Anyone who knows toddlers knows this is a GAME.
Experimenter: "That's a bear." Toddler "Nooo it isn't, it's a bottle!" (Laughter)
You can bet the experimenter gave the whole thing away with lots of play-face expressions as well. The toddler probably trusts both speakers, but are expecting one of them to carry on fooling around.
I think it's more than just that simple game:
...Indeed, 4-year-olds monitor apparent differences in reliability even when no obvious errors are involved. Having watched one informant name objects accurately and another informant make non-committal remarks about them (e.g., “Let me look at that”) or express ignorance, children subsequently invested more trust in the accurate as opposed to the non-committal informant (Corriveau, Meints & Harris, 2009) or the ignorant11 informant (Koenig & Harris, 2005). Fourth, reliability monitoring can reverse the n
From "Trust in testimony and miracles":
See also:
Cognitive Style Tends To Predict Religious Conviction