Unintended consequences

Unintended consequences are surprising results that happen when we take action, but we didn’t plan for them to occur. In the social sciences, this idea was popularised in the 20th century by American sociologist Robert K. Merton. Sometimes these results can be good, like finding something helpful we didn’t expect. Other times, they can cause problems, like when an action meant to help ends up making things worse in another way.

For example, when irrigation schemes give people water for farming, they can also lead to waterborne diseases like schistosomiasis, which harm health. These surprising outcomes are called unintended consequences because they are not what we planned for when we started our action. Understanding them helps us think more carefully about what might happen when we try to solve problems.

There are three main types of unintended consequences: unexpected benefits, unexpected drawbacks, and results that are the opposite of what we wanted. These can happen in many areas of life, from science to politics, and they remind us that actions can have many different effects, some of which we might not see right away.

History

The idea of unintended consequences goes back a long way. John Locke talked about how trying to control interest rates can lead to results that were not planned. Later, Adam Smith from the Scottish Enlightenment also looked at this idea. He talked about how people trying to do what’s best for themselves can end up helping the whole economy grow, even if that wasn’t their plan. This is known as the invisible hand theorem.

In the 1800s, writers like Friedrich Engels and Karl Marx thought about how people’s plans can clash and lead to results that no one wanted. They believed that even when people act on purpose, the outcome can still be surprising.

In the 1900s, Robert K. Merton became famous for studying unintended consequences. He looked at how plans to change society can sometimes lead to unexpected results. Today, people often use the idea of unintended consequences to remind us that trying to control everything can backfire in surprising ways.

Causes

Sometimes, things we do can lead to results we didn't plan for, because the world is very complicated and everything is connected. Small changes can cause big effects, like how a butterfly flapping its wings might change the weather far away.

In 1936, a sociologist named Robert K. Merton suggested five reasons why this happens: not knowing everything, making mistakes in planning, focusing only on short-term goals, values that affect our choices, and acting to prevent a problem before it happens, which can change what actually occurs. Another reason, noted by psychologist Stuart Vyse, is when groups make decisions without thinking enough about different ideas.

Types

Unexpected benefits

Sometimes, when we do something to solve a problem, we might get an extra good thing we didn’t plan for. For example, during the Cold War, places like the border between Eastern and Western Europe and the Korean Demilitarized Zone became home to many plants and animals because they were left alone. Also, when ships sink in shallow water, they can create special homes for sea creatures, which scientists can study and people can visit while diving.

In medicine, some medicines have helpful side effects. Aspirin, which is used for pain, can also help prevent heart attacks. Another medicine, Viagra, was first made to help with blood pressure but was later found to help with a different health problem.

Unexpected drawbacks

Sometimes, when we try to fix something, we might cause another problem we didn’t see coming. For example, when Australia made bike helmets required by law, fewer young people wanted to ride bikes because they thought helmets were not cool. This meant fewer kids were riding bikes, which could be bad for their health.

In the 1920s, the United States tried to stop people from drinking alcohol. But this just made organized crime groups stronger because they sold alcohol secretly. Similarly, efforts to stop illegal drugs sometimes make drug groups richer and more powerful.

Some animals brought into new places to help with problems became big pests instead. For example, rabbits brought to Australia for food multiplied too much and caused damage. Cane toads brought to Australia to eat pests also became a problem.

Perverse results

Sometimes, trying to stop something can end up making it more famous or worse. For example, when a famous person tried to stop a photo of their house from being shared online, it just made more people see the photo.

There have been cases where rewards for doing good things led to bad results. For example, when a city offered rewards for killing snakes, some people started breeding snakes just to collect the rewards. When the rewards stopped, these snakes were let go, making the problem worse.

Other

Sometimes, new inventions can change how people live in big ways. For example, the invention of the stirrup for horses changed how wars were fought and helped create new ways of organizing societies.

Perverse consequences of environmental intervention

Many environmental problems, like pollution and global warming, happen because of new technologies we use. For example, cars cause traffic jams, accidents, air pollution, and even help warm the planet. Using antibiotics can lead to stronger germs that make people sick, and new ways of farming and industry can cause more people to be born, which hurts the environment.

Because nature is very complicated, when we try to change it, we often get results we didn’t plan for. These changes can sometimes be permanent and harmful. For example:

• In China a long time ago, leaders tried to get rid of birds and other pests. This worked, but without birds eating them, lots of harmful insects grew too big and ate crops, which hurt food supplies.
• In London, leaders once tried to stop a sickness by killing dogs and cats. This removed animals that could have helped control the rats that spread the sickness.
• Putting tall chimneys in factories helped keep pollution away from towns, but it spread the pollution higher into the sky, causing rain with acid far away.
• In the United States, leaders tried to stop forest fires by putting them out quickly and protecting forests. This helped stop small fires, but when big fires happened later, they were worse because the forests had grown thicker. Now we know that small, natural fires help keep forests healthy.
• Trying to slow down global warming by changing how we use land could sometimes make the planet even warmer instead.