Our prehistoric brain in the laboratory: encouraging cooperation through identity-bias


Dr. Yvan Russell

Biologists define “social” and “cooperation” with a very wide ambit: “social” refers to organisms that clump together (e.g. individual cells in the human body) and “cooperation” is collective action that benefits the whole (e.g. cells in the human body “cooperate” to keep the person alive). Success at lower levels of organisation, however, does not guarantee success at higher levels. Think of a “successful” group of cancer cells that eventually kill their human host; or, a human team member whose excessive self-interest causes an organisation to falter.

When you observe a group of chimpanzees (as I did, during my PhD) what is really striking is how human-like they seem. They spend much of their time in quiet embrace, gently grooming each other, displaying a tenderness that appears to approximate human love. Other times, of course, they are utterly animalistic. They fight viciously, injure each other, draw blood, and otherwise display shocking cruelty. Clearly, the best and worst of human nature existed before we were human. Unlike other animals, however, humans benefit from language, culture, social institutions, and a bigger brain which allows us to construct societies that make routine cooperation possible on a large scale.

Most of the time, cooperation is habitual. We are embedded within familiar relationships, engaging in low-stakes cooperation. A working relationship with a colleague, for example, might be characterised by a routine willingness to help each other (without counting each and every reciprocation). At the small scale, we tend to do cooperation well. At larger scales, we don’t do quite as well. Looking globally, we have huge inequalities in the GDPs of countries, and highly inadequate cooperation between countries to ameliorate global poverty. The solution is to encourage cooperation with strangers.

Some scientists believe that our cognitive predisposition (that particularly human one which evolved in prehistoric hunter-gatherer societies) has made us proficient at cooperating in small groups, but ill-equips us to make the world a better place. If you look at social media (e.g. Twitter), you see that toxic tribalism seems rampant in our political discourse. Loves and hatreds are often crisply split along party political lines. Hate the leader of the political party you oppose. Love the leader of the political party you support. It’s an in-group/out-group mechanism run amuck. Prejudicial thinking is what makes such pernicious politics possible. In a sense, we can understand prejudice from a cognitive-time-resource-management point of view: it’s time-consuming (and often impossible) to get to know a stranger personally, but it’s quick and easy to categorise.

So, we’re stuck with this prehistoric brain which, seemingly, has evolved to be myopic with respect to cooperation. Facing this problem, I feel that it’s the psychologist’s job to map out these biases and constraints, and figure out solutions from there. In my research project for Rebuilding Macroeconomics, I investigated how people can be encouraged to cooperate

more if primed to have an in-group feeling just before playing a cooperation game with other players. Using the well-known public goods game (PGG), I tested 150 participants where small groups of five were given a small amount of money and then given a choice: (1) contribute to the public pool, or (2) keep the money. If any player contributed to the public pool, then that amount was multiplied by 1.4 and distributed evenly amongst all players (this was repeated for 30 rounds). Players went home with the amount of money they earned in the game. Overall, participants were divided into three conditions according to types of priming questions. I called them “macro,” “meso,” and “micro”. In the “macro” condition, the PGG was preceded by questions that encouraged thinking about oneself as a “citizen of the world” (i.e. a cosmopolitan viewpoint). In the “meso” condition, the questions encouraged thinking about one’s status as a Middlesex University student. In the “micro” condition, the questions encouraged thinking about oneself only. I predicted that cooperation would be highest in “meso”, based on the presumption that smaller social circles feel more inclusive. In fact, I found that average generosity was highest in the “macro”, second-highest in the “meso”, and lowest in the “micro.”

The result suggests that encouraging players to think in a cosmopolitan style might have some beneficial effect. That said, I observed that players varied widely in their strategies. There was a kind of learning process during the 30 trials, in at least two ways: (1) learning about how the game works and (2) also learning about the behaviour of the other players. Some players were overly generous, donating too much and failing to earn money. Other players chose never to donate money, sometimes earning substantial amounts of money at the expense of others. Most players were somewhere in between these two extremes,

donating only when conditions appeared favourable. To investigate individual differences, I had each player fill out a “zero-sum thinking” (ZST) questionnaire, which measures the tendency to think in zero-sum terms (e.g. “my own gain is necessarily someone else’s loss”). In my study, high-ZST-scorers tended to donate less than low-ZST-scorers. This illustrates how not every player responds the same way to a given piece of encouragement. People are heterogeneous and therefore we should think of heterogeneous ways to promote cooperation.

What makes a person willing to be generous towards a stranger? In my laboratory study, donating to the common pool in a room of strangers was risky, but most players did it anyway. One possible explanation is that players were feeling the emotion of sympathy. If so, then this might provide a clue for how to scale up cooperation to the global level. The philosopher and economist Adam Smith, writing in the 18th century, explained the advantages and disadvantages of feeling great sympathy towards people at a distance. The disadvantage is that we risk misjudging peoples we know little about. The advantage is that we can be more impartial – not caught up in febrile tribalism due to our distance. If nothing else, cooperation at a global scale has the benefit of allowing a more rational kind of sympathy.

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