Herd Behavior

It’s a familiar scene in a nature documentary. Thousands of wildebeests are fleeing together from the pursuit of a lion. Aerial footage follows the wildebeests moving together, leaving a trail of dust preceded by the thundering of countless hooves. It’s an epic image, and we marvel in the scope of the herd acting as a single unit. We might think how different we are, as individualized human beings, acting on our own accord. But with a closer look, we may realize that we are more like the wildebeests than we first believe.

It’s no secret that humans are social creatures. Our motives in presenting an idealized social identity to our peers guide much of our behavior, and although some of these social influences can result in our attempt to project individuality (at least in North America), there are some situations where we do the opposite – we follow the herd; our heads go down and we do what everyone else is doing.

Herding: As outlined by a group of psychologists from University College London:¹ “Herding can be broadly defined as the alignment of thoughts or behaviours of individuals in a group (herd) through local interactions rather than centralized coordination.”

Ideas related to herd behavior have been around for many years. They have received attention from notable 19th-century Western philosophers who derided the herd as the antithesis of individuality. Søren Kierkegaard, the famous Danish philosopher, celebrated the individual over “the crowd,” while similar ideas also derived great attention from Friedrich Nietzsche,² who once remarked that, “the concept of greatness entails being noble, wanting to be by oneself, being able to be different, standing alone and having to live independently.”

The foundation of these notions likely go back much earlier than Kierkegaard and Nietzsche, to ancient musings on the nature of the individual, and are consistent with the intellectual ideals in the West that champion individuality. Aside from philosophy, interest in group behavior in psychology can also be found in the 19th century. In 1895, Gustave Le Bon, a French polymath, published The Crowd: A Study of the Popular Mind which focused on the crowds on the French Revolution. Le Bon’s text would influence Sigmund Freud’s own theories on crowd psychology,³ as well as the works of Wilfred Trotter, who in 1914 published Instincts of the Herd in Peace and War, which became a classic in the realm of social psychology and has been credited with popularizing the term “herd behavior.”

As the field of psychology evolved, so did evidence and support for conforming to certain behaviors. While the Freudian approach to psychology went out of fashion, experimental studies filled the void in psychological inquiry. One of these studies came from Solomon Asch in 1951, illustrating the effects of conformity on human decision-making,4 and continues to be taught in introductory psychology courses across the world. In the experiment, Asch had groups of eight participants assess the length of three lines in relation to a target line. One of the lines was identical to the target line, while the other two were unambiguously longer or shorter. Of the groups of eight participants, however, seven were in on the experiment. Asch had them pretend to think that one of the longer or shorter lines was the same length as the target. The purpose of the study was to determine whether the “real” participants would change their correct answer to conform to the group’s incorrect answer. Incredibly, roughly 37% of responses conformed to the incorrect group response, despite the error rate being less than 1% when people were asked to assess the lines on their own.

Asch’s finding is quite remarkable when you look at the lines and see just how obvious the correct answer is. The error in the result is apparent, and it highlights the irrationality of group decision-making. This fallibility in conformity has given rise to familiar concepts such as groupthink and the bandwagon effect; such attention to these real-world behaviors that lead to erroneous decisions has made the concept of herding ripe for the field of behavioral economics, which was largely built upon efforts to empirically support evidence of human irrationality. The interest in herding behavior within behavioral economics has resulted in considerable research on herding within financial markets and has created a strong conceptual link between herding and economic decision-making.

As previously mentioned, herd behavior has received considerable attention in the realm of financial markets. Group-level irrationality in the form of herding can lead to market inefficiencies such as stock market bubbles.⁵ Consider the 2008 global financial crisis, where one can easily imagine a number of investors avoiding making an independent decision based on available information, and instead opting to do what everyone else is doing: buying mortgage-backed securities. Cryptocurrencies such as bitcoin are another example of a speculative bubble where herding has been suggested as partially responsible for the early exponential rise in value that preceded the large sell-off in 2018.6

While the term “herd behavior” in the academic literature predominantly applies to financial markets, if we consider the definition of herding outlined earlier, it’s easy to imagine a significant role of herd behavior in the formation of political opinion. The notion of thoughts and behaviors stemming from local interaction rather than centralized coordination can arguably explain a large portion of activity on social media. The same authors from University College London whose definition of herding1 can be found in the key terms section of this article also wrote: “One wonders, in this internet age with the increasing ease of sharing information and ideas, and with ever proliferating points of contact between people, whether we will be more susceptible to herding.” It is important to note that their paper was published in 2009, just two years after the first iPhone was released. Given the growth in the presence of technology and social media since 2009, one doesn’t have to question whether the internet age will make us more susceptible to herding. It might be clear to many that an aspect of herd behavior in belief formation is manifesting in online echo chambers that occur through social media channels and search engines.7

Few would argue that people never follow others’ behavior over making an independent decision, so herd behavior as a concept is rarely challenged. Any criticisms over the matter are more likely to arise over particular studies or interpretations of certain effects. For example, Asch’s famous conformity study from 1951 has been criticized by some for lacking ecological validity, meaning the finding isn’t very applicable to the real world. Others have voiced criticisms of the study such as the rather homogenous sample of young male participants, issues around the test stimuli, or that the result was more of an artifact of American culture in the 1950s.⁸ These criticisms are part of sound science that attempts to challenge conventional beliefs and classic studies. Whether or not the criticisms are true, however, is up for debate. But regardless of the concerns highlighted, the notion of herd behavior does not solely rest on Asch’s study.

Online Book Sales

A study by Yi-Fen Chen of Christian University in Taiwan suggests a herding effect in online book sales.⁹ Chen offered experimental evidence that supports the claim that socially informative influences such as ratings and sales volume influence consumer decision-making. For anyone who has bought a book because it’s a New York Times Bestseller, the prospect of buying something because others have done so might be relatable.

A Run on Toilet Paper

During the first weeks of the COVID-19 pandemic, an unprecedented amount of people made their way to the store to try and purchase toilet paper. In Canada for example, toilet paper sales increased by roughly 250% in March of 2020¹⁰, which led to many stores running out of stock. Experts have proposed a number of theories as to why the stockpiling was so acute for toilet paper. One potential explanation is herd behavior. Once people hear that others are buying up toilet paper, they decide to follow suit.

Group Decision Making: How to be Effective and Efficient

This piece highlights the perils of groupthink and how a herd mentality can hinder an organization, while offering a few principles in how to overcome such barriers.

Phantasy: The Unconscious Processes Behind Financial Instability

This piece includes a conversation between TDL and Selim Aren, a professor in business administration who discusses the role of herd behavior in financial bubbles.

1. Raafat, R. M., Chater, N., & Frith, C. (2009). Herding in humans. Trends in cognitive sciences, 13(10), 420-428.
2. Hargis, J. (2010). (Dis) embracing the herd: A look at Nietzsche’s shifting views of the people and the individual. History of Political Thought, 475-507.
3. Veness, H. (1971). The Psychology of Crowd Behaviour: A Review of Freud’s Theories in the Light of Contemporary Historical Research. Australian & New Zealand Journal of Psychiatry, 5(3), 199-205.
4. Asch, S. E., & Guetzkow, H. (1951). Effects of group pressure upon the modification and distortion of judgments. Organizational influence processes, 295-303.
5. Banerjee, A. V. (1992). A simple model of herd behavior. The quarterly journal of economics, 107(3), 797-817.
6. da Gama Silva, P. V. J., Klotzle, M. C., Pinto, A. C. F., & Gomes, L. L. (2019). Herding behavior and contagion in the cryptocurrency market. Journal of Behavioral and Experimental Finance, 22, 41-50.
7. Flaxman, S., Goel, S., & Rao, J. M. (2016). Filter bubbles, echo chambers, and online news consumption. Public opinion quarterly, 80(S1), 298-320.
8. Perrin, S., & Spencer, C. (1981). Independence or conformity in the Asch experiment as a reflection of cultural and situational factors. British Journal of Social Psychology, 20(3), 205-209.
9. Chen, Y. F. (2008). Herd behavior in purchasing books online. Computers in Human Behavior, 24(5), 1977-1992.
10. Statistics Canada. (2020). Retrieved from https://www150.statcan.gc.ca/n1/en/pub/62f0014m/62f0014m2020004-eng.pdf?st=3fwaSPre