Imagining what might be: why children underestimate uncertainty.

Children's well-documented tendency to behave as if they know more than they do about uncertain events is reduced under two conditions: when the outcome of a chance event has yet to be determined and when one unknown outcome has occurred but is difficult to imagine. In Experiment 1, in line with published findings, 5- and 6-year-olds (N=61) preferred to guess the unknown location of a known object when the object was in place rather than before its location had been determined. There was no such preference when the object's identity was unknown. In Experiment 2, 29 5- and 6-year-olds were more likely to correctly mark both possible locations when an already hidden object's identity was unknown rather than known. We conclude that children's vivid imaginations can lead them to underestimate uncertainty in a similar way to imagination inflation or fluency effects in adults.

Agency affects adults', but not children's, guessing preferences in a game of chance.

Adults and children have recently been shown to prefer guessing the outcome of a die roll after the die has been rolled (but remained out of sight) rather than before it has been rolled. This result is contrary to the predictions of the competence hypothesis (Heath & Tversky, 1991 ), which proposes that people are sensitive to the degree of their relative ignorance and therefore prefer to guess about an outcome it is impossible to know, rather than one that they could know, but do not. We investigated the potential role of agency in guessing preferences about a novel game of chance. When the experimenter controlled the outcome, we replicated the finding that adults and 5- to 6-year-old children preferred to make their guess after the outcome had been determined. For adults only, this preference reversed when they exerted control over the outcome about which they were guessing. The adult data appear best explained by a modified version of the competence hypothesis that highlights the notion of control or responsibility. It is proposed that potential attributions of blame are related to the guesser's role in determining the outcome. The child data were consistent with an imagination-based account of guessing preferences.

Children's sensitivity to their own relative ignorance: handling of possibilities under epistemic and physical uncertainty.

Children more frequently specified possibilities correctly when uncertainty resided in the physical world (physical uncertainty) than in their own perspective of ignorance (epistemic uncertainty). In Experiment 1 (N=61), 4- to 6-year-olds marked both doors from which a block might emerge when the outcome was undetermined, but a single door when they knew the block was hidden behind one door. In Experiments 2 (N=30; 5- to 6-year-olds) and 3 (N=80; 5- to 8-year-olds), children placed food in both possible locations when an imaginary pet was yet to occupy one, but in a single location when the pet was already hidden in one. The results have implications for interpretive theory of mind and "curse of knowledge."