Let's face it.

We're not very good at sharing. Give a group of people a collective  resource like drinking water, and some of us are bound to use it all  up leaving nothing for everyone else.

It's so ingrained in human  nature that this variety of selfishness has its own name:  The Tragedy of the Commons. We're motivated to do what's  best for us as individuals, even when we'll all ultimately suffer for it. For decades, the Tragedy was considered inevitable and became one of the most famous problems in the branch of mathematics called game theory.

But at the same time, a clever economist named Elinor Ostrom got interested in it. And on her way to solving it, she showed how we could address some of the  world's biggest troubles. [♪INTRO] If you know anything about Game Theory, it's probably that it drove the  nuclear arms race during the Cold War. That's because Game Theory deals with the strategies people use when making decisions.

If I have lots of nuclear weapons, you won't dare fire one of yours at me. But there's a lot more to Game Theory than was featured in the movie Dr. Strangelove.

One of the most famous concepts in the field is The Tragedy of the Commons. It highlights the conflict between what’s good for the individual and what’s good for everyone. In the Tragedy of the Commons, individuals tend to extract as much as they  can from a common resource, improving their own success to the detriment of everyone else with access to it.

But when everyone acts in  their own best interests, the common resource is destined to be depleted, leading to failure for the  entire group. The “Commons” is any shared resource, and its “Tragedy” is the inevitability of a poor  outcome for everyone involved. An ecologist named Garrett  Hardin was particularly concerned about humans’ shared use of  natural resources, and he coined the phrase in 1968.

Hardin  introduced the Tragedy of the Commons with the example of livestock  ranchers and a shared grazing field. Imagine you’re a new rancher with a  herd of 20 cattle in your first year. There’s a perfect grazing field nearby, and you and your neighbors all decide  to put your cows in the field.

At the end of the year, your  animals are very healthy and you’ve all made a nice profit! The next year, you decide to  add two cattle to your herd. More cattle equals more profit, so why not?

It’s a pretty straightforward conclusion… that your neighbors also realized. So that year, there are a  lot more cows in the field, causing it to become overgrazed. With less grass to go around, your  cattle are less healthy than before.

You make a slightly smaller profit  per animal, but the increased herd size means you still earn more  overall than the previous year. Now it’s time to decide on  the herd size for this year. A larger herd means less profit per  animal, but a greater profit overall.

So what number of cows optimizes the outcome? Don’t forget, your neighbors are all  making the exact same calculation. When Hardin proposed this scenario, he saw it as a ruthless and inescapable cycle.

He predicted individuals would get caught in the Tragedy of the Commons, and he saw very few options for doing anything about it. For decades, everyone who studied  game theory seemed to agree. People are selfish.

End of story. Then by the 1990s and early 2000s,  a political scientist and economist named Elinor Ostrom and her colleagues  got interested in the problem. Ostrom started her work as  a grad student in the 1960s, an era dominated by Hardin’s philosophies.

But as she read case studies about small communities across the globe, she quickly realized that people had been successfully regulating their use of common resources for centuries. And the most powerful tool in avoiding the Tragedy seemed to be communication. Thanks to Boot.dev for  supporting this SciShow video!

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And that’s before you even meet  Boots, the AI-powered Bear Wizard. You can get started with 25% off  your entire first year by going to Boot.dev, using the code SCISHOW,  and choosing the annual plan. As a grad student, Ostrom started  by observing her hometown: Los Angeles.

She studied  water usage across the city. And if you’ve never been to LA, it’s really dry. It’s often hot, and drinking water  is an important and limited resource.

She was specifically looking at  the organizational structures, like committees, usage  contracts, and legal action, that the communities used to  regulate their own water sources. Ostrom found that when individuals made decisions about how much water to take  without talking to each other first, they drew too much water  and depleted the resource. When everyone was making independent decisions, over-extraction could only  be penalized after the damage was done and everyone could see the consequences.

But by sharing information and  talking about their individual and collective needs from the  start, they devised a penalty system that could enforce withdrawal  limits before things got dire. Just by meeting face-to-face, communities were able to regulate the distribution of water, protecting the resource and  leading to a better outcome. It seems like such a simple solution  that it couldn’t possibly work!

But the time spent attending  meetings was totally worth the benefits gained by  protecting their shared resource. And, even better, Ostrom showed that communities are likely to choose  regulation over a free-for-all. People didn’t even need to  be forced to work together.

It was the first crack in Hardin’s cynical theory. But sometimes, communication isn’t enough. Take the example of shared spaces.

Ostrom studied how communities shared forests, oceans, and groundwater. But an example that’s closer to  home for many of us are the roads. It might seem weird to think of  roads as a depletable resource.

But when you’re making your morning commute, you’re using some of the space on the road. And if everyone decides the fastest  way to get to work is to drive their car, the road gets used  up and you have a traffic jam. Not only does this lengthen everyone’s commute, but it’s also super bad for the planet.

Personal cars are one of the leading contributors to greenhouse gas emissions, and car exhaust is a dangerous source of air pollution in cities. In the case of reducing  traffic, the government can create infrastructure, such  as public transportation, to help everyone share the roads. A single bus can take like 50 cars off the street, and a light rail or subway  has even higher capacity.

If public transportation is  a convenient enough option, more people are more likely to use it, helping clear up traffic for everyone. For example, long-term studies in London showed that when buses became more  reliable, people used them 40% more. And as a result, everyone on the road was able to get to their destination 30% faster.

So if enough people are able  to choose anything-but-a-car, then everyone benefits from faster commutes. As long as the infrastructure is convenient enough and affordable enough and just  generally enticing enough, it can help us avoid the Tragedy of the Commons. But we often need incentives, too.

Ostrom noticed that an important part of avoiding the Tragedy is enforceable  rules with reasonable penalties. She studied penalties and incentives in industries like lobstering in Maine. But, assuming that most people  watching this video aren’t lobsterers, there are other examples  that might be more relatable.

For example, fees or tax breaks can incentivize cutting down  on single-use plastic bags. As you may know, plastic  doesn’t biodegrade in landfills, and we’re running out of places to put it. So many US cities now require shops to charge a fee for single-use plastic bags, shifting some of the collective cost  of plastic back onto individuals.

And although it’s usually  only a few cents per bag, it’s so annoying to pay for bags  when you KNOW you have a bunch shoved under your kitchen sink that  you just keep forgetting to bring! So, not surprisingly, those fees have worked. Places that have implemented plastic bag fees— like Seattle, Santa Barbara, and Washington, DC— have cut their use in half!

Government organizations  across the globe are trying to use carbon taxes to make  corporations feel the same way about their emissions that you  feel about your grocery bags. And the Tragedy of the Commons  is not just about competition between individuals, but competition  between now and the future. Depletion of common resources today threatens our prospects in the next generation.

Right now, we’re facing the  consequences of centuries of over-extraction of everything  from water to fossil fuels. But Ostrom showed we can  still avoid the most tragic outcomes through communication  and self-governance. For that work, she received the  Nobel Prize in Economics in 2009.

There’s no single strategy that will help us manage every type of common resource. But the Tragedy of the Commons is not inevitable. We can use our resources sustainably when we decide on strategies together. [♪OUTRO]