Holding multiple category representations: The role of age, theory of mind, and rule switching in children's developing cross-classification abilities

Cross-classification, the ability to categorize multifaceted entities in many ways, is a remarkable cognitive milestone for children. Past work has focused primarily on documenting the timeline for when children reach cross-classification competence. However, it is not well understood what cognitive factors underpin children's improvements. The current study aimed to examine the contributions of age, theory of mind, and rule switching to children's cross-classification development. We tested 3- to 5-year-old children (N = 75) using a cross-classification task, the Theory of Mind Task Battery, and the Three-Dimensional Change Card Sort test. The results revealed that age and theory of mind predict children's cross-classification over and above the effects of rule switching. The results also revealed that advanced-level theory of mind reasoning is a particularly strong predictor of cross-classification development. These findings increase understanding of cross-classification within children's broader cognitive development.

Gratitude for Categories of Needs Before and During the COVID-19 Pandemic

This naturalistic observation study investigated the influence of broad societal events such as the COVID-19 pandemic on public expressions of gratitude. Spontaneously produced gratitude expressions posted by individuals (N = 159) in an online discussion forum were extracted at three time periods (during the pandemic, one year pre-pandemic, and 2 years pre-pandemic). The gratitude expressions were coded for the categories of deficiency and growth needs based on Maslow's Theory of Motivation. The results demonstrate a higher frequency of gratitude expressions for growth opportunities during the COVID-19 pandemic compared to 2 years prior. The results also demonstrate a higher frequency of gratitude for the fulfillment of deficiency needs compared to growth needs within each of the years, highlighting the overall salience of this category. These findings reveal the capacity of broad societal events to impact public gratitude expressions for needs fulfilment, which has implications for policies and programs intended to meet needs during a global crisis.

Parental reports of children’s biological knowledge and misconceptions

Children’s misconceptions about five specific biological concepts—life, aging, reproduction, illness, and death—were investigated using a parent survey. Parents of 3- to 4-year-olds ( N 1/4 125) and parents of 5- to 6-year-olds ( N 1/4 145) completed a questionnaire about their child’s knowledge and misconceptions involving these concepts. Parents reported that misconceptions were common among 3- to 6-year-olds, particularly for reproduction and death. Parents reported a greater reluctance to talk with their children about death and reproduction and also thought their children should learn about these concepts at a later age than other biological concepts. One third of the misconceptions reported by parents occurred at the boundary between different domains, where information from another domain (i.e., physics or psychology) was incorrectly associated with the biological domain. Parents of 5- to 6-year-olds reported fewer misconceptions than parents of 3- to 4-year-olds, suggesting that these misconceptions are open to change and are eventually replaced by accurate biological knowledge.

Trust and doubt: An examination of children's decision to believe what they are told about food

The domain of food is one that is highly relevant and vital to the everyday lives of children. However, children's reasoning about this domain is poorly understood within the field of developmental psychology. Because children's learning about food, including its evaluative components (e.g., health, taste) is so heavily dependent on information conveyed by other people, a major developmental challenge that children face is determining who to distrust regarding food. In three studies, this investigation examined how 3- and 4-year-olds and adults (N=312) use different cues to determine when to ignore informant information (i.e., distrust what an informant tells them by choosing an alternative) in food- and non-food-specific scenarios. The results of Study 1 indicated that by age 4 years, children are less trusting of inaccurate sources of information compared with sources that have not demonstrated previous inaccuracy. Study 2 revealed that these results are applicable across the domain of objects. The results of Study 3 indicated that by age 4, children trust benevolent sources more often than malevolent ones. Thus, when reasoning about the evaluative components of food, by age 4, children appraise other people's untrustworthiness by paying attention to their inaccuracy and malevolence.

Predictors of children's food selection: The role of children's perceptions of the health and taste of foods

Food selection, decisions about which foods to eat, is a ubiquitous part of our everyday lives. The aim of this research was to investigate the role of taste versus health perceptions in 4- and 6-year-old children's food selection. In this study, children and young adults were asked to rate the health and presumed taste of foods. Participants were also asked to indicate whether they would eat these foods in a food selection task. Overall, the results showed that taste was a strong predictor of individuals' food selection above and beyond the variance associated with age, health ratings, and interactions between age and presumed taste ratings as well as age and health ratings. These results contribute to our understanding of children's food selection, and the relative importance of a food's taste versus health in the development of these decisions.

Inductive selectivity in children's cross-classified concepts

Cross-classified items pose an interesting challenge to children's induction as these items belong to many different categories, each of which may serve as a basis for a different type of inference. Inductive selectivity is the ability to appropriately make different types of inferences about a single cross-classifiable item based on its different category memberships. This research includes 5 experiments that examine the development of inductive selectivity in 3-, 4-, and 5-year-olds (n=272). Overall, the results show that by age 4, children have inductive selectivity with taxonomic and script categories. That is, children use taxonomic categories to make biochemical inferences about an item whereas script categories to make situational inferences about an item.

The role of external sources of information in children's evaluative food categories

Evaluative food categories are value-laden assessments which reflect the healthfulness and palatability of foods (e.g., healthy/unhealthy, yummy/yucky). In a series of three studies, this research examines how 3- to 4-year-old children (N = 147) form evaluative food categories based on input from external sources of information. The results indicate that children prefer to ask a mom and teacher over a cartoon and child for information about the evaluative status of foods. However, children are cautious to accept information about healthy foods from all of the external sources compared to unhealthy, yummy, and yucky foods. The results also indicate that providing information about the positive taste of healthy foods helps to encourage children to select healthy foods to eat. Taken together, these results have potential implications for children's health and nutrition education.

A theory-based approach to teaching young children about health: A recipe for understanding

The theory-theory account of conceptual development posits that children's concepts are integrated into theories. Concept learning studies have documented the central role that theories play in children's learning of experimenter-defined categories, but have yet to extensively examine complex, real-world concepts such as health. The present study examined whether providing young children with coherent and causally-related information in a theory-based lesson would facilitate their learning about the concept of health. This study used a pre-test/lesson/post-test design, plus a five month follow-up. Children were randomly assigned to one of three conditions: theory (i.e., 20 children received a theory-based lesson); nontheory (i.e., 20 children received a nontheory-based lesson); and control (i.e., 20 children received no lesson). Overall, the results showed that children in the theory condition had a more accurate conception of health than children in the nontheory and control conditions, suggesting the importance of theories in children's learning of complex, real-world concepts.

Not as easy as pie. Disentangling the theoretical and applied components of children's health knowledge

While there has been substantial research on children's dietary habits and physical activity level, there has been little work linking children's understanding of these concepts and how they apply them. This study aims to elucidate the association between two concepts that have not been distinguished in previous work; theoretical and applied health knowledge. Four-year-old children completed measures of theoretical and applied health knowledge regarding vegetables, fatty foods, physical, and sedentary activities. Results indicate that children's theoretical and applied health knowledge are distinct concepts that are positively associated. That is, children who accurately identify the relative health of foods and activities are more likely to be able to select foods and activities that promote their body's health.

Acquiring Non-Object Terms: The Case for Time Words

We address the issue of children's understanding of abstract words with two studies on preschoolers' knowledge of the time-duration words minutes, hours, days, and years. The first study examines 4- and 5-year-olds' ability to answer questions about durations of common phenomena with duration terms. The second study examines 4- to 6-year-olds' comprehension of duration terms with a forced-choice pointing task. Both show that preschoolers' knowledge of such words is incomplete, but that it adheres to the pattern proposed in previous work with toddlers for abstract words. More specifically, children form lexical domains for such words even before they know their individual meanings, thereby allowing the children to often respond appropriately but not usually correctly to questions about abstract dimensions like time.

Children's Evaluative Categories and Inductive Inferences within the Domain of Food

Evaluative categories include items that share the same value- laden assessment. Given that these categories have not been examined extensively within the child concepts literature, the present research explored evaluative categorization and induction within the domain of food as a test case. Specifically, two studies examined the categories of healthy and junky foods in children aged 4 and 7 years. Study 1 showed that by aged 4 years, children appropriately apply the evaluative categories of healthy and junky foods to a variety of different foods. Study 2 showed that by age 4 years, children also selectively use the evaluative categories of healthy and junky foods for inductive inferences about the human body, but not for arbitrary or unrelated inferences. Taken together, these results highlight the importance of evaluative processing in young children's categorization and induction.

Cross-classification and category representation in children's concepts

Items commonly belong to many categories. Cross-classification is the classification of a single item into more than one category. This research explored 2- to 6-year-old children's use of 2 different category systems for cross-classification: script (e.g., school-time items, birthday party items) and taxonomic (e.g., animals, clothes). The results of Experiments 1 and 2 show that by a young age, children are able to cross-classify items into both category systems. Experiment 3 found that children mentally represent cross-classified items as simultaneously belonging to both taxonomic and script categories. Experiment 4 found that children often, but do not always, spontaneously activate taxonomic and script cross-classifications. Overall, the results demonstrate that from an early age children form and use both taxonomic and script categories for cross-classification.

An apple a day keeps the doctor away: Children's evaluative categories of food

This study explores how children evaluatively categorize foods based on their nutritional value. Three-year-olds, four-year-olds, seven-year-olds, and adults completed a task in which they categorized a list of 70 foods as healthy or junky. The results showed important developmental differences in participants' ability to accurately classify foods as healthy/junky and to provide relevant justifications for these classifications. These results suggest that a large amount of category learning occurs with development, especially as children incorporate different types of information about food nutrition into their evaluative category representations.

An apple is more than just a fruit: cross-classification in children's concepts

This research explored children's use of multiple forms of conceptual organization. Experiments 1 and 2 examined script (e.g., breakfast foods), taxonomic (e.g., fruits), and evaluative (e.g., junk foods) categories. The results showed that 4- and 7-year-olds categorized foods into all 3 categories, and 3-year-olds used both taxonomic and script categories. Experiment 3 found that 4- and 7-year-olds can cross-classify items, that is, classify a single food into both taxonomic and script categories. Experiments 4 and 5 showed that 7-year-olds and to some degree 4-year-olds can selectively use categories to make inductive inferences about foods. The results reveal that children do not rely solely on one form of categorization but are flexible in the types of categories they form and use.

Promoter element for transcription of unrearranged T-cell receptor beta-chain gene in pro-T cells

The hallmark of T- and B-lymphocyte development is the rearrangement of variable (V), diversity (D), and joining (J) segments of T-cell receptor (TCR) and immunoglobulin (Ig) genes to generate a diverse repertoire of antigen receptor specificities in the immune system. The process of V(D)J recombination is shared in the rearrangement of all seven antigen receptor genes and is controlled by changes in chromatin structure, which regulate accessibility to the recombinase apparatus in a lineage- and stage-specific manner. These chromatin changes are linked to transcription of the locus in its unrearranged (germline) configuration. To understand how germline transcription of the TCRbeta-chain gene is regulated, we determined the structure of germline transcripts initiating near the Dbeta1 segment and identified a promoter within this region. The Dbeta1 promoter is active in the presence of the TCRbeta enhancer (Ebeta), and in this context, exhibits preferential activity in pro-T versus mature T-cell lines, as well as T- versus B-lineage specificity. These studies provide insight into the developmental regulation of TCRbeta germline transcription, one of the earliest steps in T-cell differentiation.