Physics is a tough subject. The laws are complex, the mathematics involved even more so. Still, these laws can be verified. And they can often predict the outcomes pretty accurately. For instance, by referring to Boyle’s law, one can predict that the pressure of a confined gas will decrease as the volume of the container increases. According to Newton’s first law of motion, a body (mass) at rest will remain at rest, and a body in motion will continue to be in motion, unless it is acted upon by an external force. These laws are generally taken as a given. There are no unanticipated outcomes to any of these laws (thankfully).

Things start to get messy when you add human behaviour to the equation. We’ve all been through this. Something happens, and you expect people to react a certain way. But they don’t. In fact, they may behave in a completely different way from what you anticipated.

This happens so often that this phenomenon has been designated its own law: the law of unintended consequences. The law refers to how decisions or purposeful actions can lead to unforeseen effects.

Generally speaking, unintended consequences could lead to unintended benefits, unintended drawbacks or perverse results.

Unintended benefits:

Commonly known as luck or serendipity, these occur when a positive unintended effect takes place along with the desired effect of the action. Here, a famous medications come to mind. The drug Viagra’s initial purpose was to lower blood pressure, with its use for treating erectile dysfunction discovered during clinical trials. Other studies have shown that prompting guests to reuse hotel towels not only makes them more likely to reuse their towels, but more likely to carry out other environmental-friendly behaviours such as switching off their bedroom lights.

Unintended drawbacks:

Sometimes referred to as collateral damage, these occur when an unexpected side effect occurs along with the desired effect of the action. For instance, a field experiment revealed that individuals who received regular feedback on their household water use managed to decrease it, but have increased their electricity consumption. A more recent example has to do with COVID. During the pandemic, non-COVID related morbidity and mortality rates have increased partially as a result of lockdowns and stay-at-home orders.

Perverse results:

Also known as the boomerang effect, perverse results occur when solutions backfire. For example, an eating disorder support group for women involved many of them describing their harmful eating habits, causing participants to report even more eating disorder symptoms. The British government, in an attempt to curb the number of venomous cobras in Delhi, offered a financial reward for every dead cobra. This incentivised individuals to breed cobras for the income, and then setting them free when the government scrapped the reward program. This caused an even more drastic increase in the wild cobra population.

Final thought:

At the end of the day, unintended consequences are a sobering reminder that humans have blind spots when making decisions. Thinking holistically and planning carefully will sometimes succumb to failures of foresight. Still, this should not deter us from trying to make changes in our life and our surroundings.

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Behavioural science