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Evolutionary Psychology

The Evolutionary Psychology of Murphy's Law

Why thinking that “everything that can go wrong will go wrong” is adaptive.

Key points

  • Murphy's Law, or the idea that anything that can go wrong will go wrong, is a common social-perceptual bias.
  • In everyday life, assuming worst-case scenarios has both benefits and costs.
  • From an evolutionary perspective, assuming the worst may well actually be quite adaptive.
Alexas_Fotos / Pixabay
Alexas_Fotos / Pixabay

So picture this: Dinner is done and I offer to clean up. About half the chicken and split pea soup (which was really good, by the way!) is left. In the spirit of getting the tough stuff out of the way, I figure I'll start by putting that in a Tupperware. I choose a round Tupperware that I think is plenty large enough for the amount of leftover soup.

As Murphy's Law (which is pretty much the maxim that anything that can go wrong will go wrong) would have it, there was about an eighth of a cup of soup more than was appropriate for the size of the Tupperware. In other words, my Tupperware was not quite big enough. As (bad) luck would have it, that extra eighth of a cup of soup landed pretty much all over the kitchen counter and floor. Let's just say the cleanup ended up being a larger job than was initially expected. "Figures," I thought to myself. "Murphy's Law..."

The idea of assuming the worst as a general psychological strategy in life—in other words, adopting the idea of Murphy's Law—is actually, when we think about things from an evolutionary perspective, quite sensible. In other words, this particular social-perceptual bias may well have had the capacity to increase the probabilities of both survival and reproduction for our ancestors.

Examples of Murphy's Law in Everyday Life

Largely attributed to U.S. aerospace scientist Edward Murphy (whose work was conducted predominantly in the 1940s), Murphy's Law is a somewhat satirical and pessimistic sentiment at its core: Whatever can go wrong will go wrong (see Matthews, 1997). It is interesting that this concept was borne of the field of aerospace engineering, as this is a field where small errors may lead to major catastrophes. If you're an aerospace engineer, in other words, you better make sure that you know you're making the right decisions. Mistakes are not particularly welcomed in this field.

Since the 1940s, this concept has been expanded well beyond the aerospace industry. Murphy's Law, essentially, applies to pretty much everything. Here are some examples of Murphy's Law in everyday life:

  • If your buttered toast falls off your plate, it will certainly fall butter-side down.
  • If you think that you accidentally texted a questionable message to the incorrect person, you almost certainly did exactly that.
  • If you are late to a job interview and rushing along the sidewalk, there are likely multiple banana peels ahead of you on the path.
  • If you forget your laptop computer on a cross-country flight, you are pretty much guaranteed to run out of battery and lose all your data just before you land.

And so forth.

In terms of our lived experiences, it certainly often feels that things are just stacked against us. In a sense, we can think of this general issue as the negativity bias (see Rozin & Royzman, 2001) which permeates so much of our psychology. It certainly, quite often, feels that everything that could go wrong, even in terms of the most benign outcomes, does go wrong. Murphy's Law is often the stuff of memes. And we often find these memes funny because they are so relatable to so many of us.

An Evolutionary Perspective on Murphy's Law

In a powerful paper on social-cognitive biases, evolutionary psychologists Martie Haselton and Daniel Nettle (2006) discuss humans as paranoid optimists. This conception of common social psychological biases focuses partly on the idea that humans (even everyday "normal" humans) are often overly paranoid.

As we are 200 miles on our road trip across the country, we might find ourselves afraid that we have left the stove on. After we have sent an email to our full organizational community, we re-read it three times to make sure that we have said nothing that could possibly be construed as offensive. After we post a video on social media, we watch it—and re-watch it—multiple times, working to make absolutely certain that we have said nothing that makes no sense, makes us look bad, or might be taken the wrong way, etc.

According to Haselton and Nettle (2006), such a tendency toward pessimism could have all kinds of evolutionary benefits. Being pessimistic is, in their conception, akin to an overly sensitive smoke detector: That particular smoke detector is wrong most of the time. But darn—the benefits that follow from the smoke detector being right even once can truly be life-saving.

Such a pessimistic bias, as unpleasant as it may be, may well save our lives—increasing Darwin's bottom line: the capacity to survive and reproduce.

Bottom Line

Sure, a pessimistic bias may be quite unpleasant. It may cause us to drive 200 miles straight back home to check the stove. It may cause us to re-read a to-be-sent email 20 times. It may well lead us to check our face in the mirror a dozen times during a night out on the town (Is there spinach in my teeth?).

Such everyday paranoia can be seen as boiling down to a lay understanding of Murphy's Law. Often, in our everyday lives, we feel and act as if the worst-case scenario is nearly guaranteed. We act as if anything that can go wrong certainly will go wrong.

While this bias hardly matches the observable, empirical world in all cases (i.e., it's not really always the case that worst-case scenarios happen all the time), holding such a view may well help us put out the rare fires that actually do flare up on occasion in everyday life. And being overly vigilant about such outcomes may well have helped our ancestors to live another day.

Long live Murphy's Law!

(Now let's hope that this piece has no typos, as I have proofread it about 30 times...)


Haselton MG, Nettle D. The paranoid optimist: an integrative evolutionary model of cognitive biases. Pers Soc Psychol Rev. 2006;10(1):47-66. doi: 10.1207/s15327957pspr1001_3. PMID: 16430328.

Matthews, Robert A.J. (April 1997). "The Science of Murphy's Law". Scientific American. 276 (4): 88–91. Bibcode:1997SciAm.276d..88M. doi:10.1038/scientificamerican0497-88.

Rozin, P., & Royzman, E. B. (2001). Negativity Bias, Negativity Dominance, and Contagion. Personality and Social Psychology Review, 5(4), 296–320.

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