The Collaborative Nature of Testimonial Learning.

Children's testimonial learning often occurs in epistemic collaborations with others. In this paper, we will discuss ways in which cultural learning emerges in social and interpersonal contexts, and is intrinsically supported and guided by children's collaborative capacities. Much work in cultural learning has focused on children's examination of speaker and model characteristics, but more recent research has investigated the interactive aspects of testimonial exchanges. We will review evidence that children (1) participate in the interpersonal commitments that are shared in testimonial transactions by way of direct address and epistemic buck passing, (2) participate in social groups that affect their selective learning in nuanced ways, and (3) may detect epistemic harms by listeners who refuse to believe sincere and accurate speakers. Implications for conceptualizing children's testimonial learning as an interactive mechanism of collaboration will be discussed.

Understanding the value of telescopic testimony: With age, a predominantly White Midwestern sample of children credits knowledge to speakers whose statements go beyond the evidence.

One primary value of testimony lies in its ability to extend our powers of observation. Do children credit more knowledge to speakers whose testimony goes beyond firsthand observation? The current study investigated 3- to 8-year-old children's (N = 180) and adults' (N = 20) knowledge attributions to speakers who made claims regarding perceptually evident features of a novel animal (e.g., "is brown") or claims regarding perceptually absent features (e.g., "eats insects"). By 7 years of age, children and adults attributed more knowledge to speakers who discussed telescopic information and generalized their knowledge to other domains. Because the knowledge base of child listeners expands with age, they place increased value on telescopic information and the speakers who provide it.

"I know it's complicated": Children detect relevant information about object complexity.

Mechanistic complexity is an important property that affects how we interact with and learn from artifacts. Although highly complex artifacts have only recently become part of human material culture, they are ever-present in contemporary life. In previous research, children successfully detected complexity contrasts when given information about the functions of simple and complex objects. However, whether children spontaneously favor relevant information about an object's causal mechanisms and functions when trying to determine an object's complexity remains an open question. In Study 1, 7- to 9-year-olds and adults, but not 5- and 6-year-olds, rated information about relevant actions (e.g., the difficulty in fixing an object) as more helpful than information about irrelevant actions (e.g., the difficulty in spelling an object's name) for making determinations of mechanistic complexity. Only in Study 2, in which the relevance contrasts were extreme, did the youngest age group rate relevant actions as more helpful than irrelevant actions. In Study 3, in which participants rated the complexity of the actions themselves, participants performed differently than in the previous studies, suggesting that children in the prior studies did not misinterpret the study instructions as prompts to rate the actions' complexity. These results suggest that the ability to detect which object properties imply complexity emerges during the early school years. Younger children may be misled by features that are not truly diagnostic of mechanistic complexity, whereas older children more easily disregard such features in favor of relevant information.

Looking smart: Preschoolers' judgements about knowledge based on facial appearance.

Preschoolers use others' behaviours to make inferences about what traits they possess (Harris et al., 2018, Ann. Rev. Psychol., 69, 251). The current study examined whether 4- and 5-year-olds also associate others' behaviour with how they appear on the surface. Specifically, we asked whether children's sensitivity to different face-traits (e.g., Cogsdill et al., 2014, Psychol. Sci., 25, 1132) would bias them to associate knowledgeable behaviours with faces that adults rate as highly competent- or trustworthy-looking. We find that preschoolers expect puppets with trustworthy-looking faces to be knowledgeable about the functions of familiar objects. In contrast, children did not match a puppet's knowledge to facial features that adults rate as varying in competence. These data suggest that children, like adults, are biased to associate facial appearance and behaviour. Furthermore, this bias appears to be rooted in a response to the same facial features that have been found to govern judgements of trustworthiness across development (e.g., Jessen & Grossmann, 2016, J. Cogn. Neurosci., 28, 1728). Statement of contribution What is already known on this subject? Preschoolers selectively trust others using epistemic and non-epistemic cues (Harris et al., 2018). Preschoolers associate specific faces with trustworthiness and competence (Cogsdill et al., 2014). What the present study adds? Preschoolers infer that trustworthy-looking characters will behave knowledgeably. Preschoolers do not infer that competent-looking characters will behave knowledgeably. Children's reliability judgements are influenced by others' appearance.

Cake or broccoli? Recency biases children's verbal responses.

One of the greatest challenges of developmental psychology is figuring out what children are thinking. This is particularly difficult in early childhood, for children who are prelinguistic or are just beginning to speak their first words. In this stage, children's responses are commonly measured by presenting young children with a limited choice between one of a small number of options (e.g., "Do you want X or Y?"). A tendency to choose one response in these tasks may be taken as an indication of a child's preference or understanding. Adults' responses are known to exhibit order biases when they are asked questions. The current set of experiments looks into the following question: do children demonstrate response biases? Together, we show that 1) toddlers demonstrate a robust verbal recency bias when asked "or" questions in a lab-based task and a naturalistic corpus of caretaker-child speech interactions, 2) the recency bias weakens with age, and 3) the recency bias strengthens as the syllable-length of the choices gets longer. Taken together, these results indicate that children show a different type of response bias than adults, recency instead of primacy. Further, the results may suggest that this bias stems from increased constraints on children's working memory.