The brain chemical dopamine, associated with reward and motivation, is very different from serotonin, associated with contentment and true happiness.

You can't get contentment from an app or from a purchase, but you can click or buy your way to a whole lot of reward and pleasure.

The language difference between "happiness" and "pleasure" is subtle, but the chemical difference is huge. These chemicals are the reason why our phones can feel addictive.

This is an installment of Business Insider's "Your Brain on Apps" series that investigates how addictive apps can influence behavior.



People trying to sell you a new car, a fancy phone, or a bigger home might like you to believe that money can buy a whole lot of happiness. But your brain knows that's not true. Money can buy you pleasure, but happiness has to come from somewhere else.

If you're confused between happiness and pleasure, you're not alone. After all, we've been conditioned to believe that happiness comes from buying that new thing, satisfying that food craving or being in on the latest trend.

Even the dictionaries and search engines get a little confused: If you Google "pleasure" the first definition that pops up is "a feeling of happy satisfaction and enjoyment."

But scientists who study hormones say our brains can tell the difference between a quick rush of pleasure and the long-lasting contentment that is the true definition of happiness. And it's a big one.

"If you've been told your entire life that pleasure is happiness, then, you know, you're screwed," Robert Lustig says.

Lustig's an endocrinologist, and author of "The Hacking of the American Mind: The science behind the corporate takeover of our bodies and brains." He was one of the first to study the effects of refined sugar consumption on kids, and now he's worried that tech could be working on our brains in similar, near-addictive ways. He says tech is not quite like a drug, but it feeds a potentially dangerous system of motivations and rewards in our brain, leaving us craving another hit.

"Technology is a dopamine stimulator," Lustig told Business Insider. "Anything that causes dopamine to rise has, as its end point, addiction."

That's not to say that tech works on our brains exactly like an alcohol or drug problem, because with tech, as far as we know, there are no visceral withdrawal symptoms, like jitteriness or headaches, if you turn off your phone.

Still, there is a dependence we've developed to our phones that is different from a feeling of contentment or calm peace.

That buzzing brick in your pocket? It's fueling the release of more stress hormones, and our brain's pleasure and reward-related chemical, dopamine.

It turns out that dopamine touches very different areas of our brain then serotonin, which we know is involved in decreasing anxiety and counteracting depression. Serotonin is so closely related to happiness that it's one of the key ingredients in many antidepressant drugs.

Take a look at the difference between how happiness-related serotonin and reward-related dopamine circulate in the brain:

As you can see in the above graphic, serotonin spreads happiness signals out to many different parts of the brain, touching at least 14 different receptors. Scientists like Lustig think this is part of the reason why happiness can be felt in so many different ways: sensations of joy, love and contentment might be sparked during different interactions serotonin has with receptors in different parts of the brain.

Dopamine, on the other hand, only has five brain receptors. The neurotransmitter interacts with those receptors to fuel feelings of desire and motivation. Dopamine is involved in regulating many things in our brains: rewards, motivation, pleasure, there's even some evidence it's involved in healthy hallucinations. But because it fuels a cycle of motivation and reward, it will never make us truly happy or content, feeling like we have enough and we are enough.

Instead, our phones have been built to leave us always craving more. They're not inherently bad, but it is something that we should all be aware of.

The only antidote? To put away our phones, limit the alerts they send us and share time with others, instead of constantly staring at our screens.