New study finds opinions on controversial topics evolve through generational turnover, not by people changing their minds

The study, which included data from eight countries over 40 years, found that opinions on sensitive topics like abortion, euthanasia, and homosexuality tend to change more through generational replacement than by individuals changing their minds.

In the court of public opinion, attitudes on controversial topics like abortion, euthanasia, and gay rights have shifted substantially over the past few decades.

But how exactly does this kind of cultural change occur? Do people gradually change their minds over time, or do societies change primarily because older generations are replaced by younger ones with different views?

A new study by researchers at UC Davis and Duke University, published in the journal Evolutionary Human Sciences on April 8, 2024, suggests that the answer depends on how sensitive the topic is perceived to be.

The findings indicate that opinions on controversial ideas, for example euthanasia or same-sex marriage, tend to change more through generational replacement than by individuals actively updating their beliefs.

The Puzzle of Cultural Change

Social scientists have long been fascinated by how societies’ collective beliefs and attitudes evolve.

The dominant theories propose two main pathways for this cultural change.

The “settled dispositions” model argues that our core opinions are formed during our impressionable youth and remain relatively stable throughout life.

In contrast, the “active updating” perspective suggests that people continue to change their minds well into adulthood in response to new information and life experiences.

Previous research, mostly focusing on the United States, has found that the settled dispositions model seems to better explain most long-term shifts in public opinion.

In other words, societies change primarily because older generations with one set of beliefs gradually die out and are replaced by younger cohorts who grew up with different attitudes.

There are some notable exceptions, however, such as the rapid change in American attitudes toward gay rights over the past few decades, which seems to have occurred more through people actively updating their beliefs.

Comparing Change Across Countries and Topics

To better understand these patterns, the authors of the new study analyzed data from the World Values Survey, a large cross-national poll that has been regularly conducted since 1981.

They focused on eight countries – Argentina, Australia, Canada, Japan, Mexico, South Africa, Sweden, and the United States – that had the most complete data across the survey’s nearly 40-year history.

For each country, the researchers examined how opinions changed on 56 survey questions between 1981 and 2020.

The topics ranged from controversial topics like divorce and euthanasia to less-controversial ones, such as the value of independence and hard work.

Importantly, they also collected new data from online participants in each nation on how sensitive these topics are perceived to be.

For example, while discussing the importance of friends might not be seen as taboo, debating the morality of abortion would likely be much more fraught.

The researchers then compared two statistical models for each opinion item.

The first model assumed that beliefs were entirely stable within each generation, and thus that all change was due to the oldest cohorts dying out and being replaced by the youngest ones with different views.

The second model allowed for beliefs to change over time within generations.

By comparing how well each model fit the data, they could infer the relative contribution of cohort replacement versus active updating to changes in public opinion on each topic.

Sensitive Topics Change Differently

The results showed a clear pattern.

For the most sensitive topics, like homosexuality and euthanasia, change occurred overwhelmingly through the process of cohort replacement.

That is, to the extent that opinions on these controversial issues changed over the decades, it was mostly due to older generations with more conservative views being supplanted by younger, more liberal cohorts.

There was much less evidence on these issues of people actively changing their minds as time passed and social conditions shifted.

Interestingly, the researchers found that this was not because sensitive topics were more likely to change overall.

In fact, the perceived sensitivity of an issue had little bearing on how much opinions tended to shift over the years.

Instead, it was that when hard-to-discuss topics did change, they changed through a different mechanism than less sensitive issues.

For the mundane topics that saw sizable shifts in public opinion, change appeared to happen more through people revising their views over time.

Importantly, these patterns were quite consistent across the eight countries included in the analysis, suggesting they reflect general dynamics of how cultural change occurs rather than country-specific quirks.

Whether looking at the role of religious faith in Mexico or attitudes toward abortion in Australia, opinions on the most sensitive topics changed predominantly through population turnover while less fraught topics evolved more via individual mind-changing.

Implications and Future Directions

These findings provide a more nuanced understanding of how new social norms and shared beliefs emerge over time.

They suggest that the path of cultural change depends on the type of issue in question.

For the most unmentionable topics, like the ethics of ending one’s own life, change may be slower and more dependent on demographic shifts.

In contrast, our collective opinions on less emotionally charged issues may be more responsive to social movements or new arguments.

The authors acknowledge that their data cannot definitively pinpoint why this pattern exists.

One possibility is that our views on the most sensitive topics are more central to our identities and are thus more resistant to change.

Alternatively, it may be that we discuss controversial issues less often, and mostly with like-minded others, depriving us of the kind of diverse perspectives that could prompt a rethinking of our positions.

Probing the psychological and social mechanisms behind these dynamics is a ripe area for future work.

Another open question is what exactly makes an issue sensitive in the first place, and whether those perceptions are stable over time or across social groups.

The authors are clear that much more could be done to unpack this construct and its implications for cultural change.

For now, these findings underscore a fundamental truth: on the issues we consider most difficult to hash out around the proverbial water cooler, change tends to happen slowly, one funeral at a time.

“Although beliefs about sensitive issues do not change more than beliefs about mundane issues, they do seem to change more via cohort replacement,” the authors write. “This provides an interesting window into one issue-specific mechanism that might influence how cultural change happens.”

Study details:

Title: “Opinions on Hard-to-Discuss Topics Change More via Cohort Replacement”
Authors: Nicolas Restrepo Ochoa (UC Davis) and Stephen Vaisey (Duke University)
Journal: Evolutionary Human Sciences (Cambridge University Press)
Publication Date: April 8, 2024