Vikram K. Jaswal

Adults Don't Always Know Best Preschoolers Use Past Reliability Over Age When Learning New Words

Children learn much of what they know—from words to their birth dates to the fact that the earth is round—from what other people tell them. But some people are better informants than others. One way children can estimate the credibility of a speaker is by evaluating how reliable that person has been in the past. Even preschoolers prefer learning new words from an adult who has previously labeled objects correctly rather than one who has labeled objects incorrectly (Koenig, Clement, & Harris, 2004). Children may also make predictions about a speaker on the basis of that person’s membership in a particular group. For example, 4-year-olds expect that an unfamiliar adult, but not necessarily an unfamiliar child, knows the meaning of the word hypochondriac (Taylor, Cartwright, & Bowden, 1991). Which of these two cues to a speaker’s credibility—reliability or age—do 3and 4-year-old children find more compelling?

Young Children Have a Specific, Highly Robust Bias to Trust Testimony

Why are young children so willing to believe what they are told? In two studies, we investigated whether it is because of a general, undifferentiated trust in other people or a more specific bias to trust testimony. In Study 1, 3-year-olds either heard an experimenter claim that a sticker was in one location when it was actually in another or saw her place an arrow on the empty location. All children searched in the wrong location initially, but those who heard the deceptive testimony continued to be misled, whereas those who saw her mark the incorrect location with an arrow quickly learned to search in the opposite location. In Study 2, children who could both see and hear a deceptive speaker were more likely to be misled than those who could only hear her. Three-year-olds have a specific, highly robust bias to trust what people—particularly visible speakers—say.

Turning Believers into Skeptics: 3-Year-Olds' Sensitivity to Cues to Speaker Credibility

Under most circumstances, children (and adults) can safely assume that the testimony they hear is true. In two studies, we investigated whether 3-year-olds (N = 100) would continue to hold this assumption even if the person who provided the testimony behaved in an uncertain, ignorant, and/or distracted manner. In Study 1, children were less likely to trust that, for example, a key-like object was a spoon if the speaker indicated uncertainty about her testimony (e.g., “I think this is a spoon”) than if she simply labeled the object ostensively (e.g., “This is a spoon”). In Study 2, 3-year-olds were also more skeptical about a speakers testimony when she had earlier made an obvious naming error and seemed distracted, but not when she either made an error or seemed distracted. These results indicate that 3-year-olds can respond differently to the same testimony, depending on the speakers behavior.

Looks Aren't Everything: 24-Month-Olds' Willingness to Accept Unexpected Labels

A label can efficiently convey nonobvious information about category membership, but this information can sometimes conflict with ones own expectations. Two studies explored whether 24-month-olds (N = 56) would be willing to accept a category label indicating that an animal (Study 1) or artifact (Study 2) that looked like a member of one familiar category was actually a member of a different familiar category. Results showed that children were receptive to these unexpected labels and used them as the basis for inference. These findings indicate that linguistic information can lead even toddlers to “disbelieve their eyes.”

Believing what you're told: young children's trust in unexpected testimony about the physical world.

How do children resolve conflicts between a self-generated belief and what they are told? Four studies investigated the circumstances under which toddlers would trust testimony that conflicted with their expectations about the physical world. Thirty-month-olds believed testimony that conflicted with a naive bias (Study 1), and they also repeatedly trusted testimony that conflicted with an event they had just seen (Study 2)-even when they had an incentive to ignore the testimony (Study 3). Children responded more skeptically if they could see that the testimony was wrong as it was being delivered (Study 3), or if they had the opportunity to accumulate evidence confirming their initial belief before hearing someone contradict it (Study 4). Together, these studies demonstrate that toddlers have a robust bias to trust even surprising testimony, but this trust can be influenced by how much confidence they have in their initial belief.

Learning the Rules: Observation and Imitation of a Sorting Strategy by 36-Month-Old Children

Two experiments were used to investigate the scope of imitation by testing whether 36-month-olds can learn to produce a categorization strategy through observation. After witnessing an adult sort a set of objects by a visible property (their color; Experiment 1) or a nonvisible property (the particular sounds produced when the objects were shaken; Experiment 2), children showed significantly more sorting by those dimensions relative to children in control groups, including a control in which children saw the sorted endstate but not the intentional sorting demonstration. The results show that 36-month-olds can do more than imitate the literal behaviors they see; they also abstract and imitate rules that they see another person use.

The Relative Strengths of Indirect and Direct Word Learning

Indirect word learning lacks many of the overt social-pragmatic cues to reference available in direct word learning, yet the two result in equally robust mappings when comprehension is assessed immediately after learning. The 3 studies reported here investigated how 3-year-olds (N=96) respond to more challenging tests of the relative strengths of indirect and direct word learning. In Study 1, childrens comprehension of indirectly and directly learned proper and common names was tested after a 2-day delay. Both types of learning resulted in proper name mappings that picked out an individual and in common name mappings that could be extended to another category member. In Studies 2 and 3, childrens comprehension was tested after they had been provided with additional, and sometimes inconsistent, information about the scope of previously learned words. There was a hint of a difference between indirect and direct word learning. but results overall suggested that the two were equivalent.

Can't stop believing: inhibitory control and resistance to misleading testimony

Why are some young children consistently willing to believe what they are told even when it conflicts with first-hand experience? In this study, we investigated the possibility that this deference reflects an inability to inhibit a prepotent response. Over the course of several trials, 2.5- to 3.5-year-olds (N = 58) heard an adult contradict their report of a simple event they had both witnessed, and children were asked to resolve this discrepancy. Those who repeatedly deferred to the adults misleading testimony had more difficulty on an inhibitory control task involving spatial conflict than those who responded more skeptically. These results suggest that responding skeptically to testimony that conflicts with first-hand experience may be challenging for some young children because it requires inhibiting a normally appropriate bias to believe testimony.

Imagining a Way Out of the Gravity Bias: Preschoolers Can Visualize the Solution to a Spatial Problem

Can young children visualize the solution to a difficult spatial problem? Forty-eight 3-year-olds were tested in a spatial reasoning paradigm in which they were asked to predict the path of a ball moving through 1 of 3 intertwined tubes. One group of children was asked to visualize the ball rolling down the tube before they made their predictions, a second group was given identical instructions without being asked to use visual imagery, and a third group was given no instructions. Children in the visualization condition performed significantly better than those in the other conditions, suggesting that encouraging young children to use visual imagery may help them to reason through difficult problems.

Compliance, Conversion, and Category Induction

When children hear an object referred to with a label that is moderately discrepant from its appearance, they frequently make inferences about that object consistent with the label rather than its appearance. We asked whether 3-year-olds actually believe these unexpected labels (i.e., conversion) or whether their inferences simply reflect a desire to comply with the considerable experimental demands of the induction task (i.e., compliance). Specifically, we asked how likely children would be to pass an unexpected label on to another person who had not been present during the labeling event. Results showed that children who used an unexpected label as the basis for inference passed that label on to another person about as often as they could remember it. This suggests that childrens label-based inferences do reflect conversion rather than mere compliance.