Ira Glass

go to thisamericanlife.org slash lifepartners.

That link is also in the show notes of this episode.

And happy Valentine's Day.

This American Life, Act One, Baby Scientists with Faulty Data.

Fifty years ago, psychologists and scientists believed that babies could not think at all, that they were irrational and illogical, self-centered little balls of need and want.

What science has learned is that this is not true, that children are observing the world and thinking about it and coming to logical conclusions from the day they're born.

When Alison Gopnik and two of her colleagues decided to summarize a lot of this research in a book, they called it The Scientist in the Crib, meaning that babies are like little scientists.

They argue that when a small baby sits in a high chair and drops a spoon onto the floor over and over and over for mom or dad to pick up, what the baby is doing essentially is running a little baby-sized experiment.

Because it turns out that babies are very interested in gravity and how gravity works.

The fact that things fall down and not up is not obvious to babies.

While kids think with the same logic that adults use and apply that logic just as rigorously, there are certain things that they simply do not know and take a while to figure out.

Up to six or seven years old, for instance,

it's not exactly clear to anyone what is imaginary and what is not, or if wishing for something can make it come true.

Then the researcher would walk out of the room, leaving the box behind with the child.

And then something funny would happen.

The kids who were told to imagine a puppy in the box would go over and peek inside the box just to check.

And the kids who were told that there was a monster in the box, they would edge away from the box.

When they're still small and inexperienced about what happens in the real world...

children have to make logical inferences all the time based on the data that they do have.

Here is how children responded when our producer Jonathan Goldstein asked them about the tooth fairy.