Narrator: This is Science Today. Research at the University of California, Irvine, found babies have some sense of reasoning about objects in the physical world. Gavin Huntley-Fenner, who led the study, says previous research found babies are surprised when one of two solid objects suddenly disappear behind a screen.

Huntley-Fenner: Folks took that to be about number. We looked at that question, to see whether those results have to do with number or whether they're due to something else.

Narrator: That something else may be reasoning. Huntley-Fenner altered the same test using sand, a non-cohesive substance.

Huntley-Fenner: We poured one pile of sand in front of them so they could see it, then we hid it and we poured another pile of sand in a different location. And then the screen came down and by magic, there was only one there. In that case babies didn't care if there was only one pile of sand. We wanted to argue that in a fundamental way, babies are like adults. That is, they divide the world into things that you will track as individuals and things that you won't try to treat as an individual.

Narrator: For Science Today, I'm Larissa Branin.