At first glance, the maroon Douwe Egberts coffee machine at the O.R. Tambo International Airport in South Africa looks pretty normal. On close inspection, it’s missing something important. There’s no place to put money. The only currency the machine deals in is yawns.
Facial-recognition software built into the machine looks for people standing in front of it. It maps their faces and waits for the telltale signs of a yawn. A yawn triggers a hot cup of coffee.
The international coffee company chose the airport as a prime place full of weary passengers and plenty of yawning. Over the course of the marketing stunt, the machine reacted to 210 yawns, doling out the caffeinated antidote by the cup.
With more than 2.25 billion cups enjoyed worldwide every day, coffee is the planet’s single most valuable traded food commodity.
Coffee’s effectiveness as high-performance brain fuel makes it liquid gold, and it’s not surprising that coffee’s primary active ingredient, caffeine, is the globe’s most commonly used psychoactive drug. The connection between caffeine’s main botanical source – the coffee plant – and our own biochemistry is one of nature’s best hacks.
“The fact is that 85% of the U.S. population consumes caffeine every single day,” says Sally Greenberg, the National Consumer League’s executive director. “And while we know where to find it, and [we] consume a lot of it, the majority of Americans are not ‘caffeine literate.’”
Ironically, the world’s favorite stimulant is actually the coffee plant’s defense mechanism. Caffeine’s bitter taste is meant to deter hungry herbivores, pests, and disease. It’s also a “no trespassing” sign to other territory-stealing plants.
Some animals can get over the bitter taste, though, and those that do tend to love both coffee and caffeine. Humans are a great example. Interestingly, so are bees. The bees get a stimulant effect from caffeine that’s similar to the one you experience. The bees love it, and it works well for the coffee plant, too: bees pollinate coffee plants like crazy.
Recent research shows that the coffee plant uses a different set of genes to produce caffeine from those found in tea, cacao, and other such plants. Science suggests that coffee and tea shared a common ancestor 100 million years ago. Since then, each has evolved to produce caffeine in a very different way. It’s clear that the coffee plant was caffeine’s favorite – coffee has twice as much caffeine as tea does.
Your brain on caffeine
When caffeine hits the brain it suppresses a neurotransmitter called adenosine. Adenosine influences attention, alertness, and sleep. It builds up in your brain as the day goes on, like mercury rising in a thermometer. When adenosine hits a certain level, your body decides it’s bedtime. You have trouble staying awake and paying attention. When you sleep, adenosine resets, the thermometer drops back to zero during the night, and you wake up in the morning alert and ready to go.
Caffeine competes with adenosine. It binds to certain receptors in the brain like a key fitting into a lock. If caffeine is in the lock, adenosine can’t bind, and it can’t make you sleepy. By blocking adenosine, caffeine keeps the cell running, and keeps you awake.
When caffeine blocks adenosine, stimulating brain chemicals like glutamate and dopamine join the party and flow more freely — giving you a surge of energy, improving mental performance, and slowing age-related mental decline. Caffeine also increases serotonin, a major mood influencer. The boost makes you feel more positive, and it’s strong enough to measurably affect depression. That’s right: a morning cup of coffee can make you a happier person.
Studies also show that caffeine improves learning by up to 10%. Caffeine can even relieve headaches and migraines by constricting blood vessels in the brain that are opening too wide. That makes drinking coffee one of the easiest brain performance hacks ever.