This is Hidden Brain. I'm Shankar Vedantam. It seems like the simplest choice in the world.

Given the option between pain and pleasure, we ought to choose pleasure. Is it better to be

hungry or full? Better to be tired or alert. Better to watch another episode of our favorite

TV show or do the dishes.

It isn't just our own minds that tell us to choose the path of enjoyment and indulgence.

Our friends remind us that life is short. Say no to dessert or another round of drinks,

and someone might call you a spoil sport.

At Stanford University, psychiatrist Anna Lemke has heard the same messages.

But as a scientist, she's also studied the way our brain's balance, pain and pleasure.

The two sit on opposite ends of a neural seesaw, and the brain

constantly attempts to bring them into equilibrium, or what is known as homeostasis. When we press down

hard and often on the pleasure side of the seesaw, triggering bursts of the neurotransmitter

dopamine, Anna says the brain automatically

compensates by pressing down on the other side, producing a dopamine deficit.

Over time, as people press down too much or too often on the pleasure side of the equation,

the brain compensates so forcefully that we start to walk

around with a chronic dopamine deficit. This can manifest as anxiety, irritability, and depression.

There is complex neurochemistry behind the process of homeostasis, but Anna has come up with a simple way to visualize this.

When you press down on one side of the seesaw, imagine a bunch of gremlins inside your head jumping on the other side of the seesaw.

We explored how this mechanism works and why it exists in our previous episode.

If you missed it, I strongly suggest you listen to it first.

Today, we continue with the second part of our story about the paradoxical effects of pleasure,

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