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.

Object play in the everyday home environment generates rich opportunities for infant learning.

Infants everywhere engage with objects throughout the day, even if the objects of play differ across cultures. Indeed, object play is a universal context for learning. Yet, the characteristics of object play at home remain largely unexamined, especially in infants from non-English-speaking backgrounds. Through frame-by-frame video coding, we documented Hispanic infants' object interactions based on 1-2 h of naturalistic home observations. Infants interacted with a wide variety of toys and household objects in brief bouts that summed to ~60% of their time. As infants transition among objects, they serendipitously generate opportunities for learning that support development across domains.

Flexibility in action: Development of locomotion under overhead barriers.

Behavioral flexibility-the ability to tailor motor actions to changing body-environment relations-is critical for functional movement. Navigating the everyday environment requires the ability to generate a wide repertoire of actions, select the appropriate action for the current situation, and implement it quickly and accurately. We used a new, adjustable barrier paradigm to assess flexibility of motor actions in 20 17-month-old (eight girls, 12 boys) and 14 13-month-old (seven girls, eight boys) walking infants and a comparative sample of 14 adults (eight women, six men). Most participants were White, non-Hispanic, and middle class. Participants navigated under barriers normalized to their standing height (overhead, eye, chest, hip, and knee heights). Decreases in barrier height required lower postures for passage. Every participant altered their initial walking posture according to barrier height for every trial, and all but two 13-month-olds found solutions for passage. Compared to infants, adults displayed a wider variety of strategies (squat-walking, half-kneeling, etc.), found more appropriate solutions based on barrier height (ducked at eye height and low crawled at knee height), and implemented their solutions more quickly (within 4 s) and accurately (without bumping their heads against the barrier). Infants frequently crawled even when the barrier height did not warrant a low posture, displayed multiple postural shifts prior to passage and thus took longer to go, and often bumped their heads. Infants' improvements were related to age and walking experience. Thus, development of flexibility likely involves the contributions of multiple domains-motor, perception, and cognition-that facilitate strategy selection and implementation. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Joint engagement in the home environment is frequent, multimodal, timely, and structured.

Infants develop in a social context, surrounded by knowledgeable caregivers who scaffold learning through shared engagement with objects. However, researchers have typically examined joint engagement in structured tasks, where caregivers sit near infants and display frequent, prompt, and multimodal behaviors around the objects of infant action. Which features of joint engagement generalize to the real-world? Despite the importance of joint engagement for infant learning, critical assumptions around joint engagement in everyday interaction remain unexamined. We investigated behavioral and temporal features of joint engagement in the home environment, where objects for play abound and dyad proximity fluctuates. Infant manual actions, mother manual and verbal behaviors, and dyad proximity were coded frame-by-frame from 2-h naturalistic recordings of 13- to 23-month-old infants and their mothers (N = 38). Infants experienced rich, highly structured, multimodal mother input around the objects of their actions. Specifically, joint engagement occurred within seconds of infant action and was amplified in the context of interpersonal proximity. Findings validate laboratory-based research on characteristics of joint engagement while highlighting unique properties around the role of mother-infant proximity and temporal structuring of caregiver input over extended time frames. Implications for the social contexts that support infant learning and development are discussed.

Infant exuberant object play at home: Immense amounts of time-distributed, variable practice.

Object play yields enormous benefits for infant development. However, little is known about natural play at home where most object interactions occur. We conducted frame-by-frame video analyses of spontaneous activity in two 2-h home visits with 13-month-old crawling infants and 13-, 18-, and 23-month-old walking infants (N = 40; 21 boys; 75% White). Regardless of age, for every infant and time scale, across 10,015 object bouts, object interactions were short (median = 9.8 s) and varied (transitions among dozens of toys and non-toys) but consumed most of infants' time. We suggest that infant exuberant object play-immense amounts of brief, time-distributed, variable interactions with objects-may be conducive to learning object properties and functions, motor skill acquisition, and growth in cognitive, social, and language domains.

(Hyper)active Data Curation: A Video Case Study from Behavioral Science.

Video data are uniquely suited for research reuse and for documenting research methods and findings. However, curation of video data is a serious hurdle for researchers in the social and behavioral sciences, where behavioral video data are obtained session by session and data sharing is not the norm. To eliminate the onerous burden of post hoc curation at the time of publication (or later), we describe best practices in active data curation-where data are curated and uploaded immediately after each data collection to allow instantaneous sharing with one button press at any time. Indeed, we recommend that researchers adopt "hyperactive" data curation where they openly share every step of their research process. The necessary infrastructure and tools are provided by Databrary-a secure, web-based data library designed for active curation and sharing of personally identifiable video data and associated metadata. We provide a case study of hyperactive curation of video data from the Play and Learning Across a Year (PLAY) project, where dozens of researchers developed a common protocol to collect, annotate, and actively curate video data of infants and mothers during natural activity in their homes at research sites across North America. PLAY relies on scalable standardized workflows to facilitate collaborative research, assure data quality, and prepare the corpus for sharing and reuse throughout the entire research process.

Postural, Visual, and Manual Coordination in the Development of Prehension.

We investigated the real-time cascade of postural, visual, and manual actions for object prehension in 38 6- to 12-month-old infants (all independent sitters) and eight adults. Participants' task was to retrieve a target as they spun past it at different speeds on a motorized chair. A head-mounted eye tracker recorded visual actions and video captured postural and manual actions. Prehension played out in a coordinated sequence of postural-visual-manual behaviors starting with turning the head and trunk to bring the toy into view, which in turn instigated the start of the reach. Visually fixating the toy to locate its position guided the hand for toy contact and retrieval. Prehension performance decreased at faster speeds, but quick planning and implementation of actions predicted better performance.