What is kindness? How do people decide whether to be kind? Can kindness be measured? And just how kind are people?
Kindness can be thought of as actions intended to benefit others at some cost to oneself—an ABC model of kindness.
Kind acts vary in terms of the costs and benefits involved. Some are low-cost, low-benefit (strike up a conversation with someone on your commute). Some are low-cost, high-benefit (help someone cross the street). Some are high-cost, low-benefit (let a colleague take all the credit for a joint project). And some are high-cost, high-benefit (adopt a child).
Previous research suggests that when deciding whether to be kind, people intuitively consider not just the cost and the benefit of the act, but the ratio of cost to benefit. They will perform the act if the ratio of cost to benefit is below a certain level. Most people are willing to perform low-cost, high-benefit acts but not high-cost, low-benefit acts. But people differ. Kinder people are willing to pay a larger cost to provide a given benefit—in other words, they are willing to perform acts with higher cost-benefit ratios. Moreover, people use a different ratio for different recipients—for example, they are willing to pay a larger cost to help people they know (family and friends) over people they don’t know (strangers).
This ratio can be precisely measured using money-sharing tasks (Delton et al., 2023). For example, a person willing to pay a cost of $5 (or less) to provide a benefit of $10 (or more) is making decisions consistent with a cost-benefit ratio of 0.50. Whereas a person willing to pay a cost of $7.50 (or less) to provide a benefit of $10 (or more) is making decisions consistent with a cost-benefit ratio of 0.75. This ratio can be interpreted as how much a person cares about others relative to how much they care about themselves. A ratio of 0.5 means they care about others half as much as they care about themselves. A ratio close to zero suggests that they don’t care about others at all. A ratio above 1 means that they care about others more than they care about themselves.
One study using this method found that, on average, people made decisions consistent with ratios of 1.07 for their mothers and fathers, 0.93 for romantic partners, 0.80 for siblings and friends, 0.53 for acquaintances, and 0.27 for strangers (Forster et al., 2017).
My colleagues and I wanted to see whether the same logic applies when people decide whether to perform everyday acts of kindness.
To do this, we first had 4,801 people rate the cost and benefit of 385 kind acts, and we calculated the cost-benefit ratio of each one (Curry, San Miguel, Wilkinson, & Tunç, 2024). We then used a sample of these acts to create The Kindness Questionnaire, which asks people which of a series of increasingly challenging acts they would perform for others.
One version of The Kindness Questionnaire asked 8,492 people across the U.S. which of a series of 22 kind acts they would perform for their neighbors, alongside a standard money-sharing task (Curry, San Miguel, Wilkinson, & Tunç, 2024). By analyzing their answers— specifically, by identifying the point at which they switched from saying yes to no—we were able to identify the underlying ratio that they were using and put a precise figure on their kindness—a “kindness quotient,” or KQ.
We found that people’s KQs were reassuringly high. The average KQ was 0.74—which means that people care about their neighbors 74 percent as much as they care about themselves. Additionally, we found that their decisions were highly consistent with this ratio—whether an act was above or below their KQ predicted whether they would perform it 87 percent of the time. The results for the KQ were very similar to the results of the money-sharing task, which shows that people apply the same decision-making logic to both financial generosity and everyday kind acts.
There’s no reason to think that a person’s KQ is fixed. It can change, for example, as a relationship improves. And one way to improve a relationship is to be kinder. This new way of measuring kindness allows us not only to predict which kind acts people would perform but also which slightly kinder acts might be within their reach. Previous research suggests that—to many people’s surprise—being a little kinder makes you happier (Curry et al., 2018; Dunn et al., 2008). In the future, we plan to investigate whether providing people with bespoke “recommended acts of kindness” can increase their KQ and make them happier still.
Until then, you can find your own KQ by taking the online version of The Kindness Questionnaire.
