How do people know?

To fully understand processes of knowing and knowledge acquisition, it is n ecessary to examine people's understanding of their own knowing. Individual and developmental differences in what it means to know something, and henc e in the criteria for justifying knowledge claims, have potentially wide-ra nging implications. In providing support for a claim, young children have d ifficulty differentiating explanation of why a claim makes sense and eviden ce that the claim is true. Epistemic understanding progresses developmental ly, but substantial variation remains among adults, with Sew adults achievi ng understanding of the complementary strengths and weaknesses of evidence and explanation in argument. Epistemic understanding shapes intellectual va lues and hence the disposition (as opposed to competence) to exercise intel lectual skills. Only its most advanced levels support a disposition to enga ge in the intellectual effort that reasoned argument entails. The sample ca se of juror reasoning illustrates how epistemic understanding underlies and shapes intellectual performance.