Comparing apples to manzanas and oranges to naranjas: A new measure of English-Spanish vocabulary for dual language learners.

The valid assessment of vocabulary development in dual-language-learning infants is critical to developmental science. We developed the Dual Language Learners English-Spanish (DLL-ES) Inventories to measure vocabularies of U.S. English-Spanish DLLs. The inventories provide translation equivalents for all Spanish and English items on Communicative Development Inventory (CDI) short forms; extended inventories based on CDI long forms; and Spanish language-variety options. Item-Response Theory analyses applied to Wordbank and Web-CDI data (n = 2603, 12-18 months; n = 6722, 16-36 months; half female; 1% Asian, 3% Black, 2% Hispanic, 30% White, 64% unknown) showed near-perfect associations between DLL-ES and CDI long-form scores. Interviews with 10 Hispanic mothers of 18- to 24-month-olds (2 White, 1 Black, 7 multi-racial; 6 female) provide a proof of concept for the value of the DLL-ES for assessing the vocabularies of DLLs.

A Novel Approach to Assessing Infant and Child Mental Rotation.

Mental rotation is a critically important, early developing spatial skill that is related to other spatial cognitive abilities. Understanding the early development of this skill, however, requires a developmentally appropriate assessment that can be used with infants, toddlers, and young children. We present here a new eye-tracking task that uses a staircase procedure to assess mental rotation in 12-, 24-, and 36-month-old children (N = 41). To ensure that all children understood the task, the session began with training and practice, in which the children learned to fixate which of two houses a giraffe, facing either left or right, would approach. The adaptive two-up, one-down staircase procedure assessed the children's ability to fixate the correct house when the giraffe was rotated in 30° (up) or 15° (down) increments. The procedure was successful, with most children showing evidence of mental rotation. In addition, the children were less likely to succeed as the angle of rotation increased, and the older children succeeded at higher angles of rotation than the younger children, replicating previous findings with other procedures. The present study contributes a new paradigm that can assess the development of mental rotation in young children and holds promise for yielding insights into individual differences in mental rotation.

An investigation of mental rotation in infancy using change detection.

Two experiments were conducted to examine mental rotation in 6- to 12-month-old infants (N = 166) using a change detection task. These experiments were replications of Lauer and Lourenco (Lauer et al., 2015; Lauer & Lourenco, 2016), using identical stimuli and variations of their procedure, including an exact replication conducted in a laboratory setting (Experiment 1), and an online assessment using Lookit (Scott et al.,2017; Scott & Schulz, 2017) (Experiment 2). Both experiments failed to replicate the results of the original study; in neither experiment did infants' behavior provide evidence that they mentally rotated the object. Results are discussed in terms of the robustness of mental rotation in infancy and about limits in our experimental procedures for uncovering perceptual and cognitive abilities in infants.

Natural Variability in Parent-Child Puzzle Play at Home.

Here, we observed 3- to 4-year-old children (N=31) and their parents playing with puzzles at home during a zoom session to provide insight into the variability of the kinds of puzzles children have in their home, and the variability in how children and their parents play with spatial toys. We observed a large amount of variability in both children and parents' behaviors, and in the puzzles they selected. Further, we found relations between parents' and children's behaviors. For example, parents provided more scaffolding behaviors for younger children and parents' persistence-focused language was related to more child attempts after failure. Altogether, the present work shows how using methods of observing children at a distance, we can gain insight into the environment in which they are developing. The results are discussed in terms of how variability in spatial toys and spatial play during naturalistic interactions can help us contextualize the conclusions we draw from lab-based studies.

From Lab to Zoom: Adapting Training Study Methodologies to Remote Conditions.

Training studies extend developmental research beyond single-session lab tasks by evaluating how particular experiences influence developmental changes over time. This methodology is highly interactive and typically requires experimenters to have easy, in-person access to large groups of children. When constraints were placed on in-person data collection due to the COVID-19 pandemic, administering this study format in the conventional manner became unfeasible. To implement this type of research under these new circumstances, we devised an alternative approach that enabled us to conduct a live, multi-session training study using a diverse array of activities through an online interface, a task necessitating creative problem solving, since most existing remote methodologies either rely on unsupervised methods or have been limited to single sessions and restricted to a limited number of tasks. The current paper describes the technological and practical adaptations implemented in our online training study of 118 4- and 5-year-old children from a geographically diverse sample. An experimenter interacted with the children once a week for 5 weeks over Zoom. The first and final sessions were dedicated to collecting baseline and post-test measures, while the intermediate 3 weeks were structured as a training designed to teach children specific spatial-cognitive and visuo-motor integration skills. The assessments and training contained image-filled spatial tasks that experimenters shared on their screen, a series of hands-on activities that children completed on their own device and on paper while following experimenters' on-screen demonstrations, and tasks requiring verbal indicators from the parent about their child's response. The remote nature of the study presented a unique set of benefits and limitations that has the potential to inform future virtual child research, as our study used remote behavioral methods to test spatial and visuo-motor integration skills that have typically only been assessed in lab settings. Results are discussed in relation to in-lab studies to establish the viability of testing these skills virtually. As our design entailed continual management of communication issues among researchers, parents, and child participants, strategies for streamlined researcher training, diverse online recruitment, and stimuli creation are also discussed.

Children's exposure to spatial language promotes their spatial thinking.

Does spatial language contribute to the growth of preschool children's spatial skills? Four-year-old children (N = 50) were randomly assigned to a play-only (n = 24) or a spatial-language and play condition (n = 26). Their mental rotation and spatial vocabulary were assessed at baseline and several days after 5 play sessions. Children in the spatial-language condition scored higher at posttest on a mental rotation task than those in the play-only condition. The amount and diversity of experimenter spatial language during the play sessions accounted for a significant amount of the variance on children's posttest mental rotation. Significant gains in mental rotation were replicated in a second study (N = 34) with a broader range of play activities and with children enrolled in Head Start. These results show that the facilitative effects of spatial language on spatial cognition are not restricted to the context in which the spatial language is provided. In particular, 4-year-old children's experience with spatial language during play can transfer to promote their mental rotation. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Above and Beyond Objects: The Development of Infants' Spatial Concepts.

Early in development infants form categorical representations of small-scale spatial relations, such as left vs right and above vs below. This spatial skill allows infants to experience coherence in the layout of the objects in their environment and to note the equivalence of a spatial relation across changes in objects. Comparisons across studies of infant spatial categorization offer insight into the processes that contribute to the development of this skill. Rather than viewing contrasting results across studies as contradictory, identifying how infant spatial categorization tasks recruit distinct processes can not only reconcile findings but also yield insight into the starting points, development, and emerging nature of infants' representations of spatial relations. Also, situating infants' spatial categorization in the context of advances in nonspatial domains may reveal synergistic relations among these domains, particularly in relation to advances in infants' manipulative play with objects and their acquisition of spatial language. A central argument is that broadening the study of infants' spatial categorization may yield further insights into the nature of early spatial concepts and the processes that promote their development.

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.

The impact of object type on the spatial analogies in Korean preschoolers.

We tested young children's spatial reasoning in a match-to-sample task, manipulating the objects in the task (abstract geometric shapes, line drawings of realistic objects, or both). Korean 4- and 5-year-old children (N=161) generalized the target spatial configuration (i.e., on, in, above) more easily when the sample used geometric shapes and the choices used realistic objects than the reverse (i.e., realistic-object sample to geometric-shape choices). With within-type stimuli (i.e., sample and choices were both geometric shapes or both realistic objects), 5-year-old, but not 4-year-old, children generalized the spatial relations more easily with geometric shapes than realistic objects. In addition, children who knew more locative terms (e.g., "in", "on") performed better on the task, suggesting a link to children's spatial vocabulary. The results demonstrate an advantage of geometric shapes over realistic objects in facilitating young children's performance on a match-to-sample spatial reasoning task.

Getting some space: Infants' and caregivers' containment and support spatial constructions during play.

Using a cross-sectional design, we examined the containment and support spatial constructions infants spontaneously create and those they observe when playing with a nesting toy. Infants (N=76) of 8, 13, or 18months played alone for 2min and then played with a caregiver for another 2min. At 8months, infants created few relations; at 13months, they inserted objects, resulting in containment, and stacked objects, resulting in support; at 18months, they created more than three times more containment relations than support relations, a result replicated in a second study. In contrast, caregivers created more support relations than containment relations, regardless of infant age, but labeled containment more than support. The results highlight differential exposure to containment and support in infant solitary and dyadic play. By 18months, infants gain greater firsthand experience with containment, a relation that is further reinforced by caregiver labeling.

Plain or decorated? Object visual features matter in infant spatial categorization.

The current study investigated infant spatial categorization of a support relation across differences in the perceptual features of the objects. Infants of 8 and 14 months (N = 67) were habituated to dynamic support events with objects that were plain and monochromatic or those that were embellished with decorations (e.g., polka dots, feathers). Infants were then tested with events that presented a novel pair of objects, a novel spatial relation (i.e., containment), or both. Infants, particularly those of 8 months, formed an abstract categorical representation of a support relation when habituated with the decorated objects but not the plain objects. The results suggest that the perceptual features of objects can facilitate infants' categorization of spatial relations, at least in some learning settings and especially with younger infants.

English- and Mandarin-learning infants' discrimination of actions and objects in dynamic events.

The present studies examined the role of linguistic experience in directing English and Mandarin learners' attention to aspects of a visual scene. Specifically, they asked whether young language learners in these 2 cultures attend to differential aspects of a word-learning situation. Two groups of English and Mandarin learners, 6-8-month-olds (n = 65) and 17-19-month-olds (n = 91), participated in 2 studies, based on a habituation paradigm, designed to test infants' discrimination between actions and objects in dynamic events. In Study 1, these stimuli were presented in silence, whereas in Study 2, a verbal label accompanied videos. Results showed that 6-8-month-olds could discriminate action changes but not object changes, whereas 17-19-month-olds could discriminate both types of changes. However, there were only very subtle cross-linguistic differences in these patterns when the scenes were presented together with a verbal label. These findings show strong evidence for universal developmental trends in attention, with somewhat weaker evidence that the differences in the types of words Mandarin- versus English-learning children produce or are exposed to affect attention to different aspects of a scene in the first 2 years of life.

Pedagogical cues encourage toddlers' transmission of recently demonstrated functions to unfamiliar adults.

Young children use pedagogical cues as a signal that others' actions are social or cultural conventions. Here we show that children selectively transmit (enact in a new social situation) causal functions demonstrated pedagogically, even when they have learned and can produce alternative functions as well. Two-year-olds saw two novel toys, each with two functions. One experimenter demonstrated one function using pedagogical cues (eye contact and child-directed speech) and a second experimenter demonstrated the alternative function using intentional actions towards the object, but without pedagogical cues. Children imitated both functions at equal rates initially, indicating equal causal learning from both types of demonstration. However, they were significantly more likely to enact the pedagogical function for a new adult not present during the initial demonstrations. These results indicate that pedagogical cues influence children's transmission of information, perhaps playing a role in the dissemination of cultural conventions from a young age.

Infant sensitivity to speaker and language in learning a second label.

Two experiments examined when monolingual, English-learning 19-month-old infants learn a second object label. Two experimenters sat together. One labeled a novel object with one novel label, whereas the other labeled the same object with a different label in either the same or a different language. Infants were tested on their comprehension of each label immediately following its presentation. Infants mapped the first label at above chance levels, but they did so with the second label only when requested by the speaker who provided it (Experiment 1) or when the second experimenter labeled the object in a different language (Experiment 2). These results show that 19-month-olds learn second object labels but do not readily generalize them across speakers of the same language. The results highlight how speaker and language spoken guide infants' acceptance of second labels, supporting sociopragmatic views of word learning.

Developmental changes in infant spatial categorization: when more is best and when less is enough.

Two experiments examined infants' ability to form a spatial category when habituated to few (only 2) or many (6) exemplars of a spatial relation. Sixty-four infants of 10 months and 64 infants of 14 months were habituated to dynamic events in which a toy was placed in a consistent spatial relation (in or on) to a referent object. At 10 months, infants formed a spatial category (looking longer at an unfamiliar than familiarized spatial relation) only when habituated to 6 exemplars. At 14 months, infants formed the spatial category regardless of the number of habituation exemplars. The results highlight developmental changes in infant spatial categorization and show that increasing exemplar number facilitates this ability in infants of 10 months.

Learning to form a spatial category of tight-fit relations: how experience with a label can give a boost.

Two experiments explored the ability of 18-month-old infants to form an abstract categorical representation of tight-fit spatial relations in a visual habituation task. In Experiment 1, infants formed an abstract spatial category when hearing a familiar word (tight) during habituation but not when viewing the events in silence or when hearing a novel word. In Experiment 2, infants were given experience viewing and producing tight-fit relations while an experimenter labeled them with a novel word. Following this experience, infants formed the tight-fit spatial category in the visual habituation task, particularly when hearing the novel word again during habituation. Results suggest that even brief experience with a label and tight-fit relations can aid infants in forming an abstract categorical representation of tight-fit relations.

The Development of Specialized Processing of Own-Race Faces in Infancy.

In this study, we examined developmental changes in infants' processing of own- versus other-race faces. Caucasian American 8-month-olds (Experiment 1) and 4-month-olds (Experiment 2) were tested in a habituation-switch procedure designed to assess holistic (attending to the relationship between internal and external features of the face) versus featural (attending to individual features of the face) processing of faces. Eight-month-olds demonstrated holistic processing of upright own-race (Caucasian) faces, but featural processing of upright other-race (African) faces. Inverted faces were processed featurally, regardless of ethnicity. Four-month-olds, however, demonstrated holistic processing of both Caucasian and African upright faces. These results demonstrate that infants' processing of own- versus other-race faces becomes specialized between 4 and 8 months.

Do novel words facilitate 18-month-olds' spatial categorization?

Eighteen-month-olds' spatial categorization was tested when hearing a novel spatial word. Infants formed an abstract categorical representation of support (i.e., placing 1 object on another) when hearing a novel spatial particle during habituation but not when viewing the events in silence. Infants with a productive spatial vocabulary did not discriminate the support relation when hearing the same novel word as a count noun. However, infants who were not yet producing spatial words did attend to the support relation when presented with the novel count noun. The results indicate that 18-month-olds can use a novel particle (possibly assisted by a familiar verb) to facilitate their spatial categorization but that the specificity of this effect varies with infants' acquisition of spatial language.

Discriminating signs: perceptual precursors to acquiring a visual-gestural language.

We tested hearing 6- and 10-month-olds' ability to discriminate among three American Sign Language (ASL) parameters (location, handshape, and movement) as well as a grammatical marker (facial expression). ASL-naïve infants were habituated to a signer articulating a two-handed symmetrical sign in neutral space. During test, infants viewed novel two-handed signs that varied in only one parameter or in facial expression. Infants detected changes in the signer's facial expression and in the location of the sign but provided no evidence of detecting the changes in handshape or movement. These findings are consistent with children's production errors in ASL and reveal that infants can distinguish among some parameters of ASL more easily than others.

Getting there faster: 18- and 24-month-old infants' use of function words to determine reference.

Infants of 18 and 24 months acquiring English were tested in a preferential looking task on their ability to detect ungrammaticalities caused by manipulating a single function word in sentences. Infants heard grammatical sentences in which the determiner the preceded a target noun, as well as three ungrammatical conditions in which the was either dropped, replaced by a nonsense function word (el), or replaced by an alternate English function word (and). Both the 18- and 24-month-old infants oriented faster and more accurately to a visual target following grammatical sentences. The results suggest that by 18 months of age, infants use their knowledge of determiners in sentence computation and in establishing reference.