This is Hidden Brain. I'm Shankar Vedantam.

About a century ago, the Swiss psychiatrist Carl Jung was treating a young woman.

He sat with his back to a window, listening to his patient.

She told him about a dream she'd had.

In it, she was given a piece of jewelry, modeled after a beetle,

long considered sacred in Egyptian culture.

The scarab beetle was associated in ancient Egypt

with a divine force that moved the sun.

Intricately carved scarab jewels

was sometimes placed on the hearts of the dead

to assist them in the afterlife.

The young woman told the psychiatrist

that in the dream, she was given a golden scarab.

As Jung listened to the story,

he heard a tapping behind him.

He turned to see a flying insect knocking against the window pane.

It was a beetle. In a monograph on what he called synchronicity, Carl Jung wrote, I opened the window

and caught the creature in the air as it flew in. It was the nearest analog to a golden scarab

that one finds in our latitudes, a scarab-beard beetle, which contrary to its usual habits,

had evidently felt an urge to get into a dark room at this particular moment. Scientists have

debated Jung's theory for decades.

Many have argued that what happened in that room was nothing more than an interesting

...