Baby's Brain in Week 33
By now, Baby has a firmer grasp on how the world gets around. She understands how people and animals move as compared to balls and toy cars. She's likely surmised that animate objects don't necessarily move in straight lines but may change direction without any obvious force acting upon them (although no, she doesn't get that whole "free will" concept yet). And she seems to understand that a person has the capacity to look like he is going to get a drink or water but then changes course and turns on the computer instead.
Babies at this age also are aware that inanimate objects—toys, for example—only change direction when an external force carries, pushes, or pulls them. Now, incredibly, they anticipate that the ball they're watching—which is about to bump into a table leg—will, upon impact, spin off in another direction. And that the toy car in front of them is going to reverse itself because it's quickly approaching a wall; when it hits the wall, Baby knows the force will make it go backwards. Here's how we know so much about babies' understanding of this movement.
What the Research Shows
In a research experiment, eight-month-old babies watched one of two videos. In the first film, a person stood next to a large box, which began to move on its own toward that person. The on-screen situation became even more preposterous as the box dodged the person standing near it, avoiding a collision. The babies looked at the screen for a long time, perplexed: If they could have spoken, they might have said, "How in the world did that happen? An inanimate box can't move on its own! And besides, it certainly can't move around a person—it should have bumped into it!"
In the second film, one person walked toward another person and then walked around him, avoiding a collision. The audience of babies didn't look quizzically at the screen: They knew that people (animate objects with the ability to control their own actions) can quite easily move around each other. If the two people in the film had crashed into one another, it would likely have surprised the babies. (And you and me, too!) We expect people to be able to prevent such incidents and we expect non-living, moving objects to bump, crash, and ricochet off each other.