Complexity bias is a logical fallacy that leads us to give undue credence to complex concepts. Faced with two competing hypotheses, we are likely to choose the most complex one. As a result, when we need to solve a problem, we may ignore simple solutions — thinking “that will never work” — and instead favor complex ones.

We often find it easier to face a complex problem than a simple one.

A person who feels tired all the time might insist that their doctor check their iron levels while ignoring the fact that they are unambiguously sleep deprived, hyper-stressed or overworking.

Someone experiencing financial difficulties may stress over the technicalities of their telephone bill while ignoring the large sums of money they spend on slot machines.

Someone who is overweight is prone to look for some food intolerance, consulting numberless doctors and even some peudo-doctors and charlatans, rather than realizing that simply reducing the food intake would decrease his weight.

Marketers make frequent use of complexity bias.

They do this by incorporating complex technical language or insignificant details into product packaging. Technical-sounding terms can be particularly persuasive – they give an air of competence on the buyers. Sometimes they can make us believe a product is credible even when we don’t know what they mean.

For example ‘micro-peptides’ feature on some miracle face cream…..”probiotics” feature in some yoghurt….

Most of the people have no idea what micropeptides and probiotic mean! And even the scientist – yet they know the meaning of those words – have no idea of the impact of them the alleged and advertised benefit of the product.

We, human beings,  are pattern-seeking animals. It’s part of our DNA. That’s why conspiracy theories, Gods and Superstitions are so popular: humans end to to see things being more complex and bigger than they actually are.

Funnily enough, animal studies have revealed much the same tendency, In particular, consider B.F. Skinner’s well-known research on the effects of random rewards on pigeons. Skinner placed hungry pigeons in cages equipped with a random-food-delivery mechanism. Over time, the pigeons came to believe that their behavior affected the food delivery. Skinner described this as a form of superstition. One bird spun in counterclockwise circles. Another butted its head against a corner of the cage. Other birds swung or bobbed their heads in specific ways.

Skinner wrote (in “‘Superstition’ in the Pigeon,” Journal of Experimental Psychology, 38):

“The bird behaves as if there were a causal relation between its behavior and the presentation of food, although such a relation is lacking. There are many analogies in human behavior. Rituals for changing one’s fortune at cards are good examples. A few accidental connections between a ritual and favorable consequences suffice to set up and maintain the behavior in spite of many unreinforced instances. The bowler who has released a ball down the alley but continues to behave as if he were controlling it by twisting and turning his arm and shoulder is another case in point. These behaviors have, of course, no real effect upon one’s luck or upon a ball half way down an alley, just as in the present case the food would appear as often if the pigeon did nothing—or, more strictly speaking, did something else”

Humans, like pigeons, tend to see complexity where only randomness exists. The sense of losing control over the world around us increases the likelihood of our believing in conspiracy theories. Faced with natural disasters and political or economic instability, we are more likely to concoct elaborate explanations.

The assumption that someone knows what they are talking about because they use obscure terminology and big words.

The story I’m going to present you is highly suggestive of our awe towards complexity, even from “erudite” people.

The famous mathematician Euler was a believer in God, downright and straightforward. The following story is told by Thiebault, in his “Memoirs of Twenty Years of Residence in Berlin”, published in1804. This volume was fully received as trustworthy at the point that Marshall Mollendorff, the commander of Prussian Army, told the Duc de Bassano in 1807 that it was the most veracious of books written by the most honest of men.

Thiebault, in his book, says that he has no personal knowledge of following the truth of the story, but that it was believed throughout the whole of the north of Europe.

Diderot, the re-known french encyclopedist,  paid a visit to the Russian Court at the invitation of the Empress. He conversed very freely, and gave the younger members of the Court circle a good deal of lively atheism. The Empress was much amused, but some of her councillors suggested that it might be desirable to check these expositions of doctrine. The Empress did not like to put a direct muzzle on her guest’s tongue, so the following plot was contrived. Diderot was informed that a learned mathematician was in possession of an algebraical demonstration of the existence of God, and would give it him before all the Court, if he desired to hear it. Diderot gladly consented: though the name of the mathematician is not given, it was Euler.

The mathematician advanced towards Diderot, and said gravely, and in a tone of perfect conviction

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Diderot, to whom algebra was Hebrew, was embarrassed and disconcerted; while peals of laughter rose on all sides, he asked permission to return to France at once, which was granted.

This fallacy is typical in the field of investing or trading in stock market:  we would believe that our goals can only be achieved with the use of sophisticated portfolios or trading techniques, or that more complex is the trading-investing approach higher shall be the yield. Instead, as abundantly studied and tested by the most famous academicians and investors –  Malkiel, Swensen, Bogle, Buffet, Bernstein, Dalio – simple no-brainer portfolios, held passively, have been always the winners on long run.





– image 1972 ACM A.M. Turing Award winner Edsger W. Dijkstra. Credit: The University of Texas at Austin