Self-interest, not spontaneous generosity, drives equality among Hadza hunter-gatherers

A recent study published in PNAS Nexus suggests that the famous equality seen in some hunter-gatherer societies might be driven more by self-interest than by a natural desire to be generous. When researchers allowed participants to both give and take food from others in a game, they found that equality was usually achieved only when people took from those who had more. This provides evidence that active demands for a fair share, rather than spontaneous charity, help maintain balanced resources in these communities.

The Hadza are an indigenous group living near Lake Eyasi in northwestern Tanzania. Many Hadza still rely on hunting and gathering for a large portion of their food. Like many foraging societies, they are known for their high levels of equality and their practice of widely sharing food across their camps.

Egalitarianism in these groups means they operate without formal leaders and actively resist major differences in wealth or status. For decades, scientists have debated what motivates this widespread resource sharing. Some have argued that humans have an evolved, internal preference to treat others equally and generously.

Other experts suggest that equality is maintained through social pressure. In this view, individuals actively demand food from anyone who has a surplus. Previous economic experiments tested these ideas by giving participants a set amount of resources and asking if they wanted to share.

However, those past games rarely matched the high levels of equality seen in actual Hadza daily life. The design of those earlier games only allowed people to give resources away. This setup does not accurately reflect how food distribution works in the real world.In reality, sharing among the Hadza often involves people asking for or taking food from others.

“Food sharing among many hunter-gatherers is equitable, but alongside ‘giving’ it often also involves ‘taking’ or asking other people for food. In the ethnographic literature this is sometimes called ‘demand sharing.’ Previous economic giving experiments like the ultimatum game and the dictator game allowed people to reallocate resource endowments through giving, but seldom allowed people to ‘take’ from others,” explained study author Duncan Stibbard Hawkes, an assistant professor at Baylor University and editor-in-chief of Hunter-Gatherer Research.

To better understand these dynamics, researchers designed a new experiment that allowed participants to both give and take resources. They wanted to see if realistic levels of equality would emerge when people had the option to take from a peer.

To test these ideas, the researchers conducted a game with 117 Hadza adults from nine different camps. During private interviews away from the main camp, each participant was shown a photograph of themselves and a face down photograph of an anonymous campmate. The use of real photographs helped ensure participants understood they were interacting with actual people from their own community.

Participants were randomly assigned to one of two unequal starting conditions using a coin flip. In the advantageous condition, the participant started with eight tokens and the anonymous campmate started with four. In the disadvantageous condition, the participant received four tokens and the campmate received eight.

The tokens represented dried banana chips, a highly valued food item that provides a significant source of calories. Before the final payout, participants were told they could move the tokens however they wished. They could give tokens to their campmate, take tokens away from their campmate, or leave the distribution exactly as it was.

“We used photographs to show participants that they were giving and taking from other people in the same camps,” Stibbard Hawkes explained. “I think this was the first study to do this. We think this, alongside allowing participants to both ‘give’ and ‘take’ made the game more realistic than many previous economic experiments conducted in the region.”

The researchers found that participants kept more resources for themselves across both conditions. Overall, participants chose to give to the other player in about 31 percent of decisions, while they took from the other player in about 43 percent of decisions. The most frequent choice overall was for the player to leave no tokens at all for the anonymous campmate.

When participants started with more resources than their campmate, only about 41 percent chose to give some away. About 30 percent of people in this advantageous position actually took tokens from their campmate to increase their own wealth. Equality was rarely reached when people started with a surplus.

Behavior shifted when participants started with a disadvantageous distribution. In this scenario, nearly 59 percent of participants chose to take resources from the other player. When people took tokens to fix a personal disadvantage, the final distributions closely resembled the high levels of equality seen in real Hadza food sharing.

“Our primary manipulation strongly influenced game decisions,” Stibbard Hawkes told PsyPost. “In terms of the actual decision task, participants in the advantageous and disadvantageous inequality conditions were essentially playing the same game as each other: choosing the allocation patterns of 12 tokens, a fairly standard dictator game design. However the framing of this study – either advantageous and disadvantageous inequality, had a strong effect on decisions. So this primary manipulation was highly significant and exemplifies the importance of ‘framing’ in economic experiments of this type.”

These findings suggest that equality in these communities does not primarily come from unsolicited generosity. Instead, it tends to arise because individuals who have less actively demand or take from those who have more. The researchers noted that this behavior aligns closely with real ethnographic observations of daily camp life.

“Descriptions of hunter-gatherer egalitarianism sometimes gives the impression that these societies are atypically generous and public-spirited because they have not been corrupted by ‘modernity’ — this is the plot of a film called The Gods Must Be Crazy, where a coke bottle lands in the Kalahari desert and causes all sorts of trouble,” Stibbard Hawkes told PsyPost.

“Pushback against this ‘noble savage myth’ has led some researchers (like Graeber and Wengrow) to dismiss the idea of egalitarian societies entirely. But in fact, Hadza food sharing is very egalitarian and people give a lot of the food they procure away. Forager food sharing absolutely results in more equitable ‘egalitarian’ outcomes than we see in many market-oriented societies.”

“What I want to stress is that this isn’t because hunter-gatherers are any more or less generous than any other group of humans,” Stibbard Hawkes explained. “Some people were generous in these games, some weren’t. Instead, people secure equality for themselves by exerting pressure for others to share – taking as well as giving. Here, taking was key. This matches ethnographic accounts, which I have discussed more in another recent article, here.”

The scientists also observed distinct demographic differences in how people played the game. Men and younger individuals were more likely to give away resources when they started with an advantage. Women and older individuals tended to keep more for themselves across both conditions, which matches patterns seen in traditional foraging labor divisions.

The researchers also examined how exposure to outside cultures influenced decision making. Participants completed a survey measuring their experiences with formal schooling, wage labor, and national Swahili culture. Those with higher exposure to outside cultures were moderately less likely to fix disadvantageous inequality.

“In other words, they were more tolerant of others having more than them – which makes sense given that traditionally the Hadza do not keep much personal property,” Stibbard Hawkes said. “However, this effect was only modest.”

This increased tolerance for inequality might reflect a shift in traditional sharing practices. As people interact more with market economies, they often begin to accumulate more personal property. This suggests that changing economic landscapes can slowly alter how small communities enforce equality.

Readers might be tempted to interpret these findings as evidence that hunter-gatherer equality is a myth. The scientists emphasize that this is a misinterpretation. Egalitarianism in these societies is very real and results in highly equitable living conditions, but it requires active effort.

“I’ve seen coverage of my recent work claiming that ‘egalitarianism isn’t real’ or hunter gatherers ‘aren’t actually egalitarian,’” Stibbard Hawkes said. “This isn’t what I’m saying! I think hunter-gatherers are (relatively) very egalitarian.”

“However, egalitarianism isn’t because everyone is exceptionally generous or noble. People often have to secure a fairer share for themselves. Often hunter-gatherer egalitarianism can be very stressful and there can be friction, complaining and grumbling – as there often is when people in any society seek more equitable outcomes for themselves. But egalitarianism is real, we just often misunderstand it.”

The study does have some limitations that provide avenues for future research. Because the experiment was anonymous to protect privacy, it removed the public scrutiny and social pressure that normally guide food sharing in a real camp. Future studies could explore how the watchful eyes of third parties influence these sharing decisions.

Additionally, the game relied on a specific currency, dried banana chips, which might hold different value than freshly hunted meat or gathered berries. Scientists plan to continue this research by directly comparing individuals’ choices in experimental games with their actual sharing habits over time. They also hope to study how ongoing integration into cash markets might continue to shift traditional sharing practices.

The study, “The “I” in egalitarianism: Hadza hunter-gatherers averse to inequality primarily when personally unfavorable,” was authored by Kristopher M Smith, Duncan N E Stibbard−Hawkes, Eugen Dimant, Ibrahim A Mabulla, Cristina Bicchieri, Coren L Apicella.