Law of Unintended Consequences

The law of unintended consequences was first mentioned by British philosopher John Locke when writing to parliament about the unintended effects of interest rate rises. However, it was popularized in 1936 by American sociologist Robert K. Merton who looked at unexpected, unanticipated, and unintended consequences and their impact on society.

Understanding the law of unintended consequences

The law of unintended consequences posits that any action has outcomes that are not intended or anticipated by the actor.

Merton noted that these consequences could be construed as positive or negative with the desirability of either based on context.

While rooted in societal impact, the law of unintended consequences is relevant to almost any scenario but is commonly associated with economic decisions, government policy, disasters, and the environment.

The three types of unintended consequences

The three types of unintended consequences are described below.

1 – Unexpected drawbacks 

These are undesirable consequences that occur at the same time as those deemed desirable. 

When the US government developed its freeway network in the 1950s, rail as a transport option became overlooked in favor of road transportation.

Car ownership reached such an extent in the 1990s that heavy traffic forced many to look at rail transport, but the infrastructure wasn’t there to meet demand.

2 – Unexpected benefits 

Otherwise referred to as serendipity or luck. When the Korean Demilitarized Zone was created it preserved a tract of forest habitat for native wildlife.

Aspirin, developed to be a pain reliever, was discovered to have anticoagulant properties that lowered the risk of a heart attack.

3 – Perverse results 

Perverse results are consequences that are contrary to the original intention. In other words, when a solution exacerbates the problem.

When vehicle manufacturers introduced airbags as a safety feature in the 1990s, they caused an increase in mortalities among children who were hit as the airbag deployed in a collision.

What causes unintended consequences?

In his work, Merton discovered five core reasons for unintended consequences:

  1. Mistakes, no matter how simple, can hinder the accurate prediction of an outcome. These mistakes result from a lack of knowledge of a specific situation.
  2. The assumption that repeating past actions will produce the same results in the future.
  3. Rushed or hastily considered actions based on the need for an immediate solution.
  4. Actions stemming from what Merton calls “basic values”. These are pervasive, entrenched beliefs, norms, and values that prevent proper consideration of the impact of an action on individuals or society.
  5. The self-fulfilling prophecy. This is a term Merton coined to describe a scenario where an incorrect definition of the situation evokes behavior that causes the original false conception to come true.

Key takeaways:

  • The law of unintended consequences posits that any action has outcomes that are not intended or predicted by the actor.
  • The three types of unintended consequences are unexpected drawbacks, unexpected benefits, and perverse results.
  • American sociologist Robert K. Merton believed there were five core drivers of unintended consequences. Chief among these is the notion that mistakes due to ignorance can skew outcome predictions and the assumption that past actions will produce the same results in the future.

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