Remembering new words: integrating early memory development into word learning

Dogs with a vocabulary of object labels retain them for at least 2 years

Long-term memory of words has a crucial role in the developing abilities of young children to acquire language. In dogs, the ability to learn object labels is present in only a small group of uniquely gifted word learner (GWL) dogs. As they are very rare, little is known about the mechanisms through which they acquire such large vocabularies. In the current study, we tested the ability of five GWL dogs to retrieve 12 labelled objects 2 years after the object-label mapping acquisition. The dogs proved to remember the labels of between three and nine objects. The results shed light on the process by which GWL dogs acquire an exceptionally large vocabulary of object names. As memory plays a crucial role in language development, these dogs provide a unique opportunity to study label retention in a non-linguistic species.

Effects of conflicting emotional cues on toddlers' emotion perception

The communication of emotion is dynamic and occurs across multiple channels, such as facial expression and tone of voice. When cues are in conflict, interpreting emotion can become challenging. Here, we examined the effects of incongruent emotional cues on toddlers' interpretation of emotions. We presented 33 children (22-26 months, Mage = 23.8 months, 15 female) with side-by-side images of faces along with sentences spoken in a tone of voice that conflicted with semantic content. One of the two faces matched the emotional tone of the audio, whereas the other matched the semantic content. For both congruent and incongruent trials, toddlers showed no overall looking preference to either type of face stimuli. However, during the second exposure to the sentences of incongruent trials, older children tended to look longer to the face matching semantic content when listening to happy vs. angry content. Results inform our understanding of the early development of complex emotion understanding.

Fostering retention of word learning: The number of training sessions children retrieve words positively relates to post-training retention

During vocabulary instruction, it is important to teach words until their representations are robust enough to be retained. For adults, the number of training sessions a target item is successfully retrieved during training predicts the likelihood of post-training retention. To assess this relationship in children, we reanalyzed data from Gordon et al. (2021b, 2022). Four- to six-year-old children completed six training days with word form-object pairs and were tested one month later. Results indicate that the number of training sessions that a word form was retrieved was positively related to post-training retention. We discuss implications for vocabulary instruction and interventions.

Children build their vocabularies in noisy environments: The necessity of a cross-disciplinary approach to understand word learning

Research within the language sciences has informed our understanding of how children build vocabulary knowledge especially during early childhood and the early school years. However, to date, our understanding of word learning in children is based primarily on research in quiet laboratory settings. The everyday environments that children inhabit such as schools, homes, and day cares are typically noisy. To better understand vocabulary development, we need to understand the effects of background noise on word learning. To gain this understanding, a cross-disciplinary approach between researchers in the language and hearing sciences in partnership with parents, educators, and clinicians is ideal. Through this approach we can identify characteristics of effective vocabulary instruction that take into account the background noise present in children's learning environments. Furthermore, we can identify characteristics of children who are likely to struggle with learning words in noisy environments. For example, differences in vocabulary knowledge, verbal working memory abilities, and attention skills will likely influence children's ability to learn words in the presence of background noise. These children require effective interventions to support their vocabulary development which subsequently should support their ability to process and learn language in noisy environments. Overall, this cross-disciplinary approach will inform theories of language development and inform educational and intervention practices designed to support children's vocabulary development. This article is categorized under: Psychology > Language Psychology > Learning Psychology > Theory and Methods.

Can Infants Retain Statistically Segmented Words and Mappings Across a Delay?

Infants are sensitive to statistics in spoken language that aid word-form segmentation and immediate mapping to referents. However, it is not clear whether this sensitivity influences the formation and retention of word-referent mappings across a delay, two real-world challenges that learners must overcome. We tested how the timing of referent training, relative to familiarization with transitional probabilities (TPs) in speech, impacts English-learning 23-month-olds' ability to form and retain word-referent mappings. In Experiment 1, we tested infants' ability to retain TP information across a 10-min delay and use it in the service of word learning. Infants successfully mapped high-TP but not low-TP words to referents. In Experiment 2, infants readily mapped the same words even when they were unfamiliar. In Experiment 3, high- and low-TP word-referent mappings were trained immediately after familiarization, and infants readily remembered these associations 10 min later. In sum, although 23-month-old infants do not need strong statistics to map word forms to referents immediately, or to remember those mappings across a delay, infants are nevertheless sensitive to these statistics in the speech stream, and they influence mapping after a delay. These findings suggest that, by 23 months of age, sensitivity to statistics in speech may impact infants' language development by leading word forms with low coherence to be poorly mapped following even a short period of consolidation.

Cognitive and neural mechanisms underlying false memories: misinformation, distortion or erroneous configuration?

Errors can affect our memory, yet even when there are gaps in our recollection of events, memory often serves us fairly well. Memory formation involves at least three different sub-processes, that are regulated by an underlying neural structure. From a cognitive neuropsychological perspective, a complex process of encoding, consolidating, and retrieval is involved in remembering an event, and it might be hindered by one's emotional state, physiological response to the event itself, and misinformation. As a result, it is very likely that one may struggle to remember specifics of what happened which can increase our susceptibility to the formation of false memories. This has major implications for everyday functioning, as in the case when you mistakenly remember you took your pills when you never did, or where errors have led to false accusations about trauma or abuse, and wrongful convictions of crimes. Memories sometimes contain biases and inaccuracies that prevent them from accurately recalling events. The review will provide an updated overview of current research advances on the cognitive and neural mechanisms underlying inaccurate, distorted, or false memories.

Examining the Relation Between Exercise and Word Learning in Preschool-Age Children

PURPOSE

There is evidence suggesting that aerobic exercise immediately after vocabulary training can improve word recall in school-age children. This work examined whether the previously identified word-learning benefits associated with exercise can be extended to preschoolers. Additionally, we evaluated whether the effects of physical activity on vocabulary learning may be influenced by existing language skills that the child possesses.

METHOD

Children ages 3-6 years completed the study (N = 42). Data were collected via a virtual testing session in which participants completed a word-learning task that included two experimental conditions (exercise and resting). In the resting measure, children were taught names of novel objects and then sat down and colored for 3 min before being tested on their ability to identify the trained words. The exercise condition was identical, except that participants engaged in 3 min of guided aerobic exercise before testing. Additionally, at the end of the visit, participants completed the Quick Interactive Language Screener (QUILS), which measured general language skills.

RESULTS

Accuracy of word recognition was significantly higher after the exercise condition compared to the resting condition. Furthermore, this pattern of results was not related to children's existing language skills, as measured by the QUILS.

CONCLUSIONS

This study is one of the first to closely examine the relation between physical activity and word-learning abilities in children as young as 3-6 years of age. Results align with previous findings stating that aerobic exercise can boost vocabulary learning and suggest that this is the case regardless of existing language skills.

Effect of Cannabis on Memory Consolidation, Learning and Retrieval and Its Current Legal Status in India: A Review

Cannabis is one of the oldest crops grown, traditionally held religious attachments in various cultures for its medicinal use much before its introduction to Western medicine. Multiple preclinical and clinical investigations have explored the beneficial effects of cannabis in various neurocognitive and neurodegenerative diseases affecting the cognitive domains. Tetrahydrocannabinol (THC), the major psychoactive component, is responsible for cognition-related deficits, while cannabidiol (CBD), a non-psychoactive phytocannabinoid, has been shown to elicit neuroprotective activity. In the present integrative review, the authors focus on the effects of cannabis on the different cognitive domains, including learning, consolidation, and retrieval. The present study is the first attempt in which significant focus has been imparted on all three aspects of cognition, thus linking to its usage. Furthermore, the investigators have also depicted the current legal position of cannabis in India and the requirement for reforms.

Discourse with Few Words: Coherence Statistics, Parent-Infant Actions on Objects, and Object Names

The data for early object name learning is often conceptualized as a problem of mapping heard names to referents. However, infants do not hear object names as discrete events but rather in extended interactions organized around goal-directed actions on objects. The present study examined the statistical structure of the nonlinguistic events that surround parent naming of objects. Parents and 12-month -old infants were left alone in a room for 10 minutes with 32 objects available for exploration. Parent and infant handling of objects and parent naming of objects were coded. The four measured statistics were from measures used in the study of coherent discourse: (1) a frequency distribution in which actions were frequently directed to a few objects and more rarely to other objects; (2) repeated returns to the high-frequency objects over the 10-minute play period; (3) clustered repetitions, continuity, of actions on objects; and (4) structured networks of transitions among objects in play that connected all the played-with objects. Parent naming was infrequent but related to the statistics of object-directed actions. The implications of the discourse-like stream of actions are discussed in terms of learning mechanisms that could support rapid learning of object names from relatively few name-object co-occurrences.

Word Learning by Preschool-Age Children: Differences in Encoding, Re-Encoding, and Consolidation Across Learners During Slow Mapping

PURPOSE

Children with typical development vary in how much experience they need to learn words. This could be due to differences in the amount of information encoded during periods of input, consolidated between periods of input, or both. Our primary purpose is to identify whether encoding, consolidation, or both, drive individual differences in the slow-mapping process.

METHOD

Four- to 6-year-old children (N = 43) were trained on nine form-referent pairs across consecutive days. Children's ability to name referents was assessed at the beginning and end of each session. Word learning was assessed 1 month after training to determine long-term retention.

RESULTS

Children with varying language knowledge and skills differed in their ability to encode words. Specifically, children varied in the number of words learned and the phonological precision of word forms at the end of the initial training session. Children demonstrated similarities in re-encoding in that they refined representations at a similar rate during subsequent sessions. Children did not differ in their ability to consolidate words between sessions, or in their ability to retain words over the 1-month delay.

CONCLUSIONS

The amount of experience children need to learn words is primarily driven by the amount of information encoded during the initial experience. When provided with high-quality instruction, children demonstrate a similar ability to consolidate and retain words. Critically, word learning instruction in educational settings must include repeated explicit instruction with the same words to support learning in children with typical development and varying language skills.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.19606150.

Evaluating the Effect of Rich Vocabulary Instruction and Retrieval Practice on the Classroom Vocabulary Skills of Children With (Developmental) Language Disorder

PURPOSE

Learning new vocabulary has been identified as a challenge for students with (developmental) language disorder ((D)LD). In this study, we evaluate the effects of two active learning methods, (a) retrieval practice (RP) and (b) rich vocabulary instruction (RVI), in a group of students with (D)LD in secondary school.

METHOD

A quasi-experimental counterbalanced within-subject design was used to compare and evaluate the effect of RP and RVI on learning Tier 2 vocabulary, with target and control words as dependent measures. Eleven students with (D)LD (M _age = 14.9 years) attending a language unit participated. RP and RVI were implemented in regular classroom activities during 16 lessons (eight lessons/instructional condition). Learning was assessed by comparing performance on a pretest session 1-2 weeks prior, with posttest performance 1 week after each instructional condition.

RESULTS

The learning gain for RP was superior to that for RVI, both with respect to the Bayesian probabilistic estimations for target words relative to control words and in direct comparison with RVI. Only weak evidence was found for RVI with respect to the Bayesian probabilistic estimations for target words relative to control words.

CONCLUSIONS

All participants showed positive learning gains following RP, whereas the outcome for RVI was more diverse. This initial work suggests that RP promotes larger learning gains relative to RVI and promotes learning across language profiles. This study extends previous studies by exploring the implementation of RP in regular classroom activities and by using more complex to-be-learned material (Tier 2 words).

Learning new words: Memory reactivation as a mechanism for strengthening and updating a novel word's meaning

In the present study we explored the postlearning changes in a novel word's definition using a cue-induced memory reactivation. Native speakers of Spanish (N = 373) learned low-frequency words with their corresponding definitions. The following day, reactivated groups were exposed to a reminder and provided a subjective assessment of reactivation for each word, while control groups did not receive a reactivation. Study A demonstrated that memory reactivation enhances both explicit recall and semantic integration of new meanings. Study B investigated the effect of memory reactivation in the modification of the new meanings, through three different experiments. Results show an improvement of the updated definitions according to each word's reactivation strength. In addition, congruence with previous knowledge was suggested to be a boundary condition, while consolidation time had a positive modulatory effect. Our findings call attention to reactivation as a factor allowing for malleability as well as persistence of long-term memories for words.

Prior Exposure and Toddlers' Sleep-Related Memory for Novel Words

Children can easily link a novel word to a novel, unnamed object—something referred to as fast mapping. Despite the ease and speed with which children do this, their memories for novel fast-mapped words can be poor unless they receive memory supports such as further exposure to the words or sleep. Axelsson, Swinton, Winiger, and Horst (2018) found that 2.5-year-old children who napped after fast mapping had better retention of novel words than children who did not nap. Retention declined for those who did not nap. The children received no memory supports and determined the word-object mappings independently. Previous studies report enhanced memories after sleeping in children and adults, but the napping children’s retention in the Axelsson et al. study remained steady across time. We report a follow-up investigation where memory supports are provided after fast mapping to test whether memories would be enhanced following napping. Children’s retention of novel words improved and remained greater than chance; however, there was no nap effect with no significant difference between the children who napped and those who did not. These findings suggest that when memory supports are provided, retention improves, and the word–object mappings remain stable over time. When memory traces are weak and labile, such as after fast mapping, without further memory supports, sleeping soon after helps stabilise and prevent decay of word–object mappings.

The Role of Sleep in Retention of New Words in Habitually and Non-Habitually Napping Children

Daytime napping contributes to retention of new word learning in children. Importantly, children transition out of regular napping between ages 3–5 years, and the impact of this transition on memory is unclear. Here, we examined the performance of both non-habitually napping children (nap 0–3 days per week, n = 28) and habitually napping children (nap 4–7 days per week, n = 30) on a word learning task after a delay including either sleep or wakefulness. Children ages 3.5–4.5 years old experienced a brief exposure to two novel labels and their referents during training, a scenario that replicates learning experiences children encounter every day. After a 4-h delay, children were tested on the object-label associations. Using mixed effects logistic regression, we compared retention performance. Non-habitual nappers and habitual nappers displayed a different pattern of retention such that non-habitually napping children did equally well on a test of retention regardless of whether they napped or stayed awake during the delay. In contrast, habitually napping children needed a nap after learning to retain the novel object-label associations 4 h later. As a group, habitual nappers who remained awake after learning performed no better than chance on the retention test. As children transition out of naps, they may be less susceptible to interference and are better able to retain newly learned words across a delay including wakefulness.

A multi-study examination of the role of repeated spaced retrieval in the word learning of children with developmental language disorder

BACKGROUND

Many children with developmental language disorders (DLD) have well-documented weaknesses in vocabulary. In recent years, investigators have explored the nature of these weaknesses through the use of novel word learning paradigms. These studies have begun to uncover specific areas of difficulty and have provided hints about possible intervention strategies that might help these children learn words more accurately and efficiently. Among the studies of this type are those that incorporate repeated spaced retrieval activities in the learning procedures.

METHODS

In this study, we examined the data from four of these studies that employed the same types of participants (4- and 5-year-old children with DLD and same-age children with typical language development), research design, and outcome measures. The studies differed primarily in the type of learning condition that was being compared to a spaced retrieval condition. A mixed-effects modeling framework was used, enabling the data from the four studies and different outcome measures to be aggregated.

RESULTS

Across the studies, more words in the repeated spaced retrieval condition were recalled than those in the comparison conditions. This was true regardless of outcome measure. Children with typical language development recalled more words than the children with DLD. Both groups benefited from spaced retrieval, though effects were larger for the group with DLD. Children recalled words as accurately 1 week after learning as they did at the 5-min mark; the two groups were essentially identical in this respect.

CONCLUSIONS

Overall, the findings support the continued refinement of these types of repeated spaced retrieval procedures, as they may have potential to serve as effective approaches to intervention.

Progressive Reduction of Iconic Gestures Contributes to School-Aged Children's Increased Word Production

The economic principle of communication, according to which successful communication can be reached by least effort, has been studied for verbal communication. With respect to nonverbal behavior, it implies that forms of iconic gestures change over the course of communication and become reduced in the sense of less pronounced. These changes and their effects on learning are currently unexplored in relevant literature. Addressing this research gap, we conducted a word learning study to test the effects of changing gestures on children's slow mapping. We applied a within-subject design and tested 51 children, aged 6.7 years (SD = 0.4), who learned unknown words from a story. The storyteller acted on the basis of two conditions: In one condition, in which half of the target words were presented, the story presentation was enhanced with progressively reduced iconic gestures (PRG); in the other condition, half of the target words were accompanied by fully executed iconic gestures (FEG). To ensure a reliable gesture presentation, children were exposed to a recorded person telling a story in both conditions. We tested the slow mapping effects on children's productive and receptive word knowledge three minutes as well as two to three days after being presented the story. The results suggest that children's production of the target words, but not their understanding thereof, was enhanced by PRG.

Evidence for Enhanced Long-term Memory in Professional Musicians and Its Contribution to Novel Word Learning

Previous studies evidenced transfer effects from professional music training to novel word learning. However, it is unclear whether such an advantage is driven by cascading, bottom-up effects from better auditory perception to semantic processing or by top-down influences from cognitive functions on perception. Moreover, the long-term effects of novel word learning remain an open issue. To address these questions, we used a word learning design, with four different sets of novel words, and we neutralized the potential perceptive and associative learning advantages in musicians. Under such conditions, we did not observe any advantage in musicians on the day of learning (Day 1 [D1]), at neither a behavioral nor an electrophysiological level; this suggests that the previously reported advantages in musicians are likely to be related to bottom-up processes. Nevertheless, 1 month later (Day 30 [D30]) and for all types of novel words, the error increase from D1 to D30 was lower in musicians compared to nonmusicians. In addition, for the set of words that were perceptually difficult to discriminate, only musicians showed typical N400 effects over parietal sites on D30. These results demonstrate that music training improved long-term memory and that transfer effects from music training to word learning (i.e., semantic levels of speech processing) benefit from reinforced (long-term) memory functions. Finally, these findings highlight the positive impact of music training on the acquisition of foreign languages.

Modeling the Influence of Language Input Statistics on Children's Speech Production

We trained a computational model (the Chunk-Based Learner; CBL) on a longitudinal corpus of child-caregiver interactions in English to test whether one proposed statistical learning mechanism-backward transitional probability-is able to predict children's speech productions with stable accuracy throughout the first few years of development. We predicted that the model less accurately reconstructs children's speech productions as they grow older because children gradually begin to generate speech using abstracted forms rather than specific "chunks" from their speech environment. To test this idea, we trained the model on both recently encountered and cumulative speech input from a longitudinal child language corpus. We then assessed whether the model could accurately reconstruct children's speech. Controlling for utterance length and the presence of duplicate chunks, we found no evidence that the CBL becomes less accurate in its ability to reconstruct children's speech with age.

Sampling to learn words: Adults and children sample words that reduce referential ambiguity

How do learners gather new information during word learning? One possibility is that learners selectively sample items that help them reduce uncertainty about new word meanings. In a series of cross-situational word learning tasks with adults and children, we manipulated the referential ambiguity of label-object pairs experienced during training and subsequently investigated which words participants chose to sample additional information about. In the first experiment, adult learners chose to receive additional training on object-label associations that reduce referential ambiguity during cross-situational word learning. This ambiguity-reduction strategy was related to improved test performance. In two subsequent experiments, we found that, at least in some contexts, children (3-8 years of age) show a similar preference to seek information about words experienced in ambiguous word learning situations. In Experiment 2, children did not preferentially select object-label associations that remained ambiguous during cross-situational word learning. However, in a third experiment that increased the relative ambiguity of two sets of novel object-label associations, we found evidence that children preferentially make selections that reduce ambiguity about novel word meanings. These results carry implications for understanding how children actively contribute to their own language development by seeking information that supports learning.

24-Month-olds and over remember novel object names after a single learning event

In the context of word learning, it is commonly assumed that repetition is required for young children to form and maintain in memory an association between a novel word and its corresponding object. For instance, at 2 years of age, children are able to disambiguate word-related situations in one shot but are not able to further retain this newly acquired knowledge. It has been proposed that multiple fast-mapping experiences would be required to promote word retention or that the inferential reasoning needs to be accompanied by explicit labeling of the target. We hypothesized that when 2-year-olds simply encounter an unambiguous learning context, word learning may be fast and maintained in time. We also assumed that, under this condition, even a single exposure to an object would be sufficient to form a memory trace of its name that would survive a delay. To test these hypotheses, 2- and 4-year-olds were ostensively taught three arbitrary word-object pairs using a 15-s video sequence during which each object was manually displayed and labeled three times in a row. Retention was measured after a 30-min distractive period using a forced-choice procedure. Our results provide evidence that declarative memory does not need repetition to be formed and maintained, for at least a 30-min period, by children as young as 2 years. This finding suggests that the mechanisms required for extremely rapid and robust word acquisition not only are present in preschoolers with developed language and cognitive skills but also are already operative at a younger age.

Optimal Contexts for Verb Learning

Purpose

Verb learning is a critical but challenging part of language acquisition. Children with or at increased risk for developmental language disorder (DLD) may particularly struggle with verb learning, and poor verb representations in turn may negatively impact children's language outcomes. Our goal is to examine literature on children's acquisition of verbs, identifying manipulable factors that may determine the ease or difficulty of acquiring a new verb meaning.

Method

In this narrative, non-systematic review, we discuss findings about how verbs are learned and represented.

Results

Several aspects of the learning environment affect children's efforts to acquire verbs, including the linguistic context in which the verb is introduced, the timing of the linguistic label relative to the event it describes, visual and linguistic variability, and dose frequency.

Conclusions

We conclude that some learning situations are likely to be more helpful for children in the process of verb learning than others. We highlight some of the factors that contribute to good learning situations, and we discuss how these may differ depending on properties of the child and of the verb itself. Finally, we propose hypotheses for future translational and clinical research.

The Impact of Dose and Dose Frequency on Word Learning by Kindergarten Children With Developmental Language Disorder During Interactive Book Reading

Purpose

The goal was to determine whether interactive book reading outcomes for children with developmental language disorder (DLD) were affected by manipulation of dose (i.e., the number of exposures to the target word during a book reading session) and dose frequency (i.e., the number of repeated book reading sessions) and whether pretreatment factors predicted treatment response variation.

Method

Thirty-four kindergarten children with DLD (aged 5;0–6;2 [years;months]) were taught 1 set of words using the Dose 6 and Dose Frequency 6 format from a prior study (Storkel, Voelmle, et al., 2017) and taught a different set of words using an alternative format, either Dose 4 × Dose Frequency 9 or Dose 9 × Dose Frequency 4, determined through random assignment. Word learning was tracked for each treatment via a definition task prior to, during, and after treatment.

Results

Results showed that children with DLD learned a significant number of words during treatment regardless of the dose and dose frequency format but that significant forgetting of newly learned words occurred in all formats once treatment was withdrawn. Individual differences in word learning were related to Clinical Evaluation of Language Fundamentals Core Language and Understanding Spoken Paragraphs scores.

Conclusion

When administered at an adequate intensity, variation in the dose and dose frequency of interactive book reading does not appear to influence word learning by children with DLD. Although interactive book reading continues to show promise as an effective word learning intervention for children with DLD, further development is needed to enhance the effectiveness of this treatment approach.

Supplemental Material

https://doi.org/10.23641/asha.9745181

Novel word learning at 21 months predicts receptive vocabulary outcomes in later childhood

Several aspects of early language skills, including parent-report measures of vocabulary, phoneme discrimination, speech segmentation, and speed of lexical access predict later childhood language outcomes. To date, no studies have examined the long-term predictive validity of novel word learning. We examined whether individual differences in novel word learning at 21 months predict later childhood receptive vocabulary outcomes rather than generalized cognitive abilities. Twenty-eight 21-month-olds were taught novel words using a modified version of the Intermodal Preferential Looking Paradigm. Seventeen children (range 7-10 years) returned to participate in a longitudinal follow-up. Novel word learning in infancy uniquely accounted for 22% of the variance in childhood receptive vocabulary but did not predict later childhood visuospatial ability or non-verbal IQ. These results suggest that the ability to associate novel sound patterns to novel objects, an index of the process of word learning, may be especially important for long-term language mastery.

The role of complementary learning systems in learning and consolidation in a quasi-regular domain

We examine the role of off-line memory consolidation processes in the learning and retention of a new quasi-regular linguistic system similar to the English past tense. Quasi-regular systems are characterized by a dominance of systematic, regular forms (e.g., walk-walked, jump-jumped) alongside a smaller number of high frequency irregulars (e.g., sit-sat, go-went), and are found across many cognitive domains, from spelling-sound mappings to inflectional morphology to semantic cognition. Participants were trained on the novel morphological system using an artificial language paradigm, and then tested after different delays. Based on a complementary systems account of memory, we predicted that irregular forms would show stronger off-line changes due to consolidation processes. Across two experiments, participants were tested either immediately after learning, 12 h later with or without sleep, or 24 h later. Testing involved generalization of the morphological patterns to previously unseen words (both experiments) as well as recall of the trained words (Experiment 2). In generalization, participants showed 'default' regularization across a range of novel forms, as well as irregularization for previously unseen items that were similar to unique high-frequency irregular trained forms. Both patterns of performance remained stable across the delays. Generalizations involving competing tendencies to regularize and irregularize were balanced between the two immediately after learning. Crucially, at both 12-h delays the tendency to irregularize in these cases was strengthened, with further strengthening after 24 h. Consolidated knowledge of both regular and irregular trained items contributed significantly to generalization performance, with evidence of strengthening of irregular forms and weakening of regular forms. We interpret these findings in the context of a complementary systems model, and discuss how maintenance, strengthening, and forgetting of the new memories across sleep and wake can play a role in acquiring quasi-regular systems.

The longevity of statistical learning: When infant memory decays, isolated words come to the rescue

Research over the past 2 decades has demonstrated that infants are equipped with remarkable computational abilities that allow them to find words in continuous speech. Infants can encode information about the transitional probability (TP) between syllables to segment words from artificial and natural languages. As previous research has tested infants immediately after familiarization, infants' ability to retain sequential statistics beyond the immediate familiarization context remains unknown. Here, we examine infants' memory for statistically defined words 10 min after familiarization with an Italian corpus. Eight-month-old English-learning infants were familiarized with Italian sentences that contained 4 embedded target words-2 words had high internal TP (HTP, TP = 1.0) and 2 had low TP (LTP, TP = .33)-and were tested on their ability to discriminate HTP from LTP words using the Headturn Preference Procedure. When tested after a 10-min delay, infants failed to discriminate HTP from LTP words, suggesting that memory for statistical information likely decays over even short delays (Experiment 1). Experiments 2-4 were designed to test whether experience with isolated words selectively reinforces memory for statistically defined (i.e., HTP) words. When 8-month-olds were given additional experience with isolated tokens of both HTP and LTP words immediately after familiarization, they looked significantly longer on HTP than LTP test trials 10 min later. Although initial representations of statistically defined words may be fragile, our results suggest that experience with isolated words may reinforce the output of statistical learning by helping infants create more robust memories for words with strong versus weak co-occurrence statistics. (PsycINFO Database Record

Learning Spoken Words via the Ears and Eyes: Evidence from 30-Month-Old Children

From the very first moments of their lives, infants are able to link specific movements of the visual articulators to auditory speech signals. However, recent evidence indicates that infants focus primarily on auditory speech signals when learning new words. Here, we ask whether 30-month-old children are able to learn new words based solely on visible speech information, and whether information from both auditory and visual modalities is available after learning in only one modality. To test this, children were taught new lexical mappings. One group of children experienced the words in the auditory modality (i.e., acoustic form of the word with no accompanying face). Another group experienced the words in the visual modality (seeing a silent talking face). Lexical recognition was tested in either the learning modality or in the other modality. Results revealed successful word learning in either modality. Results further showed cross-modal recognition following an auditory-only, but not a visual-only, experience of the words. Together, these findings suggest that visible speech becomes increasingly informative for the purpose of lexical learning, but that an auditory-only experience evokes a cross-modal representation of the words.

Preschoolers' Acquisition of Novel Verbs in the Double Object Dative

Children have difficulty comprehending novel verbs in the double object dative (e.g., Fred blicked the dog a stick) as compared to the prepositional dative (e.g., Fred blicked a stick to the dog). We explored this pattern with 3 and 4 year olds (N = 60). In Experiment 1, we replicated the documented difficulty with the double object frame, even though we provided more contextual support. In Experiment 2, we tested a novel hypothesis that children would comprehend novel verbs in, and generalize them to, the double object frame if they were first familiarized to the verbs in the prepositional frame. They did, suggesting that part of their difficulty with the double object frame is due to uncertainty about a new verb's semantic/syntactic properties, information that the easy-to-comprehend prepositional frame provides. The benefits of training were short-lived, however; children again struggled after a 2-h delay. The results are discussed in the context of mechanisms underlying verb acquisition.

Consolidation of vocabulary during sleep: The rich get richer?

Sleep plays a role in strengthening new words and integrating them with existing vocabulary knowledge, consistent with neural models of learning in which sleep supports hippocampal transfer to neocortical memory. Such models are based on adult research, yet neural maturation may mean that the mechanisms supporting word learning vary across development. Here, we propose a model in which children may capitalise on larger amounts of slow-wave sleep to support a greater demand on learning and neural reorganisation, whereas adults may benefit from a richer knowledge base to support consolidation. Such an argument is reinforced by the well-reported "Matthew effect", whereby rich vocabulary knowledge is associated with better acquisition of new vocabulary. We present a meta-analysis that supports this association between children's existing vocabulary knowledge and their integration of new words overnight. Whilst multiple mechanisms likely contribute to vocabulary consolidation and neural reorganisation across the lifespan, we propose that contributions of existing knowledge should be rigorously examined in developmental studies. Such research has potential to greatly enhance neural models of learning.

2.5-year-olds' retention and generalization of novel words across short and long delays

Two experiments investigated two-year-olds' retention and generalization of novel words across short and long time delays. Specifically, retention of newly learned words and generalization to novel exemplars or novel contexts were tested one minute or one week after learning. Experiment 1 revealed successful retention as well as successful generalization to both new exemplars and new contexts after a one-minute delay, with no statistical differences between retention and generalization performance for either generalization type. Toddlers tested after a week delay (Experiment 2) showed successful retention and generalization as well, but while context generalization was statistically equivalent to retention accuracy, exemplar generalization was significantly lower than retention accuracy. The overall success in both retention and generalization suggests that toddlers' newly learned words are robust and flexible. However, the lower exemplar generalization performance compared to retention after a weeklong delay suggests that novel words may become less flexible across exemplar characteristics over time.

Can 28-Month-Old Children Learn Spatial Prepositions Robustly from Pictures? Yes, When Narrative Input Is Provided

The learning of spatial prepositions is assumed to be based on experience in space. In a slow mapping study, we investigated whether 31 German 28-month-old children could robustly learn the German spatial prepositions hinter [behind] and neben [next to] from pictures, and whether a narrative input can compensate for a lack of immediate experience in space. One group of children received pictures with a narrative input as a training to understand spatial prepositions. In two further groups, we controlled (a) for the narrative input by providing unconnected speech during the training and (b) for the learning material by training the children on toys rather than pictures. We assessed children's understanding of spatial prepositions at three different time points: pretest, immediate test, and delayed posttest. Results showed improved word retention in children from the narrative but not the control group receiving unconnected speech. Neither of the trained groups succeeded in generalization to novel referents. Finally, all groups were instructed to deal with untrained material in the test to investigate the robustness of learning across tasks. None of the groups succeeded in this task transfer.

An Alternative to Mapping a Word onto a Concept in Language Acquisition: Pragmatic Frames

The classic mapping metaphor posits that children learn a word by mapping it onto a concept of an object or event. However, we believe that a mapping metaphor cannot account for word learning, because even though children focus attention on objects, they do not necessarily remember the connection between the word and the referent unless it is framed pragmatically, that is, within a task. Our theoretical paper proposes an alternative mechanism for word learning. Our main premise is that word learning occurs as children accomplish a goal in cooperation with a partner. We follow Bruner's (1983) idea and further specify pragmatic frames as the learning units that drive language acquisition and cognitive development. These units consist of a sequence of actions and verbal behaviors that are co-constructed with a partner to achieve a joint goal. We elaborate on this alternative, offer some initial parametrizations of the concept, and embed it in current language learning approaches.

Learning verb syntax via listening: New evidence from 22-month-olds

Children recruit verb syntax to guide verb interpretation. We asked whether 22-month-olds spontaneously encode information about a particular novel verb's syntactic properties through listening to sentences, retain this information in long-term memory over a filled delay, and retrieve it to guide interpretation upon hearing the same novel verb again. Children watched dialogues in which interlocutors discussed unseen events using a novel verb in transitive (e.g., "Anna blicked the baby") or intransitive sentences ("Anna blicked"). Children later heard the verb in isolation ("Find blicking!") while viewing a two-participant causal action and a one-participant action event. Children who had heard transitive dialogues looked longer at the two-participant event than did those who heard intransitive dialogues. This effect disappeared if children heard a different novel verb at test ("Find kradding!"). These findings implicate a role for distributional learning in early verb learning: Syntactic-combinatorial information about otherwise unknown words may pervade the toddler's lexicon, guiding later word interpretation.

Verbal positional memory in 7-month-olds

Verbal memory is a fundamental prerequisite for language learning. This study investigated 7-month-olds' (N = 62) ability to remember the identity and order of elements in a multisyllabic word. The results indicate that infants detect changes in the order of edge syllables, or the identity of the middle syllables, but fail to encode the order of middle syllables. This suggests that the representational format of multisyllabic words is determined by core mnemonic biases, which favor accurate encoding of edges and limits the encoding of temporal order for internal segments. The studies support accounts proposing that content and order are encoded separately; in addition, the data show that this dissociation occurs early in development.