The origin of human behaviors and inventions has received far less attention than the origin of species, but their evolution too is central to contemporary science. Applied to human actions and devices, the frequently bandied about notions of insight, creativity, and genius have never gained a firm scientific foothold because these ideas are ill-defined.

Putting aside any subjective judgment about what’s creative or not, another account helps to explain the origin of our behaviors. The Law of Effect was discovered and named by Edward Thorndike 40 years after Charles Darwin published The Origin of Species. This simple, but powerful law holds that organisms tend to repeat the successful behaviors they perform and to refrain from repeating the unsuccessful ones. Just like the Law of Natural Selection, the Law of Effect involves an entirely mechanical process of variation-and-selection; further, it too blindly proceeds with no goal or end in sight to produce highly adapted behaviors from failure, not from function—a purely trial-and-error process.

Just how does the Law of Effect operate to produce adaptive behaviors and contrivances? Four different examples nicely illustrate the process.

The violin is a musical instrument with a mysterious origins story.[1] In a critical piece of that story, we have recently learned from scientific study[2] that its twin sound holes very slowly evolved over several centuries: from simple circular openings to curvaceous f-holes typical of the famous Cremonese violins of the Baroque period. That evolution had an important and quantifiable effect; it produced an increase in acoustic power, which was correlated with an increase in the size of concert halls, where more powerful instruments could accommodate ever larger audiences.

This change in sound-hole geometry did not occur suddenly, as one might have expected if it had sprung from an innovative, preconceived change in design. Instead, meticulous physical measurements of 470 violins made by three families—the Amati, the Stradivari, and the Guarneri—from 1550 to 1750 in the northern Italian city of Cremona that specialized in violin production, indicate that this evolution most likely involved a trial-and-error process. Small, random variations were made in one instrument and then passed down to another, where the violin makers could not have foreseen the instrument’s final construction decades or even centuries later. In other words, variation (from small disparities in craftsmanship) and selection (from small disparities in acoustic power) produced today’s violin—a case of survival of the fittest fiddle!

Moving to a second example within the realm of music, we might consider how lyricists go about putting words to music. A recent song illustrates how variation and selection operate.[3] Pulitzer prize-winning composer David Lang wrote Simple Song #3 for the film, Youth. This song has received considerable critical acclaim and was nominated for Best Original Song by the Academy Awards, the Critics’ Choice Awards, and the Golden Globe Awards. Unlike most songs, whose provenance is unknown, we know a good deal about the origin of this song’s lyrics.

Because of its intense intimacy and emotionality, Lang sought lyrics that might be whispered to one’s lover. To do so, he deployed an unorthodox method. “I just typed in a Google search …, ‘when you whisper my name I … ,’” he said. “I got thousands of pornographic things and terrible things and things that were so specific I couldn’t really use them. But I got a general catalog of what people say to their loved ones that they don’t want anyone else to hear.” From these variants, Lang chose a few and put them into a text to align with the melody. In this way, Lang composed a highly original and much heralded song without any inkling whatsoever of what its final lyrics would be. Indeed, others generated them (variation); he only chose them (selection).

A third example comes from the world of the theater.[4] In 2001, Mike Nichols was directing Philip Seymour Hoffman in Anton Chekhov’s famous play The Seagull. However, rehearsals were not going at all well. Nichols was finding Hoffman’s acting methods extremely frustrating. “Phil searches for his performances, and like all great actors how he does it is completely mysterious to me.” In his role as Konstantin, Hoffman was being the very model of inconsistency. “One day he was very loud, one day I couldn’t hear him, one day he wasn’t doing the right blocking [by moving to incorrect stage locations],” Nichols recalled. “I asked what was going on, and Phil said, ‘I have to do all the things I’m not going to ultimately do.’” He did finally refrain from repeating these inapt actions and settled on a set performance—variation-and-selection once again at work with no end in mind.

A final illustration of the Law of Effect comes from performance art.[5] Basil Twist is a 2015 MacArthur ‘genius’ award winner. The puppeteer’s breakthrough performance was a unique dynamic display set to Hector Berlioz’s hallucinatory Symphonie Fantastique. It was a puppet performance that didn’t involve puppets! It involved bubbles, feathers, garbage bags, ribbons, fringes, sparkles, and stenciled designs. Most importantly, its fantastical goings on took place in a giant tank of water! Was this innovative performance devised by Twist’s foresightful planning? Absolutely not!

While on a walk, Twist happened to spot a cracked fish tank in a recycling pile. He took it home, repaired it, filled it with water, and began a series of extemporaneous experiments. He first put a piece of silk on a coat hanger and dragged it through the water. The results encouraged him to buy a much larger tank and various other materials and to set the kinetic festivities to music. After trying different pieces of music, Twist settled on the famous Berlioz work. From a broken fish tank to an innovative pièce de résistance, we again witness variation and selection in action with no end in sight.

Is the selectionist approach to human behavior and invention I have been advocating of broad generality? How similar are the processes of variation and selection in the evolution of species to those involved in the evolution of behavior and its products? Is there no role at all for insight, creativity, and genius? It is still too soon to hazard firm answers to these profound questions. However, it is not too soon to explore them with the best empirical methods that behavioral science and neuroscience have at their disposal.

Orthodoxy holds that the things we make and do must have emerged by premeditation—by design. To that claim, we might ultimately have to reply: “Bye design!”


[1] Wasserman, E. A., & Cullen, P. (2016). Evolution of the violin: The Law of Effect in action. Journal of Experimental Psychology: Animal Learning and Cognition, 42, 116-122. http://dx.doi.org/10.1037/xan0000086.

[2] Nia, H. T., Jain, A. D., Liu, Y., Alam, M.-R., Barnas, R., & Makris, N. C. (2015). The evolution of air resonance power efficiency in the violin and its ancestors. Proceedings of the Royal Society of London. Series A, 471, 20140905. http://dx.doi.org/10.1098/rspa.2014.0905.

[3] Meyer, R. How to write a Golden Globe-nominated song with Google. The Atlantic, January, 9, 2016.

[4] Healy, P. Searching for the Life of a Salesman. The New York Times, March 8, 2012.

[5] Acocella, J. Puppet love. The New Yorker, April 15, 2013.

Published On: July 8, 2016

Ed Wasserman

Ed Wasserman

Ed Wasserman is the Stuit Professor of Experimental Psychology in the Department of Psychological and Brain Sciences at The University of Iowa. He is a founding member and Past President of the Comparative Cognition Society and co-editor of the Oxford Handbook of Comparative Cognition. His research experimentally explores learning, memory, and cognition in humans and nonhuman animals.

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