Why we don't juggle as well as we think

A growing body of studies suggests that juggling several activities at once may be less valuable than many people assume.

The reason, researchers say, is that the brain can effectively perform only one difficult task at a time. A Michigan professor found that when someone tried to multitask, important neural regions must switch back and forth, taking time and creating inefficiencies.

UCLA researchers used brain imaging to show that multitaskers were less effective learners. According to that research, a person focused on a single task remembers what he has learned using the hippocampus, a part of the brain critical to storing and recalling information.

But when that person multitasks — like trying to learn something new while driving — the brain relies more on the striatum, a part of the brain used more for learning motor skills.

The researchers concluded, “Don’t multitask while you are trying to learn something new you hope to remember.”

“The brain is fundamentally built to unitask,” says Clifford Nass, a communications professor at Stanford.

And here's another sobering thought. Research shows that the brains of heavy multitaskers can become so accustomed to hopping from task to task that they have trouble focusing on longer, more in-depth ones.