of other reading-related skills such as phonological awareness and rapid naming. Thus, the purpose of this study was to examine the direct and indirect effects of visual-verbal PAL on word reading in an unselected sample of Chinese children followed from the second to the third kindergarten year. A sample of 141 second-year kindergarten children (71 girls and 70 boys; mean age=58.99months, SD=3.17) were followed for a year and were assessed at both times on measures of visual-verbal PAL, rapid naming, and phonological awareness. In the third kindergarten year, they were also assessed on word reading. The results of path analysis showed that visual-verbal PAL exerted a significant direct effect on word reading that was independent of the effects of phonological awareness and rapid naming. However, it also exerted significant indirect effects through phonological awareness. Taken together, these findings suggest that variations in cross-modal associative learning (as measured by visual-verbal PAL) place constraints on the development of word recognition skills irrespective of the characteristics of the orthography children are learning to read.

Stimulant drug effects on touchscreen automated paired-associates learning (PAL) in rats.

Here we tested in rats effects of the procognitive drugs modafinil and methylphenidate on post-acquisition performance in an object-location paired-associates learning (PAL) task. Modafinil (32; 64 mg/kg) was without effect, while higher (9 mg/kg) but not lower (4.5 mg/kg) doses of methylphenidate impaired PAL performance. Likewise, higher but not lower doses of amphetamine (0.4; 0.8 mg/kg) and MK-801 (0.08; 0.12 mg/kg) decreased PAL performance. Impaired PAL performance induced by methylphenidate, amphetamine, and MK801 most likely reflects compromised cognitive function, e.g., retrieval of learned paired associates. Our data suggest that stimulant drugs such as methylphenidate and modafinil might not facilitate performance in hippocampus-related cognitive tasks.

Recall and response time norms for English-Swahili word pairs and facts about Kenya.

In the vast literature exploring learning, many studies have used paired-associate stimuli, despite the fact that real-world learning involves many different types of information. One of the most popular materials used in studies of learning has been a set of Swahili-English word pairs for which Nelson and Dunlosky (Memory 2; 325-335, 1994) published recall norms two decades ago. These norms involved use of the Swahili words as cues to facilitate recall of the English translation. It is unclear whether cueing in the opposite direction (from English to Swahili) would lead to symmetric recall performance. Bilingual research has suggested that translation in these two different directions involves asymmetric links that may differentially impact recall performance, depending on which language is used as the cue (Kroll & Stewart, Journal of Memory and Language 33; 149-174,1994). Moreover, the norms for these and many other learning stimuli have typically been gathered from college students. In the present study, we report recall accuracy and response time norms for Swahili words when they are cued by their English translations. We also report norms for a companion set of fact stimuli that may be used along with the Swahili-English word pairs to assess learning on a broader scale across different stimulus materials. Data were collected using Amazon's Mechanical Turk to establish a sample that was diverse in both age and ethnicity. These different, but related, stimulus sets will be applicable to studies of learning, metacognition, and memory in diverse samples.

The linguistic and cognitive factors associated with lexical-gustatory synesthesia: A case study.

Past research on lexical-gustatory synesthesia (people who associate words with tastes) has shown that linguistic factors underlie the inducer (word)-concurrent (taste) mappings in these individuals. The developmental cognitive model envisioned by Simner and Haywood (2009), and an extension of it proposed in this paper can be used to understand these linguistic associations. The first aim of the current case study was to test these models by examining the linguistic factors associated with this type of synesthesia. The influence of lexical-gustatory synesthesia on memory was investigated using a paired-associate learning task. Further, the present case study also examined if word-pairs with same or similar tastes and word-pairs with dissimilar tastes enhanced learning relative to word pairs that had no tastes. As predicted, the findings revealed possible phonological, phonological-lexical, and lexical-semantic factors linking the inducer-concurrent pairings. These findings are in line with the developmental cognitive models of LG synesthesia. There were no effects of synesthesia on memory as demonstrated by the lack of any significant difference between the synesthete and non-synesthete controls on a paired-associate learning task. Moreover, no significant differences emerged between the "no taste" and "taste" conditions (although she performed slightly better on the "no taste" condition). Interestingly, a metamemory task (judgment-of-learning) revealed the opposite. That is, the synesthete predicted that her learning would be better in the "taste" condition when compared to the "no taste" condition. This indicates that the word-pairs, which produced tastes, could have created a "foresight bias". This is attributed to the unidirectional nature of this individual's LG synesthesia. This finding should, however, be treated with caution because it is a preliminary finding based on a single subject and needs to be corroborated with future studies on other lexical-gustatory synesthetes.

Novel Word Learning, Reading Difficulties, and Phonological Processing Skills.

Visual-verbal paired associate learning (PAL) refers to the ability to establish an arbitrary association between a visual referent and an unfamiliar label. It is now established that this ability is impaired in children with dyslexia, but the source of this deficit is yet to be specified. This study assesses PAL performance in children with reading difficulties using a modified version of the PAL paradigm, comprising a comprehension and a production phase, to determine whether the PAL deficit lies in children's ability to establish and retain novel object-novel word associations or their ability to retrieve the learned novel labels for production. Results showed that while children with reading difficulties required significantly more trials to learn the object-word associations, when they were required to use these associations in a comprehension-referent selection task, their accuracy and speed did not differ from controls. Nevertheless, children with reading difficulties were significantly less successful when they were required to produce the learned novel labels in response to the visual stimuli. Thus, these results indicate that while children with reading difficulties are successful at establishing visual-verbal associations, they have a deficit in the verbal production component of PAL tasks, which may relate to a more general underlying impairment in auditory or phonological processing. Copyright © 2016 John Wiley & Sons, Ltd.