If you were a farmer and local wildlife were gnawing away at your crops, what would you do to fix the problem?

In 1958, Chinese leaders had just launched the Great Leap Forward, a movement that aimed to boost the economy through large industrial and agricultural changes. One of the first campaigns to be launched in this initiative was the Four Pests Campaign.

Leader Mao Zedong initiated the campaign after concluding that four pests – mosquitoes, flies, rats, and sparrows – were blighting crops and needed to be eliminated. Sparrows especially were blamed for their love of eating grain seeds.

With this conclusion, the population was called upon to kill these pests. Scarecrows and red flags were put up to frighten away the sparrows, while firing zones were set up for shooting sparrows.

One citizen recorded in his diary that people “banged [their] gongs, drums, washbasins, and anything else that could make loud noises. The sparrows were forced to keep flying until they dropped dead from fatigue.”

However, after thousands of sparrows were killed, the crops started dwindling, rather than increasing. By 1960, scientists discovered that sparrows’ diets were composed of three-quarters insects, and only one-quarter grains. So Mao replaced the sparrow with bed bugs on the list of four pests in hopes of improving the situation.

But it was too late.

Without sparrows around, locust populations multiplied and decimated the fields. Things became so dire that the government imported sparrows from the Soviet Union to fight the plague. The combination of locusts, pesticide misuse, and deforestation led to the Great Chinese Famine, in which over 30 million people died of starvation.

Actions Spark Reactions, But Not Necessarily the Ones We Expect

Whenever we perform an action to achieve an end, an outcome occurs. But the events that play out might not happen the way we expect them to. Just as killing off the sparrows led to a famine, a well-meaning act can result in a different result than anticipated. This is where the law of unintended consequences comes in.

The law of unintended consequences states that intervening in a complex system can create unforeseen outcomes, which may or may not be desirable. There are three types of unintended consequences that can happen:

An unexpected benefit: Also known as serendipity, an outcome can have an unexpected positive situation happen. For instance, ships that sank nearby coasts due to war or storms create artificial reefs. The reefs attract divers and fishing enthusiasts, which generates tourism revenue, along with valuable research for scientists (here are some photos).

An unexpected drawback: An action that creates the intended result can also have a negative side effect. Besides the failed Four Pests Campaign in China, alcohol prohibition in 1920s United States led many small alcohol suppliers to go out of business, leaving only large crime organizations. These organizations could supply alcohol and use increased funding for other illegal activities.

A perverse result: An action backfires, worsening the situation further. One example of this is the alcohol abstinence movement in 19th century Ireland, led by Theobald Mathew. While hundreds of thousands took the pledge not to drink alcohol, it led to the increase in consumption of diethyl ether, a much more dangerous chemical than alcohol, by those who didn’t want to break their pledge.

In many cases, we see that people are often surprised at the results of something they’ve done. Why couldn’t Theobald have seen the negative impact of his alcohol abstinence pledge? What causes an action, no matter how carefully planned, to lead to such unexpected consequences?

Why We Can’t Foresee the Outcome Beforehand

One reason why unintended consequences happen often is that we live in a complex world. When it’s difficult to account for all possibilities, many factors end up unconsidered. A seemingly small change can disrupt the balance and cause other parts of various systems (environmental, political, social, etc.) to shift as a result.

Besides the nature of the world we live in, unintended consequences are also due to human error and thinking. We can make misjudgments due to a lack of knowledge and research, or become blinded from overconfidence in our abilities. It can be hard to speculate how other people will behave and the impact of their reactions.

Other times, our emotions get the best of us. We often act based on immediate gratification rather than long-term benefits. Emotions, such as fear or anger, make it hard to think clearly and can lead to actions we later regret. They can create tunnel vision, causing us to achieve an end that might have undesirable effects.

Understanding a situation and giving yourself the time and resources to make the right decision can help you think clearly about the impact of various actions. There are always going to be unforeseeable situations, but gaining experience to deal with them is a strong step towards a favorable outcome.

How to Plan for Unintended Consequences

Here are three methods you can use to keep away unwanted results that might arise:

Historical analysis. Testing. Rational thought.

Let’s look at each of these methods in-depth.

Study similar events in the past. By learning about similar situations that happened before, we can become more aware of drawbacks and benefits. Just as we saw in the Four Pests Campaign, disrupting the ecosystem leads to an imbalance that changes the quality of our lives. We can use this information to study how one change might harm or help another part of the system.

Use a smaller sample size as a test. Before implementing something in an entire area, we can test it out in a small section to see the results first. Hospitals often use testing, known as pilot studies, as a way of testing out new technologies and care methods. If hospital care is improved overall as a result, then the changes are implemented in other hospitals as well.

Think it through. Making decisions purely on emotions can cloud our judgment after strong, temporary feelings subside. Sleeping on a decision can let you think it over and adjust if needed. For example, doing something quickly just to get it finished “for once and for all” can backfire if not done correctly, which ends up wasting more time and energy.

These methods can be applied at all levels, from decisions that affect large groups of people to ones we face in our personal lives. Here are the ways I’ve implemented these methods into my life:

Historical analysis: When I make a large decision, such as a financial investment, I learn about other people’s experiences to learn about intended and unintended consequences from doing something similar.

Pilot study: If I have a story that I think would be interesting to share, I might tell it to a few people first to get their feedback and responses first.

Rational thought: When I receive an important message that needs a response, I’ll wait at least a day before replying to make sure my reply has been thought through and comes out right.

Managing Our Lives in an Unpredictable World

There are always going to be restraints that prevent us from knowing the full consequences of our decisions. The limited time we have, our resource constraints, and the complexity of the world around us make unexpected events a natural part of life.

The important part is to stay mindful of all the possibilities that can result. Using the tools at our disposal, we can do what’s within our grasp to guard against undesirable outcomes. At the same time, we need to open ourselves up for serendipity.

What are some unintended consequences that you’ve experienced in your own life?