Darwin goes to Wall Street

Since the financial crash of 2008 the field of economics has been in a state crisis, where a paradox lies at the heart of the issue.

On the one hand markets are remarkably rational and efficient, displaying allocation and foresight that prediction scientists are only beginning to fully grasp. Efficient markets are powerful, practical tools for aggregating information, and they do it more quickly and cheaply than any known alternative.

However markets also prone to wild swings of irrationality, and can fail spectacularly. Indeed, soul searching in the wake of the financial crisis has led to calls for the field of economics to be revolutionised. Behavioural economics has since risen in prominence, challenging the orthodoxy of neoclassical economic theory by outlining how predictably irrational people can be.

What can we make of this apparent contradiction?

In Adaptive Markets, MIT finance professor Andrew Lo ambitiously calls for a paradigm shift in financial economics, and urges us to reconsider financial markets from an evolutionary perspective. Lo argues by understanding the evolutionary forces that have shaped human behaviour and spurred financial innovation we can reconcile these paradoxical findings, and successfully address the problems facing the financial world.

It Takes a Theory to Beat a Theory

One passage from the book that stuck with me is where Andrew tells the story of taking his son to the National Zoo in Washington DC, who was then a toddler. “As expected, my son was delighted with the Great Ape House, but for me, this visit was nothing less than transformational.”

Lo describes his family standing in front of a group of orangutans, where the alpha male of the group came surprisingly close to the iron-bar fencing separating the great apes from the visitors. In response, Andrew pulled his son away from the fence to keep him out of danger. This startled the alpha male’s companion, who instantly moved in front of the younger orangutan to repel Andrew’s advance- in essence mirroring each other’s behaviour.

The human brain works in mysterious ways. At that precise moment, I saw clearly how the Efficient Markets Hypothesis and its behavioural critique could be reconciled. In fact I understood two things that should have been obvious to me all along, but which I had never thought about until then.

The first insight Andrew had was just how instinctive our primate behaviour is and the the legacy of our shared ancestry, where 97% of our DNA is identical to that of chimpanzees. However Andrew notes the large gulf between our species, where one of these primates carried on their life as usual held in captivity, where the other would go on to write a book detailing the experience and resolving a longstanding academic controversy. Lo argues it is this 3% of the human genome that separates us from other primates, which enables cultural innovation and human ingenuity, and permits advanced economic activity and efficient trading.

The core argument presented in Adaptive Markets is that financial markets do not follow the laws of economic theory. Rather, financial markets are the product of human evolution, and follow the laws of biology instead.

Undoubtedly, behavioural economists have helped improve our understanding of economic decision-making. However, what behavioural economists neglected to answer is the ultimate question: why do people possess these psychological dispositions? Answering ultimate questions leads one to evolution, as the human brain has been honed by the forces of natural selection.

As stated by Lo:

Economic behavior is one aspect of human behavior, and human behavior is the product of biological evolution across eons of different environments. Competition, mutation, innovation, and especially natural selection are the building blocks of evolution. All individuals are vying for survival- even if the laws of the jungle are less vicious on the African Savannah than on Wall Street. It’s no surprise, then, that economic behavior is often best viewed through the lens of biology.

A key concept Lo uses to explain economic behaviour is an evolutionary mismatch:  traits selected for in our ancestral past which were once advantageous, which become maladaptive when the environment changes. For example, Lo argues evolution can help explain loss aversion and people’s inclination to ‘probability match’ in financial settings, which can result in sub-optimal investing.

Financial behavior that may seem irrational now is really behavior that hasn’t had sufficient time to adapt to modern contexts. An obvious example from nature is the great white shark, a near- perfect predator that moves through the water with fearsome grace and efficiency, thanks to 400 million years of adaptation. But take that shark out of the water and drop it onto a sandy beach, and its flailing undulations will look silly and irrational. It’s perfectly adapted to the depths of the ocean, not to dry land.

For the past 50 years, academic finance has been dominated by highly mathematical models and methods that derived from physics. These sophisticated quantitative techniques spawned a wave of financial innovation, and triggered an evolutionary change within the world of finance. However, Lo argues that despite the advantages these advanced quantitative techniques provided, this mass ‘mathematization’ of finance has significant flaws.

Finance isn’t physics, despite the similarities between the physics of heat conduction and the mathematics of derivative securities, for example. The difference is human behavior and the role of evolution in its development… The financial crisis showed us that investors, portfolio managers, and regulators do have feelings, even if those feelings were mostly disappointment and regret during the last few years. Financial economics is much harder than physics.

The Financial Crisis

Much of Adaptive Markets is dedicated to the 2008 financial crisis. Although there are numerous causes of the crisis, Lo argues that at the most fundamental level the primary cause of the crash was greed overpowering fear.

The Adaptive Markets Hypothesis tells us that, at the most basic level of the financial crisis, greed overwhelmed fear. Ignoring the changing environment, people at all levels of the system created a narrative that greed was good. The pushback against the warnings about the oncoming crisis was stronger than the warnings themselves- until it was too late. 

Rather soberingly, Lo details how economists such and Robert Shiller and Raghuram Rajan raised the alarm of the American housing market showing signs of a bubble, which could potentially lead to a catastrophic meltdown of the financial system. However, these concerns were largely ignored by the wider financial community. With the benefit of hindsight, such warnings were remarkably prescient.

Lo’s own research on the hedge fund industry also showed early warning signs of the financial crisis. Back in 2005, journalist Mark Gimein published an overview of Lo’s research in the New York Times. The last paragraph reads; “The nightmare script for Mr. Lo wold be a series of collapses of highly leveraged hedge funds that bring down major banks or brokerage firms that lend to them”.

Apparently Lo’s warning seemed ridiculous at the time, yet in hindsight various hedge funds collapsed at the start of the crisis “and the fact that Bear Stearns and Lehman Brothers both experienced their first wave of losses through their hedge funds, it wasn’t too far off the mark.”

Hedge funds are described by Lo as the ‘Galapagos Islands of finance’, being a novel species of finance that exploit market anomolies which are highly vulnerable to changing environments. According to Lo, increased complexity combined with tighter coupling and a new spawn of financial gigantism increased the odds of a catastrophic meltdown.

Lo also takes the opportunity to challenge the narratives we share to explain the financial crisis. For example, one common theme is that the financial crisis was the result of the unscrupulous practices of financial elites. Although there is much truth to this story, Lo argues many determinants of the crisis were systemic and were not caused by ethical lapses. However, this claim is contested by leaders in the field.

Finance Behaving Badly

Not only does Adaptive Markets cover the basics of evolutionary psychology, it also makes reference to the cultural evolution. Lo makes clear that culture, a domain which is frequently deemed beyond the realm of biology, is itself the product of evolution. That is, subject to the processes of variation, selection and replication. A core argument in Adaptive Markets is that an evolutionary perspective of culture can help us identity and prevent financial scandals.

Long before the days Gordon Gekko became a cultural icon, social psychologists have studied what leads ordinary people to behave like monsters. The infamous Milgram and Zimbardo Stanford prison experiments were conducted during the 1960s and 1970s respectively, and demonstrated in shocking and graphic detail how blind obedience to authority can lead ordinary people to commit atrocities.

Lo notes how little people were paid to participate in these experiments, and yet still were complicit in such unthinkable acts. Milgram paid his participants roughly today’s equivalent of $36, where Zimbardo paid his subjects roughly $90 in today’s money.

Imagine a situation in which you were instructed to engage in questionable financial practices- actions that aren’t nearly as gut-wrenching as delivering electrical shocks- by a managing director or vice president in a suit and tie, and you’re given tremendous financial incentives, like a multi-million dollar year-end bonus, to do so. In light of the Lucifer Effect, it’s not hard to understand how context and culture can lead to even caring and ethical individuals to do reprehensible things to unsuspecting clients. This is the Gekko Effect. 

One possible critique of Adaptive Markets is that it emphases the importance of the environment, yet it does not adequately address the environmental forces shaping financial institutions. However, Lo’s reflections on regulation and corporate fraud is a clear exception.

Although the data is confined to the United States and the time series is rather small (especially when considering evolutionary time-scales), Lo provides evidence that financial scandals and scams are cyclical. That is, historically financial scandals have increased as stock markets rose, and declined once market conditions deteriorated.


Lo Dyck, Morse and Zingale's (2013, figure 1) estimates of the percentage of large corporations starting and engaging in fraud

Estimates of the percentage of large corporations starting or engaging in fraud, from 1996-2004 (Dyck, Mores & Zingales, 2013)

Deason et al (2015) Frequency of SEC- prosecuted Ponzi schemes by calendar quarter from 1988 to 2012

Frequency of SEC prosecuted Ponzi schemes by calendar quarter from 1988 to 2012 (Deason, Rajgopal & Waymire, 2015)

These findings may seem counter-intuitive. However, the researchers investigating ponzi schemes make it clear that such large-scale fraud is harder to sustain during deteriorating market conditions, as was the case with Madoff. Lo also notes that regulatory budgets increase after financial bubbles burst.

Lo states the unravelling of Madoff also revealed the biases and blind spots of financial regulators. Although social scientists have much to learn about the behaviour of auditors and financial regulators in the lead up to such scandals, Lo argues loss aversion may help explain why regulators don’t react quicker to signs of disturbance. That is, being more concerned about being wrong and causing a public scandal than investigating cases of potential large-scale fraud.

Fixing Finance 

Lo argues that if we wish to change financial culture and tackle corporate malfeasance, we first have to understand the broader contextual and environmental forces that have shaped such cultures over time and across circumstances.

As a professional working in the field, I’ve observed increasing activity to monitor aspects of organisational culture within the banking industry. However, I believe we’re only beginning to grapple with this challenge, and that various issues need to be addressed. To elaborate, what do we mean exactly when we refer to ‘culture’, how do we measure it, and which aspects of culture can actually be changed and should be prioritised?

Lo provides some excellent advise here, and demonstrates the importance of framing.

The first step requires a subtle but important shift in our language. Instead of seeking to “change culture”, which seems naive and hopelessly ambitious, suppose our objective is to engage in “behavioural risk management” instead… Despite the fact we’re referring to essentially the same goal, the latter phrase is more concrete, feasible, and- this is important- unassailable from a corporate board’s perspective.

To conclude, a core theme of Adaptive Markets is that the financial system is more similar to an ecosystem of living organisms than a machine, and that we must manage the system accordingly. This is a very different perspective compared to traditional approaches of financial regulation, however Lo notes the list of prominent economists who have reached similar conclusions.

Despite certain reviews of the book arguing that the Adaptive Markets Hypothesis offers little practical value, this theoretical insight arguably has many practical implications.

For one, it shows investors how markets are not wholly efficient and can be beaten, and makes clear that specific investment strategies can either succeed or fail depending on the broader financial environment.

Lo shares some big ideas on how large-scale investment funds can be designed to address pressing social problems, such as the high cost of developing new cancer drugs.

For regulators, the adaptive toolkit provides ways of addressing the cultural roots of corporate maleficence, which could help prevent the next Bernie Madoff from succeeding.

Written by Max Beilby for Darwinian Business

Click here to buy a copy of Adaptive Markets

Why anti-corruption strategies may backfire

One of the defining attributes of humans is that we are champion cooperators, surpassing levels of cooperation far beyond what is observed in other species across the animal kingdom. Understanding how cooperation is sustained, particularly in anonymous large-scale societies, remains a central question for both evolutionary scientists and policy makers.

Social scientists frequently use behavioural game theory to model cooperation in laboratory settings. These experiments suggest that ‘institutional punishment’ can be used to sustain cooperation in large groups- a set up analogous to the role governments play in wider society. In the real-world however, corruption can undermine the effectiveness of such institutions.

In July’s edition of the journal Nature Human Behaviour, Michael Muthukrishna and his colleagues Patrick Francois, Shayan Pourahmadi and Joe Henrich published an experimental study which rather cleverly incorporated corruption into a classic behavioural economic game.

Corruption worldwide remains widespread, unevenly distributed and costly. The authors cite estimates from the World Bank, stating US$1 trillion is paid in bribes alone each year. However, levels of corruption vary considerably across geographies. For example, estimates suggest that in Kenya 8 out of 10 interactions with public officials require a bribe. Conversely, indices suggest Denmark has the lowest level of corruption, and the average Dane may never pay a bribe in their lifetime.

Transparency International state that more than 6 billion people live in countries with a serious corruption problem. The costs of corruption range from reduced welfare programmes, to death from collapsed buildings. In other words, corruption can kill.

Michael Muthukrishna’s work suggests that corruption is largely inevitable due to our evolved psychological dispositions; the challenge is apparently to find the conditions where corruption and its detrimental impacts can be minimised. As Muthukrishna is quoted saying in an LSE press release for the paper:

Corruption is actually a form of cooperation rooted in our history, and easier to explain than a functioning, modern state. Modern states represent an unprecedented scale of cooperation that is always under threat by smaller scales of cooperation. What we call ‘corruption’ is a smaller scale of cooperation undermining a larger-scale.

Playing Bribes

What follows is an overview of the studies’ experimental design and results. If this is of little interest, I suggest skipping to the section titled ‘Backfire effect’.

To model corruption, the authors modified a behavioural economic game called the ‘institutional punishment game’. The participants were anonymous, and came from countries with varying levels of corruption. Overall, 274 participants took part in the study. The participants were provided with an endowment, which they could divide between themselves and a public pool. The public pool is multiplied by some amount and then divided equally among the players, regardless of their contributions.

The institutional punishment game is designed so that it is in every player’s self-interest to let others contribute to the public goods pool, whilst contributing nothing oneself. However, the gain for the group overall is highest if everybody contributes the maximum possible. Each round one group member is randomly assigned the leader, who can allocate punishments using taxes extracted from other players.

The ‘bribery game’ that Muthukrishna and his colleagues developed is the same as the basic game, except that each player had the ability to bribe the leader. Therefore, the leader could see both each players’ contributions to the public pool, and also the amount each player gave to them personally. The experimenters manipulated the ‘pool multiplier’ (a proxy for economic potential) and the ‘punishment multiplier’ (the power of the leader to punish).

For each player’s move, the leader could decide to do nothing, accept the bribe offered, or punish the player by taking away their points. Any points offered to the leader that he or she rejected were returned to the group member who made the offer. Group members could see only the leader’s actions towards them and their payoff, but not the leader’s actions towards other group members.

Compared to with the basic public goods game, the addition of bribes caused a large decrease in public good provisioning (a decline of 25%).

Leaders with a stronger punishment multiplier at their disposal (referred to as ‘strong leaders’) were approximately twice as likely to accept bribes and were three times less likely to do nothing (such as punish free-riders). As expected by the authors, more power led to more corrupt behaviour.

Having generated corruption, the authors introduced transparency to the bribery game. In the ‘partial transparency’ condition, group members could see not only the leader’s actions towards them, but also the leader’s own contributions to the public pool. However, they did not see the leader’s actions to other group members. In the ‘full transparency’ condition, information on each member and the leader’s subsequent actions was made fully available (that is, individual group members contributions to the pool, bribes offered to the leader, and the leader’s subsequent actions in each case).

Although the costs of bribery were seen in all contexts, the detrimental effects were most pronounced in the poor economic conditions.

The experiments demonstrated that corruption mitigation effectively increased contributions when leaders were strong or the economic potential was rich. When leaders were weak (that is, their punitive powers were low and economic potential was poor), the apparent corruption mitigation strategy of full transparency had no effect, and partial transparency actually further decreased contributions to levels lower than that of the standard bribery game.

Backfire effect

The study indicates that corruption mitigation strategies help in some contexts, but elsewhere may cause the situation to deteriorate and can therefore backfire. As stated by the authors; “[…] proposed panaceas, such as transparency, may actually be harmful in some contexts.”

The findings are not surprising from a social psychological perspective, and support a vast literature on the impacts of social norms on behaviour. Transparency and exposure to institutional corruption may enforce the norm that most people are engaging in corrupt behaviours, and that such behaviour is permissible (or that one needs to also engage in such dealings to succeed). Why partial transparency had a more detrimental impact than full transparency when leaders were weak is not made clear however.

Remarkably, the authors found that participants who had grown up in more corrupt countries were more willing to accept bribes. The most plausible explanation presented is that exposure to corruption whilst growing up led to these social norms being internalized, which manifested in these individuals’ behaviour during the experiments.

It’s important to note that this is only one experimental study looking into anti-corruption strategies, and that caution is required when extending these research findings to practice. As stated by the authors; “Laboratory work on the causes and cures of corruption must inform and be informed by real-world investigations of corruption from around the globe.”

This aside, the authors’ research challenges widely held assumptions about how best to reduce corruption, and may help explain why the ‘cures for corruption’ which may prove successful in rich nations may not work elsewhere. To paraphrase the late Louis Brandeis, ‘sunlight is said to be the best of disinfectants, yet this may depend on climatic conditions and the prevalence of pathogens’.

Written by Max Beilby for Darwinian Business

Click here to read to full paper.



Muthukrishna, M., Francois, P., Pourahmadi, S., & Henrich, J. (2017). Corrupting cooperation and how anti-corruption strategies may backfire. Nature Human Behaviour.

Milinski, M. (2017). Economics: Corruption made visible. Nature Human Behaviour.

When Less is Best (LSE, 2017); Available here

Corruption Perceptions Index 2015 (Transparency International, 2015); Available here 


Image credit: George Marks/Getty Images.


Why attractive people earn more money

A little discussed aspect of pay discrimination concerns physical attractiveness.

Physically attractive individuals are more likely to be interviewed and secure job offers, they are more likely to advance rapidly in their careers, and they earn higher wages than less attractive individuals.

Recently published in the journal Behavioral & Brain Sciences, behavioural biologist Dario Maestripieri and his colleagues Nora Nickels and Andrea Henry at the University of Chicago have written a paper explaining why the ‘beauty premium’ exists.

Previous explanations

The authors argue that these biases have “baffled economists for decades because they are not predicted by their rational models of human behavior.” According to the taste-based discrimination model developed by economists, attractiveness-related financial and prosocial biases are the product of individual preferences or prejudices.

This explanation is unsatisfactory for various reasons. Taste-based discrimination does not differentiate domains, and it does not explain why people have these preferences in the first place. Because empirical support for economists’ explanations is weak, the authors contend economists have frequently avoided explanations for this phenomenon altogether.

Social psychologists have also tried to explain these biases. According the authors, social psychologists  have maintained that attractiveness is seen as a marker of positive traits, such as a favourable personality, trustworthiness, and professional competence.

Maestripieri and his colleagues review studies looking into the favourable treatment of attractive individuals, and find no evidence for this explanation.

Firstly, it is ruled out that physical attractiveness accompanies these qualities. For example, studies on the jobs market which included information about people’s personality traits found that attractive employees earned higher wages, even after controlling for personality.

Although the jury is still out, laboratory based experiments suggest that attractive people may actually be less cooperative and less trustworthy than others. The authors argue that this is most likely due to attractive individuals expecting favourable treatment, and are therefore less inclined to cooperate.

Cited in the paper is a meta-analysis on the effects of attractiveness on hiring decisions, which concluded biases in favour of attractive people are independent of the amount of job-relevant information employers have about potential employees. If positive stereotypes were the cause, then the effect should be stronger when less information is available about potential employees.

Similarly, another meta-analysis cited found that preferential treatment is independent of familiarity: the effects of physical attractiveness are just as strong when people know each other as when they do not. If positive stereotypes were the cause, then one would expect favourable biases to recede once employers know their employees better.

Another dynamic which negates the positive stereotypes explanation is that when those doing the recruiting are women, attractive female job candidates are less likely to be hired than unattractive ones. Although less pronounced, there is some evidence that this also happens with men. If positive stereotypes were the cause, then attractive individuals would receive favourable treatment regardless of the recruiter’s sex.

Mating Motives

So what does explain these biases in favour of attractive employees?

According to Maestripieri and his colleagues, the best explanation is that attractive people are favoured because they are considered potential romantic partners. “Evolutionary psychologists… recognize that physical attractiveness has intrinsic value and it is not simply a marker of behavior. Therefore, there is an incentive to invest in attractive people because of their high mate value, regardless of their psychological or behavioral characteristics.”

An important caveat added by the authors is that these motivations can be activated without one’s conscious awareness, regardless of one’s moral principles, and irrespective whether such motivations would ever be acted upon. “[…] [T]he human mind is probably predisposed to respond to cues of mating and activate courtship behaviors regardless of any conscious awareness of goals, incentives, or probabilities of future gains.”

The evolutionary explanation also answers why attractive individuals receive less favourable treatment from members of the same sex during the hiring process. The authors argue this is the result of same-sex competition, manifesting in emotions such as jealousy and envy.

Likewise, evolutionary psychology can also explain why attractive women receive less favourable treatment from other women during the hiring process, whilst men are less susceptible to this. A robust sex difference concerning romantic interest is that men place more importance on physical beauty, whereas woman place greater emphasis on social status. Comparatively, attractive women are considered greater rivals than attractive men are.

The greatest evidence in favour of the evolutionary explanation comes from experiments involving attractive individuals as bystanders. If stereotype based theories were correct, then third-party observers are irrelevant and would therefore not impact subsequent behaviour. However, experiments have found that in the presence of attractive women, men behave more pro-socially in economic games; that men more frequently help strangers in need, and are more willing to make physical sacrifices for their group.

The evolutionary explanations of these favourable biases assume that multiple motivations may simultaneously be at play; some of these are related to obtaining resources (e.g. money), whereas others may be social (e.g. gaining status) or purely sexual. “Just as financial considerations can drive decisions about partner selection for romantic and mating purposes, it should not be surprising that mating motives can influence economic decision making”. The authors emphasise that sexual and financial motives are closely intertwined in human affairs.

A large body of research demonstrates that women are more selective than men in their choice of sexual partners, and of the circumstances in which sexual interactions can take place. Therefore, Maestripieri and his colleagues argue the effects of attractiveness on decision making may be more consistent, and perhaps stronger, in men than in women.

Homosexuality is not addressed within the paper. However, research suggests that gay men similarly place greater importance on physical appearance than women do (heterosexual or otherwise).


Unfortunately, the authors do not comment on how such biases could be addressed in practice.

Such biases may seem insurmountable. The authors note that men more frequently hold positions of power, including responsibility surrounding hiring decisions. Therefore, these biases may be amplified by the amount of men at the top of the hierarchy.

However, organisations could provide some safeguards throughout the hiring process. For a start, recruiters could require applicants’ names and gender to be removed from job applications, which would help remove such biases from the initial stages of the recruitment process.

A wealth of research demonstrates that cognitive debiasing techniques don’t work. However, this doesn’t mean bias cannot be addressed more successfully within groups. We may not be able to see the flaws in own thinking, however we can spot it more readily in others.

One approach organisations may want to explore are protocols for job interviews. For example, ensuring interview panels comprise a combination of men and women. Such a dynamic may help counter such biases when it comes to making hiring decisions.

Written by Max Beilby for Darwinian Business

Clive here to read the full paper

*Post updated 16th May 2017

Maestripieri, D., Henry, A., & Nickels, N. (2017). Explaining financial and prosocial biases in favor of attractive people: Interdisciplinary perspectives from economics, social psychology, and evolutionary psychology. Behavioral and Brain Sciences, 40.

Image credit: Selina Voilé

References & recommended reading

Buss, D. (2016) Evolution of Desire: Strategies of human mating (Revised Edition). Basic Books

Hamermesh, D. S. (2013) Beauty Pays: Why attractive people are more successful. Princeton University Press

Hosoda, M., Stone-Romero, E. F. & Coats, G. (2003) The effects of physical attractiveness on job-related outcomes: A meta-analysis of experimental studies. Personnel Psychology 

Langlois, J. H., Kalakanis, L., Rubenstein, A. J., Larson, A., Hallam, M. & Smoot, M. (2000) Maxims or myths of beauty? A meta-analytic and theoretical review. Psychological Bulletin, 126(3):390–423.