Search

Diversity and Representation in Infant Research: Barriers and bridges towards a globalized science of infant development Leher Singh, Alejandrina Cristia, Lana B. Karasik, Sarah J. Rajendra, and Lisa M. Oakes Author NoteLeher Singh, Department of Psychology, National University of Singapore, Singapore; Alejandrina Cristia, Laboratoire de Sciences Cognitives et Psycholinguistique, Département d’Etudes Cognitives, ENS, EHESS, CNRS, PSL University, Paris, France; Lana B. Karasik, Department of Psychology, College of Staten Island & Graduate Center, CUNY, Staten Island, New York, U.S.; Sarah J. Rajendra, Department of Psychology, National University of Singapore, Singapore; Lisa M. Oakes, Department of Psychology and Center for Mind and Brain, UC Davis, Davis, CA, U.S. Acknowledgments: This manuscript was supported by an ODPRT grant from the National University of Singapore to LS and by the J. S. McDonnell Foundation Understanding Human Cognition Scholar Award, European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (ExELang, Grant agreement No. 101001095) grant awards to AC, National Science Foundation Grant DLS-1349044 and Grant DLS-1528831to LBK.Address for correspondence: Correspondence concerning this article should be addressed to Leher Singh, Department of Psychology, National University of Singapore, 9 Arts Link, Singapore 117570 (psyls@nus.edu.sg) RUNNING HEAD: Global infant development AbstractPsychological researchers have become increasingly concerned with generalized accounts of human behavior based on participant representation. This concern is of particular relevance to infant research as findings from infant studies are often invoked to theorize broadly about the origins of human behavior. In this article, we examined participant diversity and representation in research published on infant development in four journals over the past decade. Sociodemographic data were coded for all articles reporting infant data published in Child Development, Developmental Science, Developmental Psychology, and Infancy between 2011 and 2022. Analyses of 1,682 empirical articles, sampling approximately 1 million participants, revealed consistent under-reporting of sociodemographic information. For studies that reported sociodemographic characteristics, there was an unwavering and strong skew towards White infants from North America/Western Europe over the decade sampled. To address a lack of diversity in infant studies and its scientific impact, a set of principles and practices are proposed to advance towards a more globally representative science.

Research on early language abilities, much like psychology more broadly, has focused almost exclusively on infants from English and Indo-European languages, thereby limiting understanding of the role of varying linguistic experience that supports language abilities. We underscore Kidd and Garcia’s call to expand, diversify, and globalize language research. Using examples from motor development in which universality has long been assumed, we argue that embracing a cross-cultural perspective enriches theories of development more broadly. We conclude with suggestions for future directions.

How infants are held or contained throughout the day shape infants' experiences, particularly around movement and exploration. In Tajikistan, caregivers use "gahvora" cradles, which severely restrict the body and limbs. The present study explored the variability and use of containment devices in U.S. and Tajik infants. Using time diaries, we compared 12-month-olds in the U.S. and Tajikistan on the types of containments used and time spent in them throughout the day. During the day, Tajik infants accumulated more time in gahvoras than infants in the U.S. spent in cribs, primarily used for sleep, suggesting gahvoras served other functions. Given the availability of other devices, U.S. infants' time was distributed in short yet frequent bouts across devices. Accumulated time in these containments matched accumulated time Tajik infants spent in gahvoras. Tajik infants accumulated more unrestricted time on the ground, which was distributed in prolonged bouts, than U.S. infants. Findings highlight differences in infants' everyday experiences during the developmental period when motor skills emerge. By embracing commonalities and exploring differences between cultures, this study offers insights into differences in infants' everyday experiences and opportunities for movement.

How do young children learn to use everyday artifacts-doorknobs, zippers, and so on-in the ways they were designed to be used? Although the designed actions of such objects seem obvious to adults, little is known about how young children learn the "hidden affordances" of everyday objects. We encouraged 115 11- to 37-month-old children to open 2 types of containers: circular jars with twist-off lids (Experiment 1) and rectangular Tupperware-style containers with pull-off lids (Experiment 2). We varied container size to examine effects of the body-environment fit on display of the designed action and successful implementation of the designed action. Results showed a developmental progression from nondesigned actions to performance of the designed twisting or pulling actions to successful implementation of the designed action. Nondesigned actions decreased with age as performance of the designed action increased. Successful implementation lagged behind performance of the designed action. That is, even after children appeared to know what to do, they were still unsuccessful in opening the container. Why? For twist-offs, very large lids were difficult to manipulate, and younger children often twisted to the right, or in both directions, and did not persist in consecutive turns to the left. Larger pull-off containers required new strategies to stabilize the base, such as holding the container against the tabletop or the chest. Findings provide insights into the body-environment factors that facilitate children's learning and implementation of the hidden affordances inherent in everyday artifacts. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

The study of motor development has traditionally focused on the timing and sequence of the acquisition of motor skills, such as sitting, crawling, or walking, over the first years of life. Because motor skills are directly observable, motor development serves as a useful exemplar for general principles of development. Current frameworks emphasize motor development in and as a context, such as how change in motor skill interacts with simultaneous change in other developmental domains, how the acquisition of new motor skills creates new opportunities for learning, and how the context in which motor development occurs shapes the course of development. For example, the onset of new motor skills changes the allocation of attentional resources, the quality of infants’ sleep, and available perceptual information. Reciprocally, contexts such as culturally specific parenting practices and individual differences in everyday experiences impact the timing and trajectory of new motor skills.

We examined mothers’ verbal responses to their crawling or walking infants’ object sharing (i.e., bids). Fifty mothers and their 13-month-olds were observed for 1 hour at home. Infants bid from a stationary position or they bid after carrying the object to their mothers. Mothers responded with affirmations (e.g., “thank you”), descriptions (“red box”), or action directives (“open it”). Infants’ locomotor status and the form of their bids predicted how mothers responded. Mothers of walkers responded with action directives more often than mothers of crawlers. Notably, differences in the responses of mothers of walkers versus those of crawlers were explained by differences in bid form between the two groups of infants. Walkers were more likely to engage in moving bids than crawlers, who typically shared objects from stationary positions. When crawlers displayed moving bids, their mothers offered action directives just as often as did mothers of walkers. Findings illustrate developmental cascades, wherein infants’ locomotor status affects how infants share objects with mothers, which in turn shapes mothers’ verbal responses.

How do infants decide what to do at the brink of a precipice? Infants could use two sources of information to guide their actions: perceptual information generated by their own exploratory activity and social information offered by their caregivers. The current study investigated the role of locomotor experience in using social information—both encouragement and discouragement—for descending drop-offs. Mothers of 30 infants (experienced 12-month-old crawlers, novice 12-month-old walkers, and experienced 18-month-old walkers) encouraged and discouraged descent on a gradation of drop-offs (safe “steps” and risky “cliffs”). Novice walkers descended more frequently than experienced crawlers and walkers and fell while attempting to walk over impossibly high cliffs. All infants showed evidence of integrating perceptual and social information, but locomotor experience affected infants’ use of social messages, especially on risky drop-offs. Experienced crawlers and walkers selectively deferred to social information when perceptual information is ambiguous. In contrast, novice walkers took mothers’ advice inconsistently and only at extreme drop-offs.

Motor development—traditionally described in terms of age-related stages—is typically studied in the laboratory with participants of Western European descent. Cross-cultural studies typically focus on group differences in age-related stages relative to Western norms. We adopted a less traditional approach: We observed 5-month-olds and their mothers from six cultural groups around the world during 1 hr at home while they engaged in natural daily activities. We examined group differences in infants’ sitting proficiency, everyday opportunities to practice sitting, the surfaces on which sitting took place, and mothers’ proximity to sitting infants. Infants had opportunities to practice sitting in varied contexts—including ground, infant chairs, and raised surfaces. Proficiency varied considerably within and between cultural groups: 64% of the sample sat only with support from mother or furniture and 36% sat independently. Some infants sat unsupported for 20+ min, in some cases so securely that mothers moved beyond arms’ reach of their infants even while infants sat on raised surfaces. Our observations of infant sitting across cultures provide new insights into the striking range of ability, varied opportunities for practice, and contextual factors that influence the proficiency of infant motor skills.

Carrying objects requires coordination of manual action and locomotion. This study investigated spontaneous carrying in 24 walkers who were 13 months old and 26 crawlers who were 13 months old during 1-hr, naturalistic observations in the infants' homes. Carrying was more common in walkers, but crawlers also carried objects. Typically, walkers carried objects in their hands, whereas crawlers multitasked by using their hands simultaneously for holding objects and supporting their bodies. Locomotor experience predicted frequency of carrying in both groups, suggesting that experienced crawlers and walkers perceive their increased abilities to handle objects while in motion. Despite additional biomechanical constraints imposed by holding an object, carrying may actually improve upright balance: Crawlers rarely fell while carrying an object, and walkers were more likely to fall without an object in hand than while carrying. Thus, without incurring an additional risk of falling, spontaneous carrying may provide infants with new avenues for combining locomotor and manual skills and for interacting with their environments.

Associations between infants’ transition to walking and object activities were examined. Fifty infants were observed longitudinally during home observations. At 11 months, all infants were crawlers; at 13 months, half became walkers. Over age, infants increased their total time with objects and frequency of sharing objects with mothers. Bidirectional influences between locomotion and object actions were found. Walking was associated with new forms of object behaviors: Walkers accessed distant objects, carried objects, and approached mothers to share objects; crawlers preferred objects close at hand and shared objects while remaining stationary. Earlier object activities predicted walking status: Crawlers who accessed distant objects, carried objects, and shared objects over distances at 11 months were more likely to walk by 13 months.

In uncertain situations such as descending challenging slopes, social signals from caregivers can provide infants with important information for guiding action. Previous work showed that 18-month-old walking infants use social information selectively, only when risk of falling is uncertain. Experiment 1 was designed to alter infants' region of uncertainty for walking down slopes. Slippery Teflon-soled shoes drastically impaired 18-month-olds' ability to walk down slopes compared with walking barefoot or in standard crepe-soled shoes, shifting the region of uncertainty to a shallower range of slopes. In Experiment 2, infants wore Teflon-soled shoes while walking down slopes as their mothers encouraged and discouraged them from walking. Infants relied on social information on shallow slopes, even at 0^o, where the probability of walking successfully was uncertain in the Teflon-soled shoes. Findings indicate that infants' use of social information is dynamically attuned to situational factors and the state of their current abilities.

As Iverson (this issue) points out, it is ironic that motor development has been relegated to peripheral ‘Cinderella’ status in developmental psychology. After all, for those researchers who view psychology as the study of behavior, motor development is the stuff of the science. All behaviors – walking, talking, looking, laughing, reaching, playing, sleeping, breathing – are motor behaviors. And for those researchers who view psychology as the study of mind, motor behaviors – looking times and reaction times, vocalizations and gestures, avoidance responses and proximity seeking – provide the basis for inferences about infants’ percepts, thoughts and feelings. Now, at long last, motor development, the neglected and wretched Cinderella of developmental psychology, has been rescued from the dustbin and invited to the language ball. As researchers in both motor (Adolph and Karasik) and language (Tamis-LeMonda) development, how do we feel about this? On the one hand, we embrace Iverson’s proposal that developmental changes in infants’ motor skills can affect developmental changes in linguistic, cognitive and social aspects of language acquisition. As one of many examples cited by Iverson, the transition from crawling to walking is associated with qualitative changes in the ways that infants share objects with their mothers, which in turn creates new opportunities for social interactions (Karasik, Tamis-LeMonda & Adolph, under review). We also find that infant motor development and expertise shape both the language and gestures mothers use to encourage and discourage infant actions in situations of potential risk (Karasik, Tamis-LeMonda, Adolph & Dimitropoulou, 2008), and infant exploratory and play actions are key behaviors to which mothers verbally respond during everyday interactions (Bornstein, Tamis-LeMonda, Hahn & Haynes, 2008; Tamis-LeMonda & Bornstein, 2002). Clearly, infants’ motor actions and development are a driving force in their social development and interactions. On the other hand, we feel that Iverson’s proposal only captures a small piece of the story – one in which motor development is viewed as a ‘key participant’, as Iverson puts it, in the service of the true princesses of psychology – language, cognition, perception and social interaction. An alternative approach is to recast motor development in the leading role, with perception, cognition and social development playing supporting roles. Perception is a necessary condition for adaptive motor control; motor actions must be selected, modified, discovered and constructed to suit the constraints and demands of the current situation (Adolph & Berger, 2006; Gibson & Pick, 2000). And, more germane to Iverson’s arguments, language and social interaction can also be key participants. Our own research illustrates the participatory role of social cognition in infant motor action. Inspired by Sorce, Emde, Campos & Klinnert’s (1985) classic study of social referencing on the visual cliff, we asked whether infants use social information from their mothers when deciding whether to descend safe and risky slopes (0°–50°). On some trials, mothers encouraged their infants to crawl or walk down the slopes, and on other trials, mothers discouraged descent (Karasik et al., 2008). If infants ignored the social information offered by their mothers, motor decisions would depend only on risk level. They did not. But neither did social information always win the day. Use of social information depended on the infants’ age (a stand-in for language knowledge and social cognition) and motor expertise. Experienced crawlers aged 1;0 refused to descend risky slopes regardless of mothers’ messages, but became slightly more cautious on safe slopes when their mothers discouraged them. Novice walkers aged 1;0 marched blithely over the edge of both safe and risky slopes, but became slightly more cautious at the steepest 50° increment when their mothers discouraged them (Adolph, Tamis-LeMonda, Ishak, Karasik & Lobo, 2008). By age 1;6, when infants are sophisticated consumers of social information and have accumulated six months of walking experience, they only deferred to mothers’ advice when risk level was uncertain: on slopes at the limits of their abilities, infants walked when mothers said go and avoided when mothers said no. Otherwise, infants ignored their mothers’ advice by avoiding steep slopes and crossing safe ones regardless of the social message (Tamis-LeMonda, Adolph, Lobo, Karasik & Dimitropoulou, 2008). However, when infants aged 1;6 were outfitted with slippery Teflon-soled shoes that diminished their walking skill, they now relied on mothers’ social messages to decide whether formerly safe slopes were safe or risky (Adolph, Tamis-LeMonda, Karasik & Lobo, in prep.). Clearly, when social information is available – as it is in the everyday lives of infants and caregivers – infants weigh and integrate social messages with the perceptual information generated by their own exploratory activities in making decisions about action. Cross-cultural research makes an even stronger case for social influences on motor development. Childrearing practices – how infants are held, carried, bathed, dressed, exercised, toileted, and so on – can affect the onset of motor skills, their developmental trajectories and their ultimate form (Adolph, Karasik & Tamis-LeMonda, 2009). For example, rigorous Jamaican bathing routines accelerate the onset of sitting and walking (Hopkins & Westra, 1988; 1989), and restricted time in a prone position delays the onset of crawling (Davis, Moon, Sachs & Ottolini, 1998). Daily exercise of infants’ upright stepping changes the developmental trajectory in alternating leg movements from the characteristic U-shape (in which stepping is seen in early infancy, disappears, and then ‘reappears’ when infants begin walking) to a monotonic increase (Zelazo, 1983). Trajectories can even stop short: parents’ lack of encouragement to walk resulted in a family of adult hand-and-foot crawlers (Humphrey, Skoyles & Keynes, 2005). Foot-binding of young Chinese girls (Fang & Yu, 1960; Ping, 2000), load carriage in East African girls (Heglung, Willems, Penta & Cavagna, 1995; Maloiy, Heglung, Prager, Cavagna & Taylor, 1986) and endurance running in the Tarahumaran Indians (McDougall, 2009) alters the form of walking movements. The Chinese girls relearned how to walk with tottering steps on three-inch feet. The African load carriers alter the form of their walking movements to maximize the energetics of gait dynamics. And the Tarahumarans regularly run ultra-marathon distances by changing the positions of their heads, torsos and feet. Even the very skills we acquire – chopsticks versus spoons, body surfing versus bicycling – are affected by social context. Finally, beyond both its supporting and leading roles vis-a-vis perception, cognition and social development, motor development is a model system for understanding fundamental developmental issues such as flexibility, prospectivity, agency, emergence of new forms, continuity and discontinuity, variability and variety of means, individual differences, age and experience, sampling intervals, and so on (Adolph & Berger, 2006; Adolph & Joh, 2007; Gibson, 1997). For example, the specificity of learning between experienced crawlers who precisely perceive affordances for locomotion and novice walkers who haplessly do not, suggests that flexibility of behavior in the face of novel challenges (slopes, cliffs, etc.) requires something more than the acquisition of static rules (e.g. ‘steep slopes and big cliffs are dangerous’). Yesterday’s cliff can become today’s step as crawling skill improves; and yesterday’s step can become today’s cliff when infants transition from crawling to walking. Flexible and adaptive responding requires infants to gauge each potential obstacle relative to the current status of their bodies and skills. Of course, coping with novel and variable circumstances is not limited to the motor domain. The ‘learning to learn’ evidenced by infants as they approach the brink of a slope or a cliff may prove to be a useful notion for understanding flexibility and generativity in language, cognition and social interaction. We suggest that a broader appreciation for general principles of developmental psychology may show poor Cinderella to be a true princess who needn’t wait for rescue by a handsome prince or a make-over by a fairy godmother to be worthy of attending the ball.

The content of mothers' emotional, verbal, and gestural communication to their infants was examined under conditions of potential physical risk in a laboratory motor task. Mothers encouraged and discouraged their 12- and 18-month-old infants to crawl or walk down a sloping walkway. Mothers expressed positive affect on nearly every trial. They rarely expressed purely negative affect in their faces and voices, even when discouraging. Instead, they discouraged infants with a mixture of positive and negative expressions. In both encourage and discourage conditions, mothers coupled their emotional messages with rich verbal and gestural information to elicit infants' attention, regulate their location, guide their actions, and describe the situation and potential consequences of their actions. The content of mothers' communication was attuned to infants' age and locomotor experience.

Motor development – traditionally studied in WEIRD populations – falls victim to assumptions of universality similar to other domains described by Henrich et al. However, cross-cultural research illustrates the extraordinary diversity that is normal in motor skill acquisition. Indeed, motor development provides an important domain for evaluating cultural challenges to a general behavioral science.

The social cognition and perception-action literatures are largely separate, both conceptually and empirically. However, both areas of research emphasize infants' emerging abilities to use available information--social and perceptual information, respectively--for making decisions about action. Borrowing methods from both research traditions, this study examined whether 18-month-old infants incorporate both social and perceptual information in their motor decisions. The infants' task was to determine whether to walk down slopes of varying risk levels as their mothers encouraged or discouraged walking. First, a psychophysical procedure was used to determine slopes that were safe, borderline, and risky for individual infants. Next, during a series of test trials, infants received mothers' advice about whether to walk. Infants used social information selectively: They ignored encouraging advice to walk down risky slopes and discouraging advice to avoid safe slopes, but they deferred to mothers' advice at borderline slopes. Findings indicate that 18-month-old infants correctly weigh competing sources of information when making decisions about motor action and that they rely on social information only when perceptual information is inadequate or uncertain.