Organizing the Methodological Toolbox: Lessons Learned From Implementing Developmental Methods Online

Adapting studies typically run in the lab, preschool, or museum to online data collection presents a variety of challenges. The solutions to those challenges depend heavily on the specific questions pursued, the methods used, and the constraints imposed by available technology. We present a partial sample of solutions, discussing approaches we have developed for adapting studies targeting a range of different developmental populations, from infants to school-aged children, and utilizing various online methods such as high-framerate video presentation, having participants interact with a display on their own computer, having the experimenter interact with both the participant and an actor, recording free-play with physical objects, recording infant looking times both offline and live, and more. We also raise issues and solutions regarding recruitment and representativeness in online samples. By identifying the concrete needs of a given approach, tools that meet each of those individual needs, and interfaces between those tools, we have been able to implement many (but not all) of our studies using online data collection during the COVID-19 pandemic. This systematic review aligning available tools and approaches with different methods can inform the design of future studies, in and outside of the lab.

Social Inference May Guide Early Lexical Learning

We incorporate social reasoning about groups of informants into a model of word learning, and show that the model accounts for infant looking behavior in tasks of both word learning and recognition. Simulation 1 models an experiment where 16-month-old infants saw familiar objects labeled either correctly or incorrectly, by either adults or audio talkers. Simulation 2 reinterprets puzzling data from the Switch task, an audiovisual habituation procedure wherein infants are tested on familiarized associations between novel objects and labels. Eight-month-olds outperform 14-month-olds on the Switch task when required to distinguish labels that are minimal pairs (e.g., “buk” and “puk”), but 14-month-olds' performance is improved by habituation stimuli featuring multiple talkers. Our modeling results support the hypothesis that beliefs about knowledgeability and group membership guide infant looking behavior in both tasks. These results show that social and linguistic development interact in non-trivial ways, and that social categorization findings in developmental psychology could have substantial implications for understanding linguistic development in realistic settings where talkers vary according to observable features correlated with social groupings, including linguistic, ethnic, and gendered groups.

Does the understanding of complex dynamic events at 10 months predict vocabulary development?

abstract By the end of their first year, infants can interpret many different types of complex dynamic visual events, such as caused-motion, chasing, and goal-directed action. Infants of this age are also in the early stages of vocabulary development, producing their first words at around 12 months. The present work examined whether there are meaningful individual differences in infants’ ability to represent dynamic causal events in visual scenes, and whether these differences influence vocabulary development. As part of the longitudinal Language 0–5 Project, 78 10-month-old infants were tested on their ability to interpret three dynamic motion events, involving (a) caused-motion, (b) chasing behaviour, and (c) goal-directed movement. Planned analyses found that infants showed evidence of understanding the first two event types, but not the third. Looking behaviour in each task was not meaningfully related to vocabulary development, nor were there any correlations between the tasks. The results of additional exploratory analyses and simulations suggested that the infants’ understanding of each event may not be predictive of their vocabulary development, and that looking times in these tasks may not be reliably capturing any meaningful individual differences in their knowledge. This raises questions about how to convert experimental group designs to individual differences measures, and how to interpret infant looking time behaviour.

Infants look longer at colours that adults like when colours are highly saturated

The extent to which aesthetic preferences are ‘innate’ has been highly debated (Reber, Schwarz, & Winkielman, Personality and Social Psychology Review, 8(4), 364–382, 2004). For some types of visual stimuli infants look longer at those that adults prefer. It is unclear whether this is also the case for colour. A lack of relationship in prior studies between how long infants look at different colours and how much adults like those colours might be accounted for by stimulus limitations. For example, stimuli may have been too desaturated for infant vision. In the current study, using saturated colours more suitable for infants, we aim to quantify the relationship between infant looking and adult preference for colour. We take infant looking times at multiple hues from a study of infant colour categorization (Skelton, Catchpole, Abbott, Bosten, & Franklin, Proceedings of the National Academy of Sciences of the United States of America, 114(21), 5545–5550, 2017) and then measure adult preferences and compare these to infant looking. When colours are highly saturated, infants look longer at colours that adults prefer. Both infant looking time and adult preference are greatest for blue hues and are least for green-yellow. Infant looking and adult preference can be partly summarized by activation of the blue-yellow dimension in the early encoding of human colour vision. These findings suggest that colour preference is at least partially rooted in the sensory mechanisms of colour vision, and more broadly that aesthetic judgements may in part be due to underlying sensory biases.

Does the understanding of complex dynamic events at 10 months predict vocabulary development?

By the end of their first year, infants are able to interpret many different types of complex dynamic visual events, such as caused-motion, chasing, and goal-directed action. Infants of this age are also in the early stages of vocabulary development, producing their first words at around 12 months. The present work examined whether there are meaningful individual differences in infants’ ability to represent dynamic causal events in visual scenes and whether these differences influence vocabulary development. As part of the longitudinal Language 0-5 Project, 78 10-month-old infants were tested on their ability to interpret three dynamic motion events, involving (a) caused-motion, (b) chasing behaviour, and (c) goal-directed movement. Planned analyses found that infants showed evidence of understanding the first two event types, but not the third. Looking behaviour in each task was not meaningfully related to vocabulary development, nor were there any correlations between the tasks. The results of additional exploratory analyses and simulations suggested that the infants’ understanding of each event may not be predictive of their vocabulary development, and that looking times in these tasks may not be reliably capturing any meaningful individual differences in their knowledge. This raises questions about how to convert experimental group designs to individual differences measures, and how to interpret infant looking time behaviour.

Infants’ use of interpersonal asynchrony as a signal for third-party affiliation

Infants use social cues to form expectations about the social relationships of others. For example, they expect agents to approach helpful partners and avoid hindering partners. They expect individuals with shared food preferences to be affiliates and individuals with opposing food preferences to be nonaffiliates. Interpersonal synchrony and asynchrony are important signals that adults use to guide third-party understanding. Specifically, we expect synchronous partners to be higher in rapport than asynchronous partners. Here, using a within-subjects design, we investigated if 12- to 14-month-old infants ( n = 62) also use interpersonal synchrony and/or asynchrony to make sense of third-party social relationships. A violation of expectations paradigm adapted from Liberman and colleagues was used. Infant looking time was recorded while watching videos of two women. The women moved either synchronously or asynchronously during familiarization trials, and subsequently interacted either in a friendly way (waving) or an unfriendly way (turning away) on test trials. Results revealed that infants expected asynchronous partners to be nonaffiliates but showed no significant expectation for synchronous partners. These results suggest that infants use interpersonal movement to understand their social world from as early as 12 months of age.

Fearful but not happy expressions boost face detection in human infants

Human adults show an attentional bias towards fearful faces, an adaptive behaviour that relies on amygdala function. This attentional bias emerges in infancy between 5 and 7 months, but the underlying developmental mechanism is unknown. To examine possible precursors, we investigated whether 3.5-, 6- and 12-month-old infants show facilitated detection of fearful faces in noise, compared to happy faces. Happy or fearful faces, mixed with noise, were presented to infants ( N = 192), paired with pure noise. We applied multivariate pattern analyses to several measures of infant looking behaviour to derive a criterion-free, continuous measure of face detection evidence in each trial. Analyses of the resulting psychometric curves supported the hypothesis of a detection advantage for fearful faces compared to happy faces, from 3.5 months of age and across all age groups. Overall, our data show a readiness to detect fearful faces (compared to happy faces) in younger infants that developmentally precedes the previously documented attentional bias to fearful faces in older infants and adults.