The metacognitive disambiguation effect

From an early age, children show a tendency to map novel labels onto unfamiliar rather than familiar kinds of objects. Accounts of this tendency have not addressed whether children develop a metacognitive representation of what they are doing. In 3 experiments (each N = 48), preschoolers received a test of the metacognitive disambiguation effect, which involved deciding whether the referent of a novel label was located in a bucket of things “I know” or bucket of things “I don’t know.” Most 4-year-olds passed this test, whereas most 3-year-olds did not. Children’s performance was predicted by their ability to report whether various words and pseudowords were ones that they knew, even after age and vocabulary size were controlled. As children develop an awareness of their lexical knowledge/ignorance, they also develop a metacognitive representation of their tendency to map novel labels onto unfamiliar rather than familiar kinds.     

Rapid fast-mapping abilities in 2-year-olds

Learning a new word consists of two primary tasks that have often been conflated into a single process: referent selection, in which a child must determine the correct referent of a novel label, and referent retention, which is the ability to store this newly formed label-object mapping in memory for later use. In addition, children must be capable of performing these tasks rapidly and repeatedly as they are frequently exposed to novel words during the course of natural conversation. Here we used a preferential pointing task to investigate 2-year-olds’ (N = 72) ability to infer the referent of a novel noun from a single ambiguous exposure and their ability to retain this mapping over time. Children were asked to identify the referent of a novel label on six critical trials distributed throughout the course of a 10-min study involving many familiar and novel objects. On these critical trials, images of a known object and a novel object (e.g., a ball and a nameless artifact constructed in the laboratory) appeared on two computer screens and a voice asked children to “point at the _____ [e.g., glark].” Following label onset, children were allowed only 3 s during which to infer the correct referent, point at it, and potentially store this new word-object mapping. In a final posttest trial, all previously labeled novel objects appeared and children were asked to point to one of them (e.g., “Can you find the glark?”). To succeed, children needed to have initially mapped the novel labels correctly and retained these mappings over the course of the study. Despite the difficult demands of the current task, children successfully identified the target object on the retention trial. We conclude that 2-year-olds are able to fast map novel nouns during a brief single exposure under ambiguous labeling conditions.     

Novel labels support 10-month-olds’ attention to novel objects

What is the source of the mutual exclusivity bias whereby infants map novel labels onto novel objects? In an intermodal preferential looking task, we found that novel labels support 10-month-olds’ attention to a novel object over a familiar object. In contrast, familiar labels and a neutral phrase gradually reduced attention to a novel object. Markman (1989, 1990) argued that infants must recall the name of a familiar object to exclude it as the referent of a novel label. We argue that 10-month-olds’ attention is guided by the novelty of objects and labels rather than knowledge of the names for familiar objects. Mutual exclusivity, as a language-specific bias, might emerge from a more general constraint on attention and learning.     

Preschoolers trust particular informants when learning new names and new morphological forms

Across three studies, we investigated whether 4‐year‐olds would trust a previously reliable informant when learning novel morphological forms. In Experiment 1, children (N= 16) were presented with two informants: one who correctly named familiar objects and another who named them incorrectly. Children were invited to turn to these informants when learning novel labels and morphological forms. The majority of children chose the previously correct labeller when learning novel label and morphology. In Experiment 2, children (N= 16) were presented with an informant who used familiar plurals correctly and one who used them incorrectly. Children chose the previously correct morphologist when learning novel labels and past tense forms. Thus, children track both semantic and morphological accuracy. In Experiment 3, some children (N= 16) were presented with two informants who differed in naming accuracy, whereas others (N= 16) were presented with two informants who differed in morphological accuracy. To forestall any risk of experimenter cuing, one experimenter blind to the training children had received, tested children with novel labels and morphology. The results replicated those of Experiments 1 and 2. Implications for how children's trust in an informant might play a role in their acquisition of morphological forms are discussed.     

The development of a word-learning strategy

Two studies investigated young infants' use of the word-learning principle Mutual Exclusivity. In Experiment 1, a linear relationship between age and performance was discovered. Seventeen-month-old infants successfully used Mutual Exclusivity to map novel labels to novel objects in a preferential looking paradigm. That is, when presented a familiar and a novel object (e.g. car and phototube) and asked to "look at the dax", 17-month-olds increased looking to the novel object (i.e. phototube) above baseline preference. On these trials, 16-month-olds were at chance. And, 14-month-olds systematically increased looking to the familiar object (i.e. car) in response to hearing the novel label "dax". Experiment 2 established that this increase in looking to the car was due solely to hearing the novel label "dax". Several possible interpretations of the surprising form of failure at 14 months are discussed.     

The role of gaze direction and mutual exclusivity in guiding 24‐month‐olds' word mappings

In these studies, we examined how a default assumption about word meaning, the mutual exclusivity assumption and an intentional cue, gaze direction, interacted to guide 24‐month‐olds' object‐word mappings. In Expt 1, when the experimenter's gaze was consistent with the mutual exclusivity assumption, novel word mappings were facilitated. When the experimenter's eye‐gaze was in conflict with the mutual exclusivity cue, children demonstrated a tendency to rely on the mutual exclusivity assumption rather than follow the experimenter's gaze to map the label to the object. In Expt 2, children relied on the experimenter's gaze direction to successfully map both a first label to a novel object and a second label to a familiar object. Moreover, infants mapped second labels to familiar objects to the same degree that they mapped first labels to novel objects. These findings are discussed with regard to children's use of convergent and divergent cues in indirect word mapping contexts.     

Clarifying the role of shape in children's taxonomic assumption.

When asked to find a new referent of a novel label children tend to ignore thematic relations (e.g., the relation between a spider and its web) and focus instead on taxonomic relations (e.g., the relation between a spider and a snake). The precise nature of children's taxonomic assumption has not been clear, however. One possibility is that the taxonomic assumption reduces to a "similar-shape rule": perhaps children tend to select objects of the same taxonomic kind when asked to extend new labels simply because these objects are more similar in shape than objects which are only thematically related. Sixty children between 3 and 5 years of age participated in three studies which examined children's attention to thematic relations, similarity of shape, and taxonomic relations when extending novel object labels. The findings indicated that shape has some primacy in children's expectations about object label reference, yet when shape is not available as a guide, children also take taxonomic kind into consideration when searching for new referents of novel labels. Thus children make use of a relatively rich and somewhat varied set of expectations to guide their inferences about object label reference.     

Use of the mutual exclusivity assumption by young word learners

A critical question about early word learning is whether word learning constraints such as mutual exclusivity exist and foster early language acquisition. It is well established that children will map a novel label to a novel rather than a familiar object. Evidence for the role of mutual exclusivity in such indirect word learning has been questioned because: (1) it comes mostly from 2 and 3-year-olds and (2) the findings might be accounted for, not by children avoiding second labels, but by the novel object which creates a lexical gap children are motivated to fill. Three studies addressed these concerns by having only a familiar object visible. Fifteen to seventeen and 18-20-month-olds were selected to straddle the vocabulary spurt. In Study 1, babies saw a familiar object and an opaque bucket as a location to search. Study 2 handed babies the familiar object to play with. Study 3 eliminated an obvious location to search. On the whole, babies at both ages resisted second labels for objects and, with some qualifications, tended to search for a better referent for the novel label. Thus mutual exclusivity is in place before the onset of the naming explosion. The findings demonstrate that lexical constraints enable babies to learn words even under non-optimal conditions--when speakers are not clear and referents are not visible. The results are discussed in relation to an alternative social-pragmatic account.     

Learning words: children disregard some pragmatic information that conflicts with mutual exclusivity

Children tend to infer that when a speaker uses a new label, the label refers to an unlabeled object rather than one they already know the label for. Does this inference reflect a default assumption that words are mutually exclusive? Or does it instead reflect the result of a pragmatic reasoning process about what the speaker intended? In two studies, we distinguish between these possibilities. Preschoolers watched as a speaker pointed toward (Study 1) or looked at (Study 2) a familiar object while requesting the referent for a new word (e.g. ‘Can you give me the blicket?’). In both studies, despite the speaker's unambiguous behavioral cue indicating an intent to refer to a familiar object, children inferred that the novel label referred to an unfamiliar object. These results suggest that children expect words to be mutually exclusive even when a speaker provides some kinds of pragmatic evidence to the contrary.     

Words,shape, visual search and visual working memory in 3‐year‐old children

Do words cue children's visual attention, and if so, what are the relevant mechanisms? Across four experiments, 3‐year‐old children (N = 163) were tested in visual search tasks in which targets were cued with only a visual preview versus a visual preview and a spoken name. The experiments were designed to determine whether labels facilitated search times and to examine one route through which labels could have their effect: By influencing the visual working memory representation of the target. The targets and distractors were pictures of instances of basic‐level known categories and the labels were the common name for the target category. We predicted that the label would enhance the visual working memory representation of the target object, guiding attention to objects that better matched the target representation. Experiments 1 and 2 used conjunctive search tasks, and Experiment 3 varied shape discriminability between targets and distractors. Experiment 4 compared the effects of labels to repeated presentations of the visual target, which should also influence the working memory representation of the target. The overall pattern fits contemporary theories of how the contents of visual working memory interact with visual search and attention, and shows that even in very young children heard words affect the processing of visual information.     

Children's avoidance of lexical overlap: a pragmatic account

Children tend to choose an unfamiliar object rather than a familiar one when asked to find the referent of a novel name. This response has been taken as evidence for the operation of certain lexical constraints in children's inferences of word meanings. The present studies test an alternative--pragmatic--explanation of this phenomenon among 3-year-olds. In Study 1 children responded to a request for the referent of a novel label in the same way that they responded to a request for the referent of a novel fact. Study 2 intimated that children assume that labels are common knowledge among members of the same language community. Study 3 demonstrated that shared knowledge between a speaker and listener plays a decisive role in how children interpret a speaker's request. The findings suggest that 3-year-olds' avoidance of lexical overlap is not unique to naming and may derive from children's sensitivity to speakers' communicative intentions.     

Two-year-olds' recognition of hierarchies: Evidence from their interpretation of the semantic relation between object labels

The present studies investigated 2-year-olds' recognition of hierarchies by examining under various conditions the relative frequency with which children interpreted novel and familiar labels for objects as mutually exclusive. Two-year-olds were taught novel labels in one of three ways: (a) inclusive input: “[novel label] is a kind of [familiar label]”; (b) exclusive input: “[novel label] is not a [familiar label]”; or (c) (Study 2) no relational input. The referents of the novel and familiar labels were taxonomically either: (a) strongly related (e.g., a fighter airplane and a passenger airplane), or (b) weakly related (e.g., a paint brush and a toothbrush). Children were less likely to interpret the labels as picking out mutually exclusive categories when: (a) the labels were introduced with the inclusive input; and (b) the referents of the labels were taxonomically strongly related. This modulation of mutual exclusivity interpretations in response to the various hierarchical relations instantiated in the stimuli and input provides evidence for 2-year-olds' emerging capacity to recognize hierarchical relations.     

Pragmatics aid referent disambiguation and word learning in young children and adults

How do children succeed in learning a word? Research has shown robustly that, in ambiguous labeling situations, young children assume novel labels to refer to unfamiliar rather than familiar objects. However, ongoing debates center on the underlying mechanism: Is this behavior based on lexical constraints, guided by pragmatic reasoning, or simply driven by children's attraction to novelty? Additionally, recent research has questioned whether children's disambiguation leads to long-term learning or rather indicates an attentional shift in the moment of the conversation. Thus, we conducted a pre-registered online study with 2- and 3-year-olds and adults. Participants were presented with unknown objects as potential referents for a novel word. Across conditions, we manipulated whether the only difference between both objects was their relative novelty to the participant or whether, in addition, participants were provided with pragmatic information that indicated which object the speaker referred to. We tested participants’ immediate referent selection and their retention after 5 min. Results revealed that when given common ground information both age groups inferred the correct referent with high success and enhanced behavioral certainty. Without this information, object novelty alone did not guide their selection. After 5 min, adults remembered their previous selections above chance in both conditions, while children only showed reliable learning in the pragmatic condition. The pattern of results indicates how pragmatics may aid referent disambiguation and learning in both adults and young children. From early ontogeny on, children's social-cognitive understanding may guide their communicative interactions and support their language acquisition.

Research Highlights

• We tested how 2-3-year-olds and adults resolve referential ambiguity without any lexical cues.
• In the pragmatic context both age groups disambiguated novel word-object-mappings, while object novelty alone did not guide their referent selection.
• In the pragmatic context, children also showed increased certainty in disambiguation and retained new word-object-mappings over time.
• These findings contribute to the ongoing debate on whether children learn words on the basis of domain-specific constraints, lower-level associative mechanisms, or pragmatic inferences.

     

Compliance, conversion, and category induction

When children hear an object referred to with a label that is moderately discrepant from its appearance, they frequently make inferences about that object consistent with the label rather than its appearance. We asked whether 3-year-olds actually believe these unexpected labels (i.e., conversion) or whether their inferences simply reflect a desire to comply with the considerable experimental demands of the induction task (i.e., compliance). Specifically, we asked how likely children would be to pass an unexpected label on to another person who had not been present during the labeling event. Results showed that children who used an unexpected label as the basis for inference passed that label on to another person about as often as they could remember it. This suggests that children’s label-based inferences do reflect conversion rather than mere compliance.     

Looks Aren't Everything: 24-Month-Olds' Willingness to Accept Unexpected Labels

A label can efficiently convey nonobvious information about category membership, but this information can sometimes conflict with one's own expectations. Two studies explored whether 24-month-olds (N = 56) would be willing to accept a category label indicating that an animal (Study 1) or artifact (Study 2) that looked like a member of one familiar category was actually a member of a different familiar category. Results showed that children were receptive to these unexpected labels and used them as the basis for inference. These findings indicate that linguistic information can lead even toddlers to “disbelieve their eyes.”     

Evidence for a form of mutual exclusivity during label acquisition by grey parrots (Psittacus erithacus)?

The authors present context-dependent evidence for a form of mutual exclusivity during label learning by Grey parrots (Psittacus erithacus). For human children, mutual exclusivity refers to their assumption during early word learning that an object has one and only one label. Along with the whole-object assumption (that a label likely refers to an entire object rather than some partial aspect), mutual exclusivity is thought to guide children in initial label acquisition. It may also help children overcome the whole-object assumption by helping them interpret a novel word as something other than an object label, but for young children, any second label for an object can initially be more difficult to acquire than the first. The authors show that Grey parrots quickly learn object labels for items, then have considerable difficulty learning to use color labels with respect to a previously labeled item unless specifically taught to use a color and object label as a pair.     

Get by With a Little Help From a Word: Multimodal Input Facilitates 26-Month-Olds' Ability to Map and Generalize Arbitrary Gestural Labels

In the early stages of word learning, children demonstrate considerable flexibility in the type of symbols they will accept as object labels. However, around the 2nd year, as children continue to gain language experience, they become focused on more conventional symbols (e.g., words) as opposed to less conventional symbols (e.g., gestures). During this period of symbolic narrowing, the degree to which children are able to learn other types of labels, such as arbitrary gestures, remains a topic of debate. Thus, the purpose of the current set of experiments was to determine whether a multimodal label (word + gesture) could facilitate 26-month-olds' ability to learn an arbitrary gestural label. We hypothesized that the multimodal label would exploit children's focus on words thereby increasing their willingness to interpret the gestural label. To test this hypothesis, we conducted two experiments. In Experiment 1, 26-month-olds were trained with a multimodal label (word + gesture) and tested on their ability to map and generalize both the arbitrary gesture and the multimodal label to familiar and novel objects. In Experiment 2, 26-month-olds were trained and tested with only the gestural label. The findings revealed that 26-month-olds are able to map and generalize an arbitrary gesture when it is presented multimodally with a word, but not when it is presented in isolation. Furthermore, children's ability to learn the gestural labels was positively related to their reported productive vocabulary, providing additional evidence that children's focus on words actually helped, not hindered, their gesture learning.     

Non-native language exposure promotes children’s willingness to accept labels in two languages

Bilingualism has been associated with a range of cognitive and language-related advantages, including the recognition that words can have different labels across languages. However, most previous research has failed to consider heterogeneity in the linguistic environments of children categorized as monolingual. Our study assessed the influence of non-native language experience on children’s acceptance of labels in 2 languages. In a continuous measure of language exposure, parents reported the number of hours during which their children heard non-English languages from different sources. English-speaking 5-year-olds (N = 73) were presented with novel labels in English and Spanish for unfamiliar objects and were asked to endorse either or both labels. Children with greater exposure to non-English languages were more likely than less-exposed children to endorse both the English and Spanish labels. The findings suggest that monolingual children’s willingness to learn non-native vocabulary can be enhanced by exposure to non-native languages.     

Children's ability to integrate class information

Coordination and integration of class information was examined using a multidimensional similarity judgment task in which four- and nine-year old children rated the similarity of pairs of stimuli sharing either one or two atribute values. Half the children at each age were assigned to an attention condition requiring they label relevant stimulus atributes before making their similarity ratings. The other children were in the nonattention condition, and rated similarity without labelling the attributes. The results indicated that four-year-olds in the attention condition and nine-year-olds in both conditions integrated class information in making their similarity judgments. Performance of the four-year-olds in the non-attention condition tended to improve across trials; they appeared to integrate class information on later trials.