by Thomas Richardson

Men are taller, bigger, stronger and more warlike than women. Or to use the academic term; men are the formidable sex. This is true across the vast majority of human cultures and time periods. In the last 2 decades many studies have investigated how we got like this, and how it affects our minds and behaviours today.

Formidable men in our ancestral environments would have likely got what they wanted more than less formidable men. They could simply threaten anyone who attempted to stop them getting their way. Others may have also wanted to appease these men, as they make powerful allies. One theory goes that this would lead to men evolving to calibrate their demands to their formidability. Big and tough? Demand more. Small and weedy? Maybe keep your demands close to your underdeveloped chest.

How would this play out in our modern societies? One prediction is that formidable men might prefer a society that was less equal, for example by opposition to government redistribution of wealth. Many people are happy with inequality if they’re the ones on top, and in ancestral societies, formidable men would have often been up there. On the other hand, some researchers argued that this trend might reverse if the big bloke was poor. Then they might forcefully argue for equality and wealth redistribution, as it would benefit them. Put simply: more formidable men should argue more for their own interests.

This theory might resonate with you. Most of us know a big, strong, entitled jerk in our own lives. But if you’re a bit sceptical of this theory, you’re not alone; I was too when I first read the research. But there seemed to be quite a few studies showing that more muscular men were averse to equality and government wealth redistribution. Some studies found it depended on their own wealth. The studies had cross-cultural samples, some quite large. None of that means the research should be uncritically trusted, but these are generally good signs. So, I was intrigued, and thought I’d do some work on it myself.

One thing previous studies hadn’t tested as much was whether the theory applies to the other indicators of formidability: height. The theories described above would predict that taller men would be less supportive of equality. It might also predict that this relationship would depend on wealth: tall, poor men would support equality, as it would be in their best interest, whereas tall, rich men would oppose it.

In my paper, I set out to test whether these hypotheses applied to height as well as muscularity. To do this I used data from the European Social Survey. This survey collects data on attitudes and behaviours (mainly relating to politics) for ~2000 people representatively sampled from each European Country. They’ve done this every 2 years with only slight modifications to the questions, going all the way back to 2002! Luckily, in wave 7 they obtained data on respondent’s height, giving me free, easy access to a rich dataset of 27,000 representatively sampled people. It really is a fantastic resource, and I advise researchers to check it out. Datasets like these are underutilised by evolutionary social scientists, and have a lot of potential. Because while these datasets have been bled dry by political scientists and economists, these researchers lack the evolutionary perspective, and so there are many hypotheses they wouldn’t think to investigate. Plus, in the midst of a global pandemic, where else are we going to get data?

One of the difficulties with this type of research is establishing causation. A correlation between muscle mass and political attitudes doesn’t tell us whether the muscle mass causes us to have the attitudes or having certain attitudes cause us to develop our muscles. Studying height partially gets around this, because men can’t really change their height. As such, the causation between formidability and attitudes can only go one way.

But this still leaves the problem of third variables: perhaps something causes some men to be taller/stronger and also causes them to hold more self-serving attitudes. A related issue was alternative mediators: perhaps height does affect attitudes towards wealth redistribution, but it’s not caused by increased self-interest. It might just be because taller people are more educated or because they’re older. To make my case I’d have to control for these third variables and alternative mediators to make any proper conclusions. Getting at causality with observational data can be done but is certainly a challenge! In this study, I controlled for age, income, years of education, conservatism and whether someone had a position of authority at work.

The evidence supported both hypotheses about equally:

1. Overall, taller people endorsed anti-redistribution attitudes more than shorter people.
2. But the effect of height also depended on wealth. Among richer people the trend held, but among poorer people the trend reversed. For poorer people, being taller meant more support for government redistribution of wealth. We could put this interaction effect another way: though richer people supported redistribution less, the being tall made the effect even stronger.

Notice how I’ve written ‘people’ not ‘men’. One result that was confusing, and not fully consistent with the theory, was that women showed the effects as strong as men did. Most women aren’t in the same ballpark as men when it comes to formidability, and historically haven’t engaged in large amounts of violent competition compared to men. So we wouldn’t expect to see the same effects in women. But I did. I list some possible reasons in the paper, but ultimately I can’t explain this result. Sometimes as a scientist you have to raise your hands and admit you don’t know.

With the main results established, I ran as many robustness checks as I could think of to see how strong the result was. There are often many ways to use statistics to test a particular hypothesis, and there isn’t always a clear right answer. Rather than choosing (and perhaps risking bias), one option is to run them all and see whether a hypothesis is supported most of the time. So that’s what I did, and the results held pretty well, increasing my confidence in the result.

One thing to note though is that the effects I found were very small. Small effects can matter, and small effects on the political attitudes of a whole country may result in a lot of votes. Also, some argue that most effects we can expect to see in behavioural science are small. But how small is too small? I don’t really know. A question that has seen a lot of discussion in recent years is how we define a ‘smallest effect size of interest’, where any effect smaller than this may as well be 0. Working out the smallest effect size of interest for hypotheses in the evolutionary social sciences will likely require refining our theories a lot more than many of us currently do, to the point where they make concrete predictions about effects we’d expect to find in our studies. This sounds hard, and it is, but will certainly be worth it.

So to sum up: In a large, representative sample of Europeans, I find that taller people are less supportive of government redistribution of wealth, especially if they are also wealth themselves. If you want to learn more, give the paper a read, and take a look at the data and R script if you’re curious about the details of the analyses. If you have any questions or comments, I’d love to hear them!

Read the paper: Height is associated with more self-serving beliefs about wealth redistribution

by Paul Deutchman

Imagine that you are at an academic conference with a friend. As you walk into the convention hall one morning, you see a table covered in Danish pastries. You grab a couple pastries and put them on a plate. Before you can even take a bite, you remember that you left your poster in your hotel room upstairs. The poster session is about to start so you leave your pastries with your friend and run to your room. When you come back down, you see that your friend has eaten one of your pastries. You would probably be less than thrilled with their friend, maybe even a bit disgruntled. Now imagine a slightly different version of that scenario. This time, before you can grab any pastries you realize you forgot your poster and run upstairs to get it, but not before asking your friend to grab a few for you. When you come back to the convention hall, you see that your friend has a plate full of Danishes for herself, but only grabbed one for you. This might also make you kind of mad, right? However, it is less clear why that is the case in this scenario; your friend didn’t steal your pastries, but it still feels like they did something wrong.

This example captures two of the main, proximate motivators of punishment: revenge, the desire to reciprocate harm, and inequity aversion, the dislike of unfairness. What the latter example highlights, is that unfairness alone can be upsetting enough to motivate punishment. Understanding the motivations behind punishment is an important topic because understanding what motivates punishment can inform our understanding of the functions of punishment and why it evolved in the first place. Revenge-based punishment serves an important deterrence function by discouraging those that harm us from doing so again in the future. On the other hand, inequity-based punishment may serve an important leveling function by ensuring that we’re not worse off than others and potentially giving us a competitive edge, or at least preventing others from gaining too much of a competitive advantage.

Previous research on the relative importance of inequity aversion and revenge has been mixed – some work has found that punishment is motivated primarily by revenge, while other work has found that it is motivated primarily by inequity aversion. Recent work has added more nuance to this debate, finding that punishment is mainly motivated by revenge, with inequity aversion only factoring in as a secondary motivation when people experience losses. However, it remains unclear whether inequity aversion matters in the absence of losses. In other words, do people ever punish others simply because of unfair outcomes?

In our study, we addressed this question by pairing up two people who have never met and having them play an online economic game for real money. The game had two conditions, a Take condition and an Augment condition. In the Take condition, as in the pastry example, one player could steal money from the participant or do nothing. In the Augment condition, one player could give money to the participant at no cost to themselves or do nothing. By examining cases where a player chose to not give this money to the other player, this condition allowed us to investigate whether inequity aversion motivates punishment in the absence loss. Specifically, because the participant was not harmed by the other player in this condition, the only motivation for punishment is to reduce inequity.

Importantly, we also varied the level of inequity participants experienced by manipulating the starting endowments they received at the start of the task: some participants had more (advantageous inequity), the same amount (equality), or less than the other player (disadvantageous inequity). This resulted in participants experiencing different degrees of inequity, which was either worsened, improved, or unchanged depending on whether their partner decided to steal (Take condition), give (Augment condition), or do nothing, respectively. After learning about the other players decision and seeing their relative endowments, participants could punish by paying a cost to reduce the other player’s earnings.

In support of past work, we found that people mainly engaged in punishment when the other player stole from them, suggesting that punishment was motivated primarily by revenge. However, unlike previous work, we also found that, regardless of whether the other player stole from them, participants were more likely to punish when they had less money than the other player as compared to when they had the same amount or more. This finding—that people punished when they experienced inequity but not losses—offers evidence in line with the idea that punishment is motivated by fairness concerns.

Furthermore, our data provide some support for the theory that punishment serves a competitive function by increasing relative payoffs and status. Because punishment in our study used a 1:3 fee-to-fine ratio (i.e., the ratio of punishment’s cost to damage), it is difficult to disentangle any punishment from a competitive motivation to increase relative payoffs. Additionally, a small minority (5-10%) of participants in our study punished the other player for choosing the prosocial option (not stealing or augmenting), even when they had equal or slightly larger endowments. Together, these results potentially suggest that some participants were motivated to punish antisocially, perhaps out of spite or a competitive motivation.

Findings from our new study are exciting because they offer strong evidence that there are different motivations for punishment. That punishment is motivated by both revenge and inequity aversion suggests that punishment likely evolved for multiple functions—both a deterrence function and a fitness-leveling function. That punishment can serve both functions highlights how evolution can design one behavior to serve different goals.

Future work should examine cultural differences in the motivations underlying punishment. We know there are meaningful differences in punishment across societies, and it will be important to explore the prevalence of revenge and inequity aversion motivations in these countries. For example, inequity aversion might motivate punishment more in societies that lack strong formal enforcement mechanisms and where there is more intense local competition for resources, environments where fitness-leveling might be an especially adaptive strategy.

In sum, our work suggests that punishment is motivated by different factors—people are primarily motivated by the desire to seek revenge, but also to some extent by the desire to reduce inequity. These findings underscore the multifaceted functions punishment evolved to serve and highlight the need for greater research on punishment across different societies, especially in non-WEIRD societies.

Read the paper: Punishment is strongly motivated by revenge and weakly motivated by inequity aversion