Comparison Versus Contrast: Task Specifics Affect Category Acquisition: Comparison Versus Contrast

The effects of speaker and exemplar variability in children's cross-situational word learning

Cross-situational word learning (XSWL) - children's ability to learn words by tracking co-occurrence statistics of words and their referents over time - has been identified as a fundamental mechanism underlying lexical learning. However, it is unknown whether children can acquire new words when faced with variable input in XSWL paradigms, such as varying object exemplars and variable speakers. In the present study, we examine the separate and combined effects of exemplar and speaker variability on XSWL in typically developing English-speaking monolingual children. Results revealed that variability in speakers and exemplars did not facilitate or hinder XSWL performance. However, input that varied in both speakers and exemplars simultaneously did hinder children's word learning. Results from this work suggest that XSWL mechanisms may support categorization and generalization beyond word-object associations, but that accommodating multiple forms of variable input may incur costs. Overall, this research provides new theoretical insights into how fundamental mechanisms of word learning scale to more complex and naturalistic forms of input.

The effects of bilingualism on children's cross-situational word learning under different variability conditions

In the current study, we examined the separate and combined effects of exemplar and speaker variability on monolingual and bilingual children's cross-situational word learning performance. Results revealed that children's word learning performance did not differ when the input varied in a single dimension (i.e., exemplars or speakers) compared with a condition with no variability independent of their linguistic background. However, when performance in conditions that varied in a single dimension (i.e., exemplars or speakers) was compared with a condition that varied in multiple dimensions (i.e., exemplars and speakers), bilingual word learning advantages were observed; bilinguals were more likely to learn word-referent associations than monolinguals. Together, results suggest that children can learn and generalize word-referent associations from input that varies in exemplars and speakers and that bilingualism may bolster learning under conditions of increased input variability.

One versus many: Multiple examples in word learning

A large body of research indicates that children can map words to categories and generalize the label to new instances of the category after hearing a single instance of the category labeled. Additional research demonstrates that word learning is enhanced when children are presented with multiple instances of a category through comparison or contrast. In this study, 3-year-old children participated in a novel noun generalization task in which a label was given for either (a) a single instance of a category, (b) multiple instances of a category, or (c) contrasting a category instance with non-category members. Children were asked to extend the label to a new category at test either immediately (Study 1) or after a 10-s delay (Study 2). The results indicate that when tested immediately, children who heard a single instance labeled outperformed children who were presented with multiple instances. However, when tested after a brief delay, there was no difference among the conditions.

Caregivers use gesture contingently to support word learning

Children learn words in environments where there is considerable variability, both in terms of the number of possible referents for novel words, and the availability of cues to support word-referent mappings. How caregivers adapt their gestural cues to referential uncertainty has not yet been explored. We tested a computational model of cross-situational word learning that examined the value of a variable gesture cue during training across conditions of varying referential uncertainty. We found that gesture had a greater benefit for referential uncertainty, but unexpectedly also found that learning was best when there was variability in both the environment (number of referents) and gestural cue use. We demonstrated that these results are reflected behaviourally in an experimental word-learning study involving children aged 18-24-month-olds and their caregivers. Under similar conditions to the computational model, caregivers not only used gesture more when there were more potential referents for novel words, but children also learned best when there was some referential ambiguity for words. Thus, caregivers are sensitive to referential uncertainty in the environment and adapt their gestures accordingly, and children are able to respond to environmental variability to learn more robustly. These results imply that training under variable circumstances may actually benefit learning, rather than hinder it.

Consistency of co-occurring actions influences young children's word learning

Communication with young children is often multimodal in nature, involving, for example, language and actions. The simultaneous presentation of information from both domains may boost language learning by highlighting the connection between an object and a word, owing to temporal overlap in the presentation of multimodal input. However, the overlap is not merely temporal but can also covary in the extent to which particular actions co-occur with particular words and objects, e.g. carers typically produce a hopping action when talking about rabbits and a snapping action for crocodiles. The frequency with which actions and words co-occurs in the presence of the referents of these words may also impact young children's word learning. We, therefore, examined the extent to which consistency in the co-occurrence of particular actions and words impacted children's learning of novel word-object associations. Children (18 months, 30 months and 36-48 months) and adults were presented with two novel objects and heard their novel labels while different actions were performed on these objects, such that the particular actions and word-object pairings always co-occurred (Consistent group) or varied across trials (Inconsistent group). At test, participants saw both objects and heard one of the labels to examine whether participants recognized the target object upon hearing its label. Growth curve models revealed that 18-month-olds did not learn words for objects in either condition, and 30-month-old and 36- to 48-month-old children learned words for objects only in the Consistent condition, in contrast to adults who learned words for objects independent of the actions presented. Thus, consistency in the multimodal input influenced word learning in early childhood but not in adulthood. In terms of a dynamic systems account of word learning, our study shows how multimodal learning settings interact with the child's perceptual abilities to shape the learning experience.

Family expressiveness relates to happy emotion matching among 9-month-old infants

Perceiving and understanding the emotions of those around us is an imperative skill to develop early in life. An infant's family environment provides most of their emotional exemplars in early development. However, the relation between the early development of emotion perception and family expressiveness remains understudied. To investigate this potential link to early emotion perception development, we examined 38 infants at 9 months of age. We assessed infants' ability to match emotions across facial and vocal modalities using an intermodal matching paradigm for angry-neutral, happy-neutral, and sad-neutral pairings. We also attained family expressiveness information via parent report. Our results indicate a significant positive relation between emotion matching and family expressiveness specific to the happy-neutral condition. However, we found no evidence for emotion matching for the infants as a group in any of the three conditions. These results suggest that family expressiveness does relate to emotion matching for the earliest developing emotional category among 9-month-old infants and that emotion matching with multiple emotions at this age is a challenging task.

All the Right Noises: Background Variability Helps Early Word Learning

Variability is prevalent in early language acquisition, but, whether it supports or hinders learning is unclear; while target variability has been shown to facilitate word learning, variability in competitor items has been shown to make the task harder. Here, we tested whether background variability could boost learning in a referent selection task. Two groups of 2-year-old children saw arrays of one novel and two known objects on a screen, and they heard a novel or known label. Stimuli were identical across conditions, with the exception that in the constant color condition objects appeared on a uniform white background, and in the variable color condition backgrounds were different, uniform colors. At test, only children in the variable condition showed evidence of retaining label-object associations. These data support findings from the adult memory literature, which suggest that variability supports learning by decontextualizing representations. We argue that these data are consistent with dynamic systems accounts of learning in which low-level entropy adds sufficient noise to the developmental system to precipitate a change in behavior.

Finding meaning in a noisy world: exploring the effects of referential ambiguity and competition on 2·5-year-olds' cross-situational word learning

While recent studies suggest children can use cross-situational information to learn words, these studies involved minimal referential ambiguity, and the cross-situational evidence overwhelmingly favored a single referent for each word. Here we asked whether 2·5-year-olds could identify a noun's referent when the scene and cross-situational evidence were more ambiguous. Children saw four trials in which a novel word occurred with four novel objects; only one object consistently co-occurred with the word across trials. The frequency of distracter objects varied across conditions. When all distracter referents occurred only once (no-competition), children successfully identified the noun's referent. When a high-probability competitor referent occurred on three trials, children identified the target referent if the competitor was absent on the third trial (short-competition) but not if it was present until the fourth trial (long-competition). This suggests that although 2·5-year-olds' cross-situational learning scales up to more ambiguous scenes, it is disrupted by high-probability competitor referents.

Not taking the easy road: When similarity hurts learning

Two experimental studies examined the effects of example format and example similarity on mathematical problem solving across different learning contexts. Participants were more successful inducing a correct problem-solving rule when they were provided with annotated examples rather than nonannotated examples. The effects of example similarity varied depending on learning context. In Experiment 1, by presenting an example and problem simultaneously, a direct comparison was possible between the cases. When the examples were similar, participants relied on superficial analogies that hurt learning. When an example was dissimilar from the given problem, participants appeared to study the example first to induce a solution procedure and then apply the rule to the problem, thus resulting in better learning and transfer. However, in Experiment 2 where the example and problem were presented in a sequential manner, the effect disappeared because the learning context did not support a direct comparison. We conclude that comparison is not inherently good for promoting learning and transfer, rather its effect depends on whether it supports relational mapping that is essential for schema acquisition.