CORRECTED PROOF Copyright © The British Psychological Society Reproduction in any form (including the internet) is prohibited without prior permission from the Society 1 The British Psychological British Journal of Developmental Psychology (2008), 00, 1–12 Society q 2008 The British Psychological Society www.bpsjournals.co.uk Early tracking of informant accuracy and inaccuracy Kathleen H. Corriveau1, Kerstin Meints2 and Paul L. Harris1* 1Harvard Graduate School of Education, Harvard University, Cambridge, Massachusetts, USA 2University of Lincoln, Lincoln, UK Three- and four-year-old children (N ¼ 131) were tested for their sensitivity to the accuracy and inaccuracy of informants. Children were presented with one of three conditions. In the Accurate–Inaccurate condition, one informant named objects accurately whereas the other named them inaccurately. In the Accurate–Neutral condition, one informant named objects accurately whereas the other merely drew attention to them. Finally in the Inaccurate–Neutral condition, one informant named objects inaccurately whereas the other merely drew attention to them. In subsequent test trials, 4-year-olds preferred to seek and accept information in a selective fashion across all three conditions, suggesting that they monitor informants for both accuracy and inaccuracy. By contrast, 3-year-olds were selective in the Accurate–Inaccurate and Inaccurate–Neutral conditions but not in the Accurate–Neutral condition, suggesting that they monitor informants only for inaccuracy and take accuracy for granted. Several recent experiments have shown that young children attend to the differential accuracy of their informants. When one informant proves to be accurate and the other inaccurate, 3- and 4-year-olds prefer to seek out and accept information from the hitherto accurate informant (Cle´ment, Koenig, & Harris, 2004; Koenig, Cle´ment, & Harris, 2004). This selective trust is quite wide-ranging in its effects. Having observed that informants differ in the accuracy with which they name objects, children display selective trust not just in learning about object names from them but also in learning about object functions (Birch, Vauthier, & Bloom, in press; Corriveau, Harris, & Nelson, 2007; Koenig & Harris, 2005). Moreover, accuracy-based selectivity can override pre-existing preferences. For example, although 3- and 4-year-olds initially displayed greater trust in an adult informant rather than a child informant, this preference was reversed if the adult but not the child subsequently proved inaccurate ( Jaswal & Neely, 2006). Similarly, although 3- to 5-year-olds showed greater trust in their familiar preschool teacher rather than * Correspondence should be addressed to Dr Paul L. Harris, Harvard Graduate School of Education, Harvard University, Cambridge, MA 02138, USA (e-mail: [email protected]). DOI:10.1348/026151008X310229 CORRECTED PROOF Copyright © The British Psychological Society Reproduction in any form (including the internet) is prohibited without prior permission from the Society 2 Kathleen H. Corriveau et al. an unfamiliar teacher as an informant, this preference was reversed among older preschoolers if the familiar preschool teacher subsequently proved inaccurate (Corriveau & Harris, in press, a). Accuracy-based selectivity is also stable over time. Three- and 4-year-olds not only show selective trust in a more accurate informant immediately after observing differences in accuracy, they continue to do so the next day and even the next week (Corriveau & Harris, in press, b). Finally, although 3-year-olds only differentiate between informants who are consistently accurate as compared to consistently inaccurate, 4-year-olds are sensitive to relative differences in accuracy. For example, if one informant is predominantly – but not always – accurate and the other informant is predominantly – but not always – inaccurate, 4-year-olds, but not 3-year-olds, display more trust in the former informant (Pasquini, Corriveau, Koenig, & Harris, 2007). Taken together, these results show that preschoolers track differences between informants in their accuracy and make wide-ranging and persistent use of those differences when seeking and accepting new information. However, despite the robust evidence for such tracking, its exact basis is unclear. In all the experiments described above, one informant was accurate all or most of the time whereas the other informant was inaccurate all or most of the time. Therefore, children might adopt at least three different strategies in tracking relative accuracy. First, they might take an informant’s accuracy for granted but track and remember an informant’s inaccuracy. Thus, in using this strategy, preschoolers would adopt a stance of default trust but withdraw that default trust when they detect error. This simple model explains all the results described above by assuming that children come to mistrust an informant who is consistently or mostly inaccurate. A second possibility is that children do the reverse. They do not take accuracy for granted. Instead, they track informants’ claims for truth and take notice whenever accurate claims are made. More specifically, they build-up trust in an informant who proves to be consistently or mostly accurate. This strategy is consistent with the possibility that children might register the fact that an informant has erred but keep no record of that error. For example, they might notice when an object has been misnamed – a sensitivity that is displayed by toddlers of 16 months (Koenig & Echols, 2003) – but fail to characterize the speaker as in any way untrustworthy. Again, this model explains all recent results but it does so by emphasizing the accumulation of trust as opposed to mistrust. A third possibility is that children monitor concurrently for both truth and falsity. Not only do they accumulate trust in informants who produce true claims, they accumulate mistrust in those who make false claims. This model explains the findings reported so far by assuming that earlier studies were optimally, albeit inadvertently, designed to provoke preschoolers into maximal differentiation between the two informants with the accurate informant eliciting trust and the inaccurate informant eliciting mistrust. Of these three strategies, the first would appear to be the simplest and most plau- sible. After all, informants generally make true or accurate claims. Obvious inaccuracy in communication is the exception rather than the rule especially in the context of adult– child communication. Accordingly, it makes sense that children would bring to any unfamiliar interlocutor an expectation that he or she will be informative and accurate. Admittedly, that default trust might first be built-up on the basis of encounters with prior, accurate informants and then extended to the claims made by a newly encountered informant – an inductive strategy first identified by Hume (1748/1957) in his discussion of our belief in miracles. Still, it seems unlikely that children treat each CORRECTED PROOF Copyright © The British Psychological Society Reproduction in any form (including the internet) is prohibited without prior permission from the Society Early tracking of informants 3 new informant as worthy of trust only after he or she has proved accurate. It seems more plausible that children bring a stock of trust to each new encounter, that they take it for granted when that trust is not violated, but nevertheless notice and record signs of untrustworthiness. In order to assess whether 3- and 4-year-olds use any of the three strategies just described, particularly the first, we designed an experiment that retained many of the features of earlier studies but the initial familiarization period with the two informants was systematically varied. In condition 1 (Accurate–Inaccurate), the earlier, standard procedure was replicated in that children were presented with one informant who was consistently accurate in naming objects and one informant who was consistently inaccurate. In condition 2 (Accurate–Neutral), a consistently accurate informant was included but the second informant made only neutral remarks (e.g. ‘Let me take a look at that’) that could not be easily evaluated for their truth. Finally, in condition 3 (Inaccurate–Neutral), a consistently inaccurate informant was paired with a neutral informant. Subsequently, in all three conditions, children’s relative trust in the two informants was probed via three different types of question. In Ask questions children were invited to ask one of the two informants for help regarding the names of unfamiliar objects. In Endorse questions, they were invited to agree with the name proposed by one or other of the two informants. Finally, in Explicit Judgment questions, they were asked to judge how good each informant was at answering questions. Note that Explicit Judgment questions were always asked at the end of the test procedure, following the Ask and Endorse questions. This was to eliminate the possibility that the experimenter’s invitation to make explicit judgments about the two informants would cue children with respect to whom they should ask and endorse. According to our favoured hypothesis, children should bring default trust to each unfamiliar informant but come to mistrust an informant who proves inaccurate. Hence, they should display selective trust in conditions 1 and 3, because in each of those conditions one of the two informants makes false claims. In condition 2 (Accurate– Neutral),