What if it were marijuana’s medicinal qualities that originally inspired humans to light up, instead of the urge to get high? That’s the theory of some Washington State bioanthropologists just back from studying one of the world’s last hunter-gatherer societies—nomadic Africans in the Congo Basin who also happen to be among the world’s biggest pot smokers.

What’s clear is that the Aka people are managing to keep at bay an otherwise deadly infestation of intestinal worms entirely through diligent application of cannabis.

They are not doing it on purpose, however. The Aka, also known as Pygmies, enjoy weed because of what it does to their heads, not their intestines. A 1977 study of the group described its use as motivational: They “smoke to increase their courage on a hunt, dance better, increase their vital force, or to increase their work capacity when working for Europeans or village people,” researcher Barry Hewlett wrote at the time.

This next generation of Congo researchers, led by Washington State University researcher Ed Hagen, found the same. And then they deduced that the health benefits of enjoying a leaf-wrapped spliff in a Central African rainforest are evolutionary. The Aka may be unconsciously self-medicating.

This goes way beyond pot and Pygmies. Hagen thinks human use of all plant-based drugs followed the same path.

“We might have evolved a ‘taste’ for drugs for some utilitarian reason, such as defense against parasites,” Hagen said by email, “but then we elaborate this behavior in rituals, etc., exactly as we do for eating food and every other utilitarian behavior.

“Countless rituals have developed around food that do not relate to nutrition. The same goes for sex, clothing, shelter and other utilitarian behaviors. All these behaviors are (and were) essential to survival and reproduction, but we humans have a tendency to elaborate everything. We think the same might be true of recreational drugs.”

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That would mean that in the Aka’s ongoing battle with worms, pot is “instrumental.”

The term was coined in 2011 by psychiatrist Christian P. Mueller to describe the way that people learn to take drugs for purposes other than to get stoned. “Humans are able to learn that mental states can be changed on purpose by drugs, in order to facilitate other, non-drug-related behaviors,” Mueller wrote in the journal Behavioral Brain Science.

The drugs-as-instruments idea is a shift from the usual way of seeing drug use as a mark of human failure, whether as a step toward addiction or a purely Bacchanalian compulsion. Mueller argues that drug use should also be viewed as “a stable and widespread behavior in its own right,” at least among people who don’t get addicted—and Mueller frequently points out that most drug takers don’t.

You already know about instrumentalization: People take psychoactive drugs all the time with a specific goal in mind other than sheer fun, whether it’s to stay awake for a long drive, achieve special insights during a religious ritual or even just relax after work.

Skeptics abound. “Do drugs really allow us to cope with ‘modern’ (read: shitty/stressful) environments? Or is drug (ab)use the consequence of these environments?” asks one poster on a Bluelight web forum page about Mueller.

But the idea hits home for lots of people, even those who know from drugs’ bad side. Another participant in the same Bluelight forum wrote this: “i have been dependent on substances at times, but even having been thru that, i'd still choose to use the ‘instruments’ to expand my reservoir of experiences.”

Some harm reduction websites link to Mueller’s work. If drugs do have a rightful place in human society, as the argument goes, then the criminal justice and abstinence approaches to addiction need amending.

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Mueller is not ignoring drug abuse. On the contrary, he says, “Understanding the everyday utility and the learning mechanisms of non-addictive psychotropic drug use may help to prevent abuse and the transition to drug addiction in the future.”

He thinks it’s the way we form memories that holds the key to drug use of all kinds. Some of these are good memories and others bad: Psychoactive plants are technically a kind of toxin, which is why people generally experience drugs as bitter or otherwise unappealing at first.

In a 2013 journal article, Mueller quoted a friend to show how the memory process works:

“I smoked my first cigarette when I was 12 years old – behind the house, together with a few friends and some older guys who had provided it for trying. It was incredibly cool, not allowed of course, and it tasted awful. Despite persistent peer pressure, the memory of this one event still accompanies me until present day. It forms part of my personality and prevents me from trying cigarettes again. My first experience with alcohol a little later at the retirement party of my much beloved granddad was quite bad as well. I felt sick and abstained from any countable consumption of alcohol for a few years. However, when I was a student I felt forced to social drinking which I tentatively did. At one occasion, however, I learned from rather unexpected feedback that my constitutively restricted social skills were tremendously enhanced after a few glasses of wine. This one episode, again vividly remembered to the present day, has shaped my drug consumption behavior into another direction. After establishing a working dose window, I can now ‘instrumentalize’ a controlled consumption for just this one purpose: ‘socializing on demand.’"

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The Aka make good subjects for researching instrumental drug use (at least the unconscious intestinal health kind) because they don’t have access to sophisticated health care. And that’s the way things were for humans during 99% of our time on the planet. We have been evolving our drug needs and tastes for hundreds of thousands of years.

It’s also possible that plants have been doing the same.

Indeed, Ed Hagen believes that humans and the plants we smoke, snort or shoot up may have “coevolved.” He thinks this is why drugs are able to mimic human brain chemicals like serotonin and dopamine and why humans are able to exploit these plants for our own assorted purposes.

It’s a slippery slope from the idea of human-drug co-evolution to the wacky views of people like Terence McKenna, who theorized that the mind-expanding power of magic mushrooms helped advance our ancestors beyond apes. Or consider Ronald K. Siegel’s idea that drugs are a biological need. He says pursuit of drugs is a basic human drive, the “fourth drive” along with food, water and sex.

But who’s to say, in the era of designer drugs and cheddar cheese Weed-Itz pot snacks, where our long and lively relationship with plant toxins will take us next?