Research Interests

 

Much of what we know could only have been learned from other people (e.g., Harris, 2002; Tomasello, 1999). For example, I know that the earth is round, but all of my own observations suggest that it is flat. I know that there are such things as subatomic particles, but I've never seen one. For children to be able to take advantage of their culture's accumulated knowledge and expertise, they have to be willing to accept some information “on faith,” even if it seems counterintuitive or cannot easily be verified through first-hand experience. At the same time, however, children cannot simply believe everything they are told because people sometimes say things that are wrong. The goal of my research program is to understand how very young children balance the benefits of credulity against the need for skepticism.

 

A Surprising Degree of Credulity

 

One line of my research addresses how children resolve conflicts between what another person tells them (“testimony”) and their own, independently acquired beliefs. As philosophers have long noted, information acquired from another person seems qualitatively different from—somehow less “good” than—information acquired on the basis of one's own experience (e.g., Hume, 1748; Locke, 1689; Plato, 360 BCE). And yet, my research has shown that testimony is such a powerful source of information that it can lead children to “disbelieve their eyes.”

 

Credulity about category membership. In one series of studies, I found that children would often favor an adult's testimony about the category to which an object belonged over their own, perceptually based expectations about that object (Jaswal, 2004, 2007; Jaswal & Malone, 2007; Jaswal & Markman, 2002, 2007). For example, 2- and 3-year-olds who heard a key-like object referred to as a “spoon” usually inferred that it was used to eat cereal rather than to start a car; in contrast, those who heard it referred to neutrally usually made the opposite inference. Importantly, children who heard the key-like object referred to as a “spoon” really seemed to believe this surprising news: When another, apparently naïve individual later asked what the object was, they usually said it was a “spoon” even though it looked like a key (Jaswal, Lima, & Small, 2009).

 

Credulity about events in the physical world. Young children have a number of naïve beliefs about the physical world: They expect that objects will continue to exist when hidden from view, that they cannot move from one location to another without traversing the intervening space, and so on (Spelke, 1994). Some early expectations may be wrong or immature, but personal experience rather than testimony has traditionally been emphasized as the epistemological engine that corrects these errors (e.g., Piaget, 1970). In work supported by a grant from NICHD, I have investigated the extent to which testimony can influence children's beliefs about the physical world (Jaswal, 2010). In one study, for example, I found that when 2.5-year-olds heard an adult offer testimony that contradicted a naïve expectation that objects fall straight down (i.e., the “gravity bias;” Hood, 1995), they almost always trusted the adult rather than their own extremely robust (and erroneous) intuitions. In several follow-up experiments, I found that children often trusted what an adult told them even when it conflicted with an event they had actually just seen themselves. Control studies demonstrated that this deference was not the result of mere compliance. Instead, children truly seemed to believe the adult's account of the event rather than their own eyes.

 

The Origins of Skepticism

 

As just described, one line of my research has focused on the surprising degree of credulity young children sometimes evince. But as any parent can attest, children do not believe everything they are told. In a second line of research, I have investigated how children's response to testimony actually involves a complex interaction between three variables (see also Jaccard, 1981). The first is the plausibility of the testimony. Children are more likely to trust testimony that is only moderately discrepant from their expectations than testimony that is extremely discrepant. For example, 3-year-olds are more likely to accept that a key-like object is a “spoon” than they are to accept that a horse is a “spoon” (Jaswal et al., 2009).

 

A second variable is how much confidence they have in their own, pre-existing beliefs about the subject of the testimony. For example, preschoolers will readily believe that an object they have never seen before is called a “blicket” (e.g., Jaswal & Markman, 2001, 2003), but if a speaker points toward a shoe when requesting a “blicket,” they will often object (e.g., Jaswal, under review; Jaswal & Hansen, 2006). Children will also object if a speaker claims that the plural of a novel word like “wug” is irregular (e.g., “wog” rather than “wugs”), because irregular forms are so rare (Jaswal, McKercher, & VanderBorght, 2008; Jaswal, McKercher, & Kondrad, in preparation). Likewise, although 2.5-year-olds will often believe an adult's account of an event even if it conflicts with what they have just seen, they are significantly more skeptical of the adult's testimony if they have earlier had a brief training experience that allowed them to build up confidence in their independently acquired beliefs (Jaswal, 2010).

 

A third variable is how much confidence they have in the speaker. Young children can coordinate a variety of cues to the likely credibility of a speaker. For example, they prefer to learn new words from adults rather than from peers; but if a particular adult has been wrong in the past, they will actually prefer learning from a peer rather than from that unreliable adult (Jaswal & Neely, 2006; see also VanderBorght & Jaswal, 2009). Indeed, children are very sensitive to on-line cues to a speaker's credibility. For example, if a speaker hedges by saying “I think” before claiming that a key-like object is a “spoon,” otherwise credulous 3-year-olds will respond skeptically (Jaswal & Malone, 2007). Conversely, if a speaker suggests that she or he has some privileged knowledge by saying of the key-like object, “You're not going to believe this, but this is actually a ‘spoon,'” otherwise skeptical 4-year-olds will respond credulously (Jaswal, 2004; see also Jaswal, 2006).

 

Summary and Future Directions

My research program shows that, from a very early age, testimony is at least as powerful (and sometimes more powerful) a source of information as personal experience. Recent work in the lab suggests that children have a specific, highly robust bias to what they are told rather than a diffuse expectation about the beneficence of other people (Jaswal et al., 2010). Importantly, however, my work also shows that young children are not entirely credulous: A variety of factors influence how persuasive they find a piece of testimony to be.

 

On-going work with Koraly Perez-Edgar at Penn State University (supported by a grant from the Jacobs Foundation) is investigating sources of individual differences in children's skepticism and credulity. Another line of research addresses the extent to which children recognize errors in a variety of domains, and how the errors people make influence children's judgments of those individuals (Kondrad & Jaswal, in prep). We are also interested in characterizing the effect of social signals other than testimony on children's judgments of other individuals (e.g., Palmquist et al., 2012; Palmquist & Jaswal, 2012).

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