Taking decisions seriously: young children's understanding of conventional truth.

Research suggests that young children may see a direct and one-way connection between facts about the world and epistemic mental states (e.g., belief). Conventions represent instances of active constructions of the mind that change facts about the world. As such, a mature understanding of convention would seem to present a strong challenge to children's simplified notions of epistemic relations. Three experiments assessed young children's abilities to track behavioral, representational, and truth aspects of conventions. In Experiment 1, 3- and 4-year-old children (N = 30) recognized that conventional stipulations would change people's behaviors. However, participants generally failed to understand how stipulations might affect representations. In Experiment 2, 3-, 5-, and 7-year-old children (N = 53) were asked to reason about the truth values of statements about pretenses and conventions. The two younger groups of children often confused the two types of states, whereas older children consistently judged that conventions, but not pretenses, changed reality. In Experiment 3, the same 3- and 5-year-olds (N = 42) participated in tasks assessing their understanding of representational diversity (e.g., false belief). In general, children's performance on false-belief and "false-convention" tasks did not differ, which suggests that conventions were understood as involving truth claims (as akin to beliefs about physical reality). Children's difficulties with the idea of conventional truth seems consistent with current accounts of developing theories of mind.

Causal status effect in children's categorization.

The current study examined the causal status effect (weighing cause features more than effect features in categorization) in children. Adults (Study 1) and 7-9-year-old children (Study 2) learned descriptions of novel animals, in which one feature caused two other features. When asked to determine which transfer item was more likely to be an example of the animal they had learned, both adults and children preferred an animal with a cause feature and an effect feature rather than an animal with two effect features. This study is the first direct demonstration of the causal status effect in children.

The inheritance of desired characteristics: Children's view of the role of intention in parent-offspring resemblance.

Two studies examined children's beliefs about maternal intention as a mechanism for trait inheritance. In Study 1, 42 preschool-aged (4 to 5 years old) children and 81 adults were shown pictures of adult women (mothers) and were asked to identify their daughters. In the critical condition participants were asked to choose between a girl who shared an attribute with the mother and a girl who had the attribute desired by the mother. Trait types included physically heritable traits, nonheritable traits, and beliefs. Results from this study suggest that preschoolers do believe that maternal intention plays a role in the inheritance of physical traits. Study 2 was designed to determine whether preschoolers recognize limits on both the efficacy and the timing of maternal intention. Results suggest that children see some properties as outside of maternal control. Further, they do seem to see maternal intentions as operating prior to birth. One finding of these studies is that preschoolers may not have strong intuitions that offspring will resemble their parents. In addition, children seem to have different intuitions about the mechanisms of inheritance than do adults.

Young children's predictions of illness: failure to recognize probabilistic causation.

In this study preschool-age children made predictions for a set of salient probabilistic causes. Of interest was whether the children viewed outcomes of familiar causes of illness as definite or as probabilistic. In Experiment 1, children judged that a common cause would affect all members of a group in the same way. In Experiment 2, children believed they could definitely predict illness outcomes in a single case. These judgments contrasted with adults' variable and uncertain predictions. Children did recognize uncertainty in outcomes dependent on voluntary choices. Experiment 3 presented both high- and low-potency causes of illness. Children treated all causes of illness as nonprobabilistic. These results are discussed in the context of children's understanding of causal relations and the sources of variability.

Natural and artifactual kinds: are children realists or relativists about categories?

Research in cognitive development has highlighted important differences between conceptions of natural kinds and artifacts. One interpretation of the distinction is that natural kinds are categories one discovers, whereas artifactual kinds are invented. Four studies assessed whether children and adults saw categorization decisions as objective matters of fact or as invented conventions. Preschool-age children treated basic-level categories of animals and human-made artifacts as objective. At the superordinate level, kinds of animals were treated as more objective than were kinds of artifacts. In general, adults' judgments were similar to children's. Both children and adults have reliable and differentiated intuitions regarding category objectivity. The results from these studies are discussed in terms of their implications for structural and theory-based accounts of category naturalness.

Child health records: are they valid and useful to children and pediatric practitioners?

Children are important consumers of health care, yet neither children nor their clinical practitioners have received much attention from the health informatics community. Child health needs differ from those of adults, and the purpose of health encounters for children focus to a greater extent on health promotion and evaluation of developmental milestones. The early childhood period is critical because it is during this time the children develop the expectations and attitudes about health care that they will carry with them throughout their lives. The primary purpose of this project is to examine the congruence in communication between children and pediatric practitioners. From this examination implications will be drawn for designing pediatric clinical records and developing strategies for determining the extent to which the record serve the child's health information needs and the clinician's health service delivery needs.

Preschoolers' understanding of mental and bodily reactions to contamination: what you don't know can hurt you, but cannot sadden you.

Evidence of the operation of a biological theory might be found in children's distinction between mental (emotional) and bodily (illness) reactions to contamination. Study 1 explored whether children see emotions as voluntary but illness as outside of intentional control. Three- and 5-year-olds judged that simple volitions were insufficient to alter either outcome. Study 2 suggested that children distinguish reactions mediated by representations from those mediated by physical interactions. Children indicated that knowledge determines mental reactions to contamination, but physical contact determines bodily reactions. Study 3 explored knowledge about particulars of emotional and illness reactions. Most preschoolers did not realize that illness takes time to develop. These data suggest that preschoolers do distinguish between physical and mental reactions to contamination but have a poor understanding of the actual bodily processes involved.

Causes and symptoms in preschoolers' conceptions of illness.

The nature of children's concept of illness is of interest both to researchers in health psychology and to those studying naive theories of biology. Recent perspectives on conceptual development suggest that children's concepts are not always simpler versions of adults' concepts. Rather, children's concepts may have a variety of different structures. Two studies investigate whether preschoolers' (and adults') concept of illness has a nominal, cluster, or natural kind representation. Evidence for conceptual structure came from ascriptions of illness and from inferences about properties of illnesses. The roles of symptoms and underlying causes were investigated with respect to these judgments. Results suggest that adults' concept of illness has a property cluster (e.g., prototype) structure. Both causes and symptoms affected adults' categorization of illnesses, with neither type of feature being definitive. Adults did not see any features as universally or uniquely characteristic of illness. Children's ascriptions of illness generally matched adults'. However, children's inferences for some properties were highly correlated with judgments of illness. Thus, children may view illness as a richer source of inferences (and hence more like a natural kind) than do adults. Among the inferences explored were judgments of contagion. Children seemed to associate contagion with a particular type of causal process (infection) rather than with illness per se. Results are discussed in terms of their implications for accounts of children's biological knowledge.

Essentialism and graded membership in animal and artifact categories.

A number of studies have argued that people view membership in animal and artifact categories as a matter of degree. These studies have generally failed to distinguish between the issues of typicality and category membership. Thus, data which have been taken to demonstrate that membership is a matter of degree may only demonstrate that typicality is graded. Partly on the basis of these findings, it has been argued that some categories are organized around an underlying essence. The essence determines membership absolutely. The present paper reports a series of studies that reexamine the question of graded membership. In the first study, subjects were asked to rate both typicality and category membership for the same stimuli as a way of distinguishing the two questions. A second method relied on the intuition that disagreements about membership in all-or-none and graded categories may have different qualities. Results from both studies suggest some support for claims that membership in animal and artifact categories is a matter of degree. A third study explored the possibility that graded responses were due to conflicting, or ambiguous, sets of criteria. A task focusing on biological features did not lead to more absolute categorization. These results contradict essentialist predictions.

The role of covariation versus mechanism information in causal attribution.

Traditional approaches to causal attribution propose that information about covariation of factors is used to identify causes of events. In contrast, we present a series of studies showing that people seek out and prefer information about causal mechanisms rather than information about covariation. Experiments 1, 2 and 3 asked subjects to indicate the kind of information they would need for causal attribution. The subjects tended to seek out information that would provide evidence for or against hypotheses about underlying mechanisms. When asked to provide causes, the subjects' descriptions were also based on causal mechanisms. In Experiment 4, subjects received pieces of conflicting evidence matching in covariation values but differing in whether the evidence included some statement of a mechanism. The influence of evidence was significantly stronger when it included mechanism information. We conclude that people do not treat the task of causal attribution as one of identifying a novel causal relationship between arbitrary factors by relying solely on covariation information. Rather, people attempt to seek out causal mechanisms in developing a causal explanation for a specific event.

On wooden pillows: multiple classification and children's category-based inductions.

Previous research has indicated that preschoolers do not distinguish between properties that are generalizable within a given category and those that are not. 2 possible general constraints on children's cognition are proposed to account for these findings. 3 studies are reported that argue against the presence of such general constraints. We examine preschoolers' understanding of the properties associated with material (e.g., wood, cotton) and object (e.g., chair, pillow) categories. In Study 1, subjects consistently made inductions based on the material compositions of items when asked to predict texture and fragility. In Study 2, the same subjects judged that items that shared material would share an unfamiliar dispositional property (e.g., gets sodden in water), but items that shared object kind would share a novel functional property (e.g., used for accelerating). Study 3 tested a younger sample of 3-year-olds and found the same sensitivity to category type, albeit with larger individual differences. By age 3, children use different modes of categorization to generalize different kinds of phenomena. These results argue against general limitations on children's abilities to use categories to make inductions. Even when children lack specific theoretical knowledge, the ability to organize phenomena into domains allows children to recognize which categories are relevant in different situations. This understanding can provide a basis for the development of more specific theories.

As time goes by: children's early understanding of growth in animals.

Beliefs about naturally occurring transformations were examined in children aged 3 to 6 years in 4 experiments. Experiment 1 tested children's understanding that animals (but not artifacts) predictably get larger over time. Experiment 1a examined whether the results obtained in the first experiment could be attributed to an added memory component on the artifact task. Experiment 2 further examined beliefs about the aging of artifacts. In Experiment 3, color and shape (metamorphosis) changes of animals were investigated. At all ages, children appeared to understand that animals get larger and not smaller with age. While older children and adults allowed for rather dramatic changes in the size and shape of animals over the life span if the alternative involved decreasing in size with age, preschool children were less willing to accept these changes. Taken together, the results of these studies suggest that even young preschool children have 2 conceptual insights about natural transformations: that they are lawful and nonrandom, and that they are domain and mechanism specific. Further, children as young as age 3 are able to go beyond the perceptual appearance of animals in making judgments about transformations caused by growth. Implications for children's understanding of personal and species identity are discussed.