and “pretend”). These are the early markers of their growing awareness of their own minds and the fact that their own understandings may be tentative, incomplete, or incorrect in relation to those of other people. Beyond recognizing ideas as such, by about the age of 4 (if not sooner) children also understand that individuals can believe things that may be false. False belief is an essential component to mature learning as well as scientific practice. The inquiry process hinges on treating ideas as plausible and testing them empirically before determining their value.
By school age, most children will easily distinguish objects from simple symbols representing those objects (e.g., an actual milk bottle from a drawing of one) (see, e.g., DeLoache, 2004). Their ability to understand symbol systems and representational models underpins a capacity to understand and formulate explanatory models in science. This capacity emerges quite early and is in place before children enter school. For example, in studies conducted by DeLoache and her colleagues, children see an object hidden in a small-scale model of a room, and they are asked to find the object in the actual room. To be successful at this task, children must achieve the insight that the scale model is both an object in its own right and that it represents something about the larger room. This task is quite difficult for 2½-year-olds, although on versions of the task using scale models, by 3 years of age, children typically succeed.
Young children are also surprisingly sophisticated in the sources of information they consider. Contrary to pervasive views of children as “lone scientists” or “concrete operators” who rely only on firsthand observations and experiments, children actually draw on information from a range of sources. These include their own perception, as well as the testimony of other children and adults, and the inferences they draw from observations and testimony (Harris, 2002). Furthermore, they also track the sources of information that influence their thinking. In the preschool years, children begin to identify clear sources of their beliefs. They accurately attribute their ideas to perception, the testimony of others, or inference from observations (Montgomery, 1992; Perner, 1991; Sodian and Wimmer, 1987; Taylor, 1988; Wellman, 1990).
Scientific practice and mature learning involve making informed judgments of the quality and truthfulness of evidence and arguments, as well as identification of reliable sources of expert knowledge. By the time children reach kindergarten, the rudiments of these intellectual skills are in hand. Children as young as age 2 make basic distinctions in the sources from which they gather information. For example, children viewing the same scene on TV and through a window will treat their observations differently