Toddlers can adaptively change how they categorize: same objects, same session, two different categorical distinctions

A protocol for social interactive assessment of infant attention set-shifting between 12-24 months of age

This protocol describes an adaptation of a classic sequential touching object categorisation task to assess infant attention set-shifting, suitable for ages 12-24 months. The task is conducted in a social interactive context with a parent, who scaffolds their infants' attention shift from high-salience to low-salience dimensional properties of objects (e.g., shape vs material). This task is adapted from Ellis and Oakes (2006), where 14 month-old infants were able to flexibly attend to both shape and material. In this paper, we present a methodological innovation which permits the direct measurement of the effect of parent-child interactions on an early developing executive function skill. This novel social interactive protocol permits direct assessment of the effect of parent-child interaction on an early executive function skill, attention set-shifting.•The parental role is to scaffold a shift in their child's attention from a high salient (e.g. shape) to a low-salient (e.g. material) dimension of the stimulus set.•The protocol is suitable for infants aged between 12 and 24 months.

The Design and Development of Instrumented Toys for the Assessment of Infant Cognitive Flexibility

The first years of an infant's life represent a sensitive period for neurodevelopment where one can see the emergence of nascent forms of executive function (EF), which are required to support complex cognition. Few tests exist for measuring EF during infancy, and the available tests require painstaking manual coding of infant behaviour. In modern clinical and research practice, human coders collect data on EF performance by manually labelling video recordings of infant behaviour during toy or social interaction. Besides being extremely time-consuming, video annotation is known to be rater-dependent and subjective. To address these issues, starting from existing cognitive flexibility research protocols, we developed a set of instrumented toys to serve as a new type of task instrumentation and data collection tool suitable for infant use. A commercially available device comprising a barometer and an inertial measurement unit (IMU) embedded in a 3D-printed lattice structure was used to detect when and how the infant interacts with the toy. The data collected using the instrumented toys provided a rich dataset that described the sequence of toy interaction and individual toy interaction patterns, from which EF-relevant aspects of infant cognition can be inferred. Such a tool could provide an objective, reliable, and scalable method of collecting early developmental data in socially interactive contexts.

Play with Mom: Insights into Regulatory Processes at Work during Baseline and Parent-infant Play

Frontal alpha asymmetry (FAA) is a neural correlate of approach and avoidance motivational processes. This study examined the shift in FAA from baseline to play, associations to parent-reported regulatory abilities, and parent and infant behaviors during play. Infants exhibited greater left frontal alpha activity (more approach) during baseline relative to play. Shifts in FAA toward greater left frontal alpha activity (more approach) from baseline to play were associated with parent ratings of infants' regulatory behaviors and object exploration exhibited during play. These results highlight ongoing regulatory processes involved in positively valenced tasks typical in infants' daily life.

What Develops in Infants' Spatial Categorization? Korean Infants' Categorization of Containment and Tight-Fit Relations

Korean-learning infants' categorization of two spatial categories, one consistent and one inconsistent with the Korean semantic category of "kkita," was examined. Infants of 10 months (n = 32) and 18 months (n = 49) were tested on their categorization of containment or tight fit spatial relations. At 10 months, infants only formed a category of containment, but at 18 months, their categorization of tight fit was significantly stronger than containment. The results suggest that Korean infants benefit from their language environment in forming a category of tight fit when the exemplars are perceptually diverse. In particular, infants' language environment may bolster their ability to generalize across diverse exemplars to form abstract categorical representations of spatial relations.

Individual and developmental differences in preschoolers' categorization biases and vocabulary across tasks

This study bridges prior research on young children's use of taxonomic versus thematic relations to categorize objects with prior research on their use of shared shape versus shared function to categorize artifacts. Specifically, this research examined associations in children's categorization tendencies across these two dichotomies, including assessments of individual differences, developmental trends, and vocabulary level. Preschoolers (3- to 5-year-olds) completed a receptive vocabulary assessment and two match-to-sample tasks: one pitting (superordinate) taxonomic and thematic relations against each other and one pitting shape and function similarity against each other. The results revealed individual and developmental variation in children's cross-task categorization biases, with a predominant tendency to focus on both thematic and function relations that became increasingly stronger with age. In 3- and 5-year-olds, function-based categorization was also positively associated with verb vocabulary. These findings demonstrate an emerging tendency to focus on relational information during the preschool years that, among other learning effects, may benefit verb acquisition. The results are discussed in terms of the real-time processing and developmental factors that might contribute to the development of strategies for learning about objects and categories during early childhood.

Categorization of two-dimensional and three-dimensional stimuli by 18-month-old infants

In two experiments, 18-month-old infants' categorization of 3D replicas and 2D photographs of the same animals and vehicles were compared to explore infants' flexibility in categorization across different object representations. Using a sequential touching procedure, infants completed one superordinate and two basic-level categorization tasks with 3D replicas, 2D cut out photographs, or 2D images on photo cubes ("2D cubes"). For superordinate sets, 3D replicas elicited longer mean run lengths than 2D cut outs, and 3D replicas elicited equivalent mean run lengths as 2D cubes. For basic-level sets, infants categorized high-contrast animal sets when presented with 3D replicas, but they failed to categorize any of the 2D photograph sets. Categorization processes appear to differ for 3D and 2D stimuli, and infants' discovery of object properties over time while manipulating objects may facilitate categorization, as least at the superordinate level. These findings are discussed in the context of infants' representation abilities and the integration of perception and action.

The Medium is the Message: Pictures and Objects Evoke Distinct Conceptual Relations in Parent-Child Conversations

An important developmental task is learning to organize experience by forming conceptual relations among entities (e.g., a lion and a snake can be linked because both are animals; a lion and a cage can be linked because the lion lives in the cage). We propose that representational medium (i.e., pictures vs. objects) plays an important role in influencing which relations children consider. Prior work has demonstrated that pictures more readily evoke broader categories, whereas objects more readily call attention to specific individuals. We therefore predicted that pictures would encourage taxonomic and shared-property relations, whereas objects would encourage thematic and slot-filler relations. We observed 32 mother-child dyads (M child ages = 2.9 and 4.3) playing with pictures and objects, and identified utterances in which they made taxonomic, thematic, shared-property, or slot-filler links between items. The results confirmed our predictions and thus support representational medium as an important factor that influences the conceptual relations expressed during dyadic conversations.

Development of categorization in infancy: advancing forward to the animate/inanimate level

Three experiments are reported on the development of object categorization skills during the second year of life. Experiment 1 examined whether 14- and 18-month-old infants were capable of performing categorization at the animate/inanimate (A/I) level using a sequential touching task. The 18-month-olds were significantly above chance and the 14-month-olds were also approaching above-chance significance, which is the highest level of inclusiveness ever tested in infancy. In Experiments 2 and 3, 14-month-old infants participated in a sequential touching task in which the part features of animate and inanimate objects were modified, allowing for a test of partonomic (i.e., legs and wheels) vs. taxonomic (i.e., animates and inanimates) categorization. Infants did not favor partonomic categorization, suggesting that A/I categories are not formed solely based on object parts such as legs and wheels.

Same items, different order: effects of temporal variability on infant categorization

How does variability between members of a category influence infants' category learning? We explore the impact of the order in which different items are sampled on category formation. Two groups of 10-months-olds were presented with a series of exemplars to be organized into a single category. In a low distance group, the order of presentation minimized the perceptual distance between consecutive exemplars. In a high distance group, the order of presentation maximized the distance between successive exemplars. At test, only infants in the High Distance condition reliably discriminated between the category prototype and an atypical exemplar. Hence, the order in which infants learnt about the exemplars impacted their categorization performance. Our findings demonstrate the importance of moment-to-moment variations in similarity during infants' category learning.

Get the story straight: contextual repetition promotes word learning from storybooks

Although shared storybook reading is a common activity believed to improve the language skills of preschool children, how children learn new vocabulary from such experiences has been largely neglected in the literature. The current study systematically explores the effects of repeatedly reading the same storybooks on both young children's fast and slow mapping abilities. Specially created storybooks were read to 3-year-old children three times during the course of 1 week. Each of the nine storybooks contained two novel name-object pairs. At each session, children either heard three different stories with the same two novel name-object pairs or the same story three times. Importantly, all children heard each novel name the same number of times. Both immediate recall and retention were tested with a four-alternative forced-choice task with pictures of the novel objects. Children who heard the same stories repeatedly were very accurate on both the immediate recall and retention tasks. In contrast, children who heard different stories were only accurate on immediate recall during the last two sessions and failed to learn any of the new words. Overall, then, we found a dramatic increase in children's ability to both recall and retain novel name-object associations encountered during shared storybook reading when they heard the same stories multiple times in succession. Results are discussed in terms of contextual cueing effects observed in other cognitive domains.