In three experiments, children aged between 3 and 5 years (N = 38, 52, 94; mean ages 3-7 to 5-2) indicated their confidence in their knowledge of the identity of a hidden toy. With the exception of some 3-year-olds, children revealed working understanding of their knowledge source by showing high confidence when they had seen or felt the toy, and lower confidence when they had been told its identity by an apparently well-informed speaker. Correct explicit source reports were not necessary for children to show relative uncertainty when the speaker subsequently doubted the adequacy of his access to the toy. After a 2-min delay, 3-4-year-olds, unlike 4-5-year-olds, failed to see the implications of the speaker's doubt about his access.

In three experiments children aged between 3 and 5 years (N = 38; 52; 94; mean ages 3;7 to 5;2) indicated their confidence in their knowledge of the identity of a hidden toy. With the exception of some 3-year-olds, children revealed working understanding of their knowledge source by showing high confidence when they had seen or felt the toy, and lower confidence when they had been told its identity by an apparently well-informed speaker, especially when the speaker subsequently doubted the adequacy of his access to the toy. After a 2-minute delay, 3-to 4-year olds, unlike 4-to 5-year-olds, failed to see the implications of the speaker's doubt about his access.Working understanding of knowledge sources 3 Children's Working Understanding of Knowledge Sources: Confidence in Knowledge Gained from TestimonyThe ability to recall or infer how we know something is crucially important for assessing the accuracy of our knowledge (Johnson, Hashtroudi & Linsday, 1993).Suppose a companion on a country walk reports spotting an unusual bird that I failed to notice. I have no reason to doubt her, and so I believe that this particular bird was indeed in the area. However, that evening my companion mentions that she was not wearing her glasses on the walk. If I recollect that she was the source of my belief about the bird's presence, I might now be less sure of its truth: I thought she had seen the bird adequately to identify it and differentiate it from a more common variety, but now I find that she had not. In contrast, if I do not recollect how my belief was acquired, I will draw no such implication from her comment about the missing glasses. I will continue to treat my belief as factually true. Importantly, this kind of source-identification and evaluation allows adults to keep a check on the likely truth of their knowledge even in the absence of contradicting information. Note that in this example I had no independent information that the bird was not present, but nevertheless I had good grounds for reducing my confidence in my belief that it was.The need to engage in such source identification and evaluation arises early in childhood. As children's mastery of language increases, they need skills to assess the likely truth of what they are told in order to benefit fully from other people's experience of the world. This holds not just at the time of originally hearing an utterance, but also, as in the example above, subsequently, once the information conveyed has become part of their own knowledge base. Without such skills, children will be at risk of believing what is false or disbelieving what is true. Working understanding of knowledge sources 4In the research reported below we examined how 3-to 5-year-old children behaved in circumstances similar to the example above. A speaker appeared to have seen a hidden toy before telling the child its color, or to have felt before telling the child whether it was hard or soft. After the child believed what she was told, the speaker doubted that he had felt or looked properly...

We argue that, amongst 3- to 5- year-olds, failure to report the source of knowledge recently acquired in answer to “How do you know…?” is due to a specific failure to make a causal inference, in line with source monitoring theory but not fuzzy trace theory. In three Experiments, children (N = 37; 30; 59) identified a hidden toy by seeing, feeling, or by being told, having had two modes of access on each trial, one informative (e.g. seeing a toy identified by colour) and the other uninformative (e.g. being told the toy’s colour by the Experimenter who had only felt it). Children who answered the know question wrongly nevertheless reported accurately who saw and who felt the toy, and what the well-informed player had said. They also realised when\ud the Experimenter’s uninformative access implied their own knowledge was unreliable, suggesting precocious working understanding of knowledge sources