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Cooperation among strangers has increased since the 1950s: study

“U.S. society may have become more individualistic, but people have not.”
People in airport.
The Associated Press/Rick Bowmer

Story at a glance


  • Several factors contribute to the perception that cooperation between Americans may have declined in recent decades. 

  •  But new research published in Psychological Bulletin suggests the opposite has taken place.

  • Authors hope the findings could reflect potential progress in addressing collective societal challenges like climate change.

Although it might seem like the animosity between Americans has swelled in recent years, new research from the American Psychological Association found cooperation between American strangers has gradually improved since the 1950s.

Experts analyzed data from more than 500 studies conducted between 1956 and 2017 involving 63,342 participants. Each study included a lab experiment on cooperation in situations involving conflicting interests — what the researchers defined as social dilemmas. 

Results of the meta-analysis showed no decline in cooperation throughout the study window and instead, revealed a slight increase.

“Some societal indicators (e.g., income inequality, societal wealth, urbanization level, and percentage of people living alone) measured 10 to 5 years prior to measures of cooperation were found to be positively associated with cooperation, suggesting that they may be potential societal underpinnings of increases in cooperation,” authors added. 

However, no causal conclusions can be drawn from these associations, and because the studies focused on responses of college-age individuals, findings may not be generalizable to the whole U.S. population.


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Researchers expressed surprise at the positive findings, given the heightened political polarization, the advent of digital communication and what seems like less commitment to the overall common good seen in recent decades.

“Greater cooperation within and between societies may help us tackle global challenges, such as responses to pandemics, climate change and immigrant crises,” said study author Yu Kou, professor of social psychology at Beijing Normal University, in a press release. 

Previous research has also linked market competitiveness and economic growth with heightened cooperation. As more individuals move into cities and towns, they may come to rely more on strangers.

“U.S. society may have become more individualistic, but people have not,” added co-author Paul Van Lange, professor of social psychology at Vrije Universiteit Amsterdam, in the release. 

Researchers did not measure levels of trust about strangers, and additional studies have found this metric did decrease over the past several decades.

Furthermore, “while Americans’ cooperation has increased over the 61-year period, their beliefs about others’ willingness to cooperate has actually declined,” authors wrote, adding that future studies may be able to better explain this finding.

Reflecting on the effect social media has had on interpersonal communication, researchers concluded by hypothesizing “these technologies may enable and facilitate interactions among strangers, and this may boost cooperation among people within and between societies.”


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