How the mind decides to help and harm: Welfare tradeoffs among US and Argentine students and members of the Shuar and Tsimane of the Amazon
– by Andrew W. Delton. Photo credit by Arnulfo Cari Ista: author Adrian Jaeggi leads a member of the Tsimane community through a task measuring helping
“It is interesting to contemplate an entangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth” (Darwin, 1859, Origin of Species). As we stand beside a river and gaze at such a bank, images enter our minds unbidden. We need not cogitate to see the warblers and the dragonflies, the churn of the water, or the moss-covered rocks. Our perception of the scene feels unmediated.
This, we know, is an illusion. Vision arises from a fiendishly complicated set of adaptations, including eyes for capturing photons bouncing off nearby objects and computations performed by the nervous system for turning this raw sensory data into a useful picture of the world.
Feelings, too, enter our minds unbidden. When our child comes crying to us with a scraped knee, warmth rises in our breast and we want to console her. When a friend needs us to cover the check, we are only too happy to do so. When an enemy commits a faux pas, a bolt of cold glee takes hold—this accidental gift will help us burnish our reputation at his expense.
Desires to help or harm also feel unmediated. But, as with vision, are these desires also created by complex and largely unconscious computations? Our team, including Daniel Sznycer, Adrian Jaeggi, Julian Lim, and other collaborators, designed a series of studies to find out.
We studied how people decide to help or harm, specifically whether they do so with precision. We suspected that the felt simplicity of these desires is actually created by computations involving precise variables. These variables encode how much a person is willing to trade off their own welfare to help or hurt another person. Given their function, we call them welfare tradeoff ratios.
In our studies your task was to decide whether to give one sum of money to a specific other person (perhaps your best friend or an acquaintance) or to keep a different sum of money for yourself. For instance, would you take $54 for yourself or give your friend $37? Probably you’d take the $54. But what if you would get only $46? Or $39? Or $31? Now you might switch to giving the $37 to your friend.
We had participants make many decisions (in some cases up to 60). Across decisions, we varied exactly how much money was at stake for both people. In most, you decided whether to pass up money for yourself to give to the other person—helping. More rarely you decided whether to pay to prevent the other person from getting money—harming.
To measure precision, we examined how consistently participants chose who got what. For instance, if you would forgo $46 to give your friend $37, it would be inconsistent to later keep $31 for yourself rather than give your friend $37. Why pass up a large amount only to keep a smaller sum? If precise variables for welfare tradeoffs create desires to help or harm, we predicted that people would make few inconsistent decisions. Were we correct?
First, we studied university students in the United States and Argentina. As suspected, they were very consistent when deciding to help or harm. We measured consistency in two ways. One way was strict, requiring that people make no inconsistent choices at all in a set of many decisions. On this measure, if people were responding randomly, then they would be consistent only 1% of the time. In fact, our students were consistent 70% of the time or more. Our second measure was forgiving and did not require perfection. Here, random choices would lead to consistency about 70% of the time. In fact, on this measure, students were consistent 94% of the time or more.
We also found that people were more generous with friends than acquaintances. This didn’t surprise us. But it shows the students understood our task and took it seriously.
We found what we expected. Yet students are strange. They have undergone years of formal schooling in math. They live in advanced, industrial democracies. Perhaps something about their evolutionarily unprecedented lives caused them to be so precise—rather than, as we hypothesized, a universal psychology for making welfare tradeoffs.
To find out, we conducted similar studies among small-scale communities of people who forage and farm: the Shuar of the Ecuadorian Amazon and the Tsimane of the Bolivian Amazon. Did we find similar results among people who lead very different lives from university students?
Yes. Among the Shuar, on our strict measure of consistency, they were between 25% and 41% consistent. This is lower than among students but to be expected: We gave members of Shuar more decisions, making the task much harder. (Had they responded randomly, they would have been consistent a mere 0.05% of the time; recall that for students the number was 1%.) On the more forgiving measure, members of the Shuar were consistent 85% of the time (random responding would have been 68%).
Unlike the students, Shuar participants were not more or less likely to help or harm different categories of people—whether siblings, friends, or acquaintances. This surprised us but it could make sense given recent violence in the area; for protection, members of the Shuar might have been interested in shoring up connections even with distant associates.
Finally, we studied members of the Tsimane. The method we used with them did not allow us to calculate consistency. But they had no problem making many tradeoffs between themselves and other people. And like the students, the Tsimane participants were more generous with close others than distant others (for instance, community members versus outsiders).
Altogether, in three of three tests of quantitative consistency, university students from the US and Argentina and members of the Shuar made tradeoffs with precision. Members of the Tsimane found similar decisions easy and intuitive.
Desires to help or harm appear generated by precise variables in the mind.
Read the article: Delton, A.W., Jaegii, A.V., Lim, J., Sznycer, D., Gurven, M., Robertson, T.E., Sugiyama, L.S., Cosmides, L, & Tooby, J. (in press). Cognitive foundations for helping and harming others: making welfare tradeoffs in industrialized and small-scale societies. Evolution and Human Behavior.