Tuesday, September 15, 2026

Responsibilities in close social relationships explain differences across cultures

Study untangles decades of conflicting findings on identifying collectivism

Arizona State University

Do you think that a person who reorganizes their life so that their aging parents can live with them would be likely to push another out of the way on the subway? What about greeting strangers with a smile?

The answers to these questions are at the heart of a puzzle social psychologists have been debating for 30 years: how to best understand differences between cultures.

Cultures are generally classified as interdependent or independent, and the prevailing idea that defines cultural differences is whether people value others more than the individual, a concept called collectivism. For decades, the surveys that social psychologists used to measure collectivism have generated contradictory and nonsensical findings, such as repeatedly labeling Western cultures, such as the United States and United Kingdom, as more interdependent than East Asian countries, such as Japan.

In a study published in Nature Human Behavior on September 15, an international research team has shown that the responsibilities people hold in close relationships are what reliably differentiates Eastern and Western cultures and form the foundation of collectivism. The researchers developed a survey to measure this phenomenon, which they termed responsibilism.

“Culture is everywhere, and because it is everywhere, understanding it unlocks opportunities all around us,” said Thomas Talhelm, lead author on the study and the new Robert Cialdini Endowed Professor in Social Influence in the Arizona State University Department of Psychology.

“This work on responsibilism has the potential to give insight to people who straddle cultures, including children of immigrants navigating conflicting expectations at home and in school, teachers who adjust their instruction based on students with different value sets, or doctors who have to help people make decisions for sick family members.”

The importance of who and what

Talhelm spent 7 years living in China, which inspired and shaped this work. While living in Beijing, he experienced competitive jostling on the subway and received suspicious frowns when he smiled at people he passed on the street. At first, these behaviors seemed to be inconsistent with China having a collectivist culture — until he realized the common thread running through all these interactions was that they were between people who did not have close relationships with each other. Talhelm thought this thread might be contributing to contradictory findings about collectivism.

To test this idea, the research team set up the new survey questions to drill down into the responsibilities that come with having a close relationship with someone. The questions were specific about who was involved and what was happening, such as scenarios about keeping aging parents at home or going to a party and talking to people you don’t know to make new friends. The researchers specified the closeness of the people involved, whether it was a parent, coworker or stranger, and the circumstance and actions involved. Separately, the survey included questions about emotions, such as how people felt about others who were close to them or part of a larger group.

This responsibilism survey was translated into 45 languages and given to 12,247 people in 100 different cultures. The sampled countries covered 90 percent of the world’s population.

The new survey reliably separated East Asian and Western cultures, which previous work struggled to do. Countries in Africa, the Middle East and Asia scored higher in responsibilism than North America, Europe and Australia.

“Individualism versus collectivism explains differences between continents, nations, and even groups within nations,” Talhelm said.

Responsibilism predicts societal differences and individual behaviors

Collectivist cultures tend to do well on measures of social order, but those come at the cost of individual rights and openness, Talhelm explained. Countries that scored high on the responsibilism survey have lower democracy scores and more corruption in government. They also have fewer policies favoring immigrants, such as right to work and family reunification, and fewer patents and sales of creative goods. The survey also found differences in public health, with countries scoring high having fewer deaths per capita from COVID-19 and lower rates of drug abuse.

Scores on the responsibilism survey also predicted behaviors at the individual level, with higher scores being associated with living with extended family members and being willing to lie in court for a close friend. By contrast, lower responsibilism scores, which are associated with more independent cultures, were associated with being likely to return a lost wallet — and with fewer parking tickets given to United Nations diplomats.

Diplomatic immunity means that parking tickets do not have to be paid, but despite the nonexistent consequences, the number of parking tickets among U.N. diplomats varied widely, ranging from none to 246 per diplomat over a 4-year period. Violating parking rules means that someone else, who is likely unknown to the driver, was unable to park. The distance of this relationship likely influences the choice of where to park, and the diplomats with the most parking tickets from near the U.N. were from countries with high responsibilism scores.

This work was conducted with researchers from Northwestern University; Hubei University in Wuhan, China; ESADE Business School in Barcelona, Spain; Sultan Qaboos University in Muscat, Oman; Maqsut Narikbayev University in Astana, Kazakhstan; Aarhus University in Aarhus, Denmark; and Wenzhou Kean University in Wenzhou, China. The research was supported by the William Ladany Faculty Scholar fund and the National Science Foundation of China.

Journal

Nature Human Behaviour

DOI

10.1038/s41562-026-02525-1

Method of Research

Survey

Subject of Research

People

Article Publication Date

15-Sep-2026

Why most rivers don’t respond to storms the same way twice

A global analysis of catchments underscores the complexities of modelling river run off and flooding—and provides new tools for hydrologists

University of British Columbia

Forested catchments on Vancouver Island's west coast — image:
Forested catchments near Bamfield, on Vancouver Island's west coast, where rain arrives almost every week in winter. Simple catchments like these are rare worldwide, but this stretch of coast holds one of the largest concentrations anywhere in the study. (University of British Columbia)
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Credit: University of British Columbia

The same amount of rain falling on the same landscape at different times can send very different amounts of water into its rivers, according to a new study in Nature Water. The research offers a global picture of how catchments behave—not where rivers are or how much water they carry—but how consistently landscapes turn rainfall into river flow.

“We often imagine a catchment as a pipe—put in a certain amount of rain and get a predictable amount of runoff,” said Dr. Ali Ameli, a hydrologist at the University of British Columbia (UBC) and lead author of the study.

“But most catchments behave more like dynamic systems with a memory. How much of today’s rainfall becomes runoff and reaches the stream depends on both the conditions created by earlier weather and which parts of the landscape supply water to the river during the storm.”

Drawing on more than two million rainfall–runoff events, the researchers assessed the behavior of more than 80,000 catchments across 97 countries. They found that complex behavior, in which similar amounts of rainfall can generate very different runoff responses, covered 87 per cent of the land area evaluated in the study, some 121 million square kilometers. Simple catchments, in which a given amount of rain delivers roughly the same amount of water to the river every time, covered just 1.5 per cent.

A third group, which the researchers call intermediate, sits between the two. They have more than one stable way of responding to rain—perhaps two or three—and switch between them.

Complex catchments dominate across Africa and much of Asia, across most of France, Spain, eastern Germany and Denmark, across the central United States and across most of South America.

Simple catchments are far rarer, concentrated along the Coast Mountains of Canada’s British Columbia and the U.S. Pacific Northwest, with smaller pockets in the northern and western United Kingdom, parts of Ireland and northern Spain, and in Tasmania and New Zealand. Intermediate catchments are common across the eastern United States.

The team has released an interactive global map of the results, along with a free web application that returns a classification for any catchment boundary. Both are publicly available.

It is not just how much rain falls, but how often

The strongest factor separating simple and complex catchment behavior was the frequency with which meaningful rainfall occurs over time.

“It’s not simply the amount of rain that matters; it’s also the rhythm of rainfall,” Dr. Ameli said. “Persistent rain keeps the landscape in a more consistent state. When wet and dry conditions alternate, the same catchment can behave very differently from one event to the next.”

Where rain arrives regularly, soils, subsurface stores and pathways connecting the landscape to the stream remain in similar states from one storm to the next. In these catchments, a comparable amount of rain is more likely to generate a comparable amount of runoff. The rain-soaked coast of Canada’s British Columbia is one of the clearest examples in the study.

Where rain is less persistent, a catchment repeatedly moves between wet and dry conditions. A storm arriving after a dry period may soak into soils and subsurface stores while sending relatively little water to the river. A similar storm arriving when the landscape is already wet can send a far larger share of that rain downstream.

Impact of overall water availability, landscape

The researchers also found that a region’s overall water availability strongly distinguishes simple from complex catchments.

They examined this using measures including an aridity index, which compares how much water the air can draw off a landscape with how much rain actually falls on it, and the long-term balance between rainfall and the water that evaporates or is taken up by plants.

Catchments with simpler, more consistent behavior were generally found in wetter and more humid conditions. Complex catchments were more commonly associated with drier conditions, where less water remains after evaporation and plant use are accounted for.

These findings show that overall water availability establishes the broad climatic setting, and that rainfall rhythm indicates whether the landscape is likely to remain in a stable hydrologic state or alternate among different states.

Climate was the dominant influence, but the physical character of a catchment helped refine its behavior at local and regional scales. Simple catchments tended to occur in steeper terrain. Steeper slopes can move water rapidly and maintain more direct connections between the landscape and the stream, contributing to a more consistent runoff response.

A new way to understand the world’s catchments

The study and map give hydrologists a common language for comparing catchments in different parts of the world. Two catchments on opposite sides of the planet may convert rain to runoff in the same way, and the classification makes that visible.

It also offers a practical guide to how a catchment should be represented in a computer model. A simple catchment can be captured by a straightforward model. A complex one needs a model that allows different parts of the landscape to take the lead at different times.

The research was conducted by Dr. Ameli and Hamed Sharif of UBC and Dr. Jeffrey McDonnell, affiliated with the University of Saskatchewan, North China University of Water Resources and Electric Power, and the University of Birmingham.

A forested, steep catchment on Vancouver Island, British Columbia, where rain arrives almost every week in winter, and a dry shrubland catchment near Jacobina in Bahia, northeastern Brazil, where long rainless spells fall between storms. Color shows land cover, blue lines are the stream network, and the red circle marks the outlet each catchment drains into. Relief is exaggerated 1.9 times (Ali Ameli, University of British Columbia).

Credit

Ali Ameli, University of British Columbia