I posted to OSF data, code, and a report for my unpublished "Public Perceptions of the Potential for Human Evolution" project that was from a survey that YouGov ran for me in 2017, using funds from Illinois State University New Faculty Start-up Support and the Illinois State University College of Arts and Sciences. The report describes results from preregistered analyses, but below I'll highlight key results.
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"Textbook" evolution
About half of participants received an item that asked about what I think might be reasonably described as a textbook description of evolution, in which one group is more reproductively successful than another group. The experimental manipulations involved whether the more successful group had high intelligence or low intelligence and whether the response options mentioned or did not mention "evolved".
Here is the "high intelligence" item, with square brackets indicating the "evolved" manipulation:
If, in the future, over thousands of years, people with high intelligence have more children and grandchildren than people with low intelligence have, which of the following would be most likely to happen?
- The average intelligence of humans would [increase/evolve to be higher].
- The average intelligence of humans would [remain the same/not evolve to be higher or lower].
- The average intelligence of humans would [decrease/evolve to be lower].
Percentages from analyses weighted to reflect U.S. population percentages were 55% for the "increase" option (N=245) and 49% for the "evolve to be higher" option (N=260), with the residual category including other responses and non-responses. So about half of participants selected what I think is the intuitive response.
Here is the "low intelligence" item:
If, in the future, over thousands of years, people with low intelligence have more children and grandchildren than people with high intelligence have, which of the following would be most likely to happen?
- The average intelligence of humans would [increase/evolve to be higher].
- The average intelligence of humans would [remain the same/not evolve to be higher or lower].
- The average intelligence of humans would [decrease/evolve to be lower].
Percentages from analyses weighted to reflect U.S. population percentages were 41% for the "decrease" option (N=244) and 35% for the "evolve to be lower" option (N=244), with the residual category including other responses and non-responses.
So, compared to the "high intelligence" item, participants were less likely (p<0.05) to select what I think is the intuitive response for the "low intelligence" item.
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Evolution due to separation into different environments
Participants not assigned to the aforementioned item received an item about whether the participant would expect differences to arise between groups separated into different environments, but the item did not include an indication of particular differences in the environments. The experimental manipulations were whether the item asked about intelligence or height and whether the response options mentioned or did not mention "evolved".
Here is the intelligence item, with square brackets indicating the "evolved" manipulation:
Imagine two groups of people. Each group has some people with high intelligence and some people with low intelligence, but the two groups have the same average intelligence as each other. If these two groups were separated from each other into different environments for tens of thousands of years and had no contact with any other people, which of the following would be more likely to happen?
- After tens of thousands of years, the two groups would still have the same average intelligence as each other.
- After tens of thousands of years, one group would [be/have evolved to be] more intelligent on average than the other group.
Percentages from analyses weighted to reflect U.S. population percentages were 32% for the "be more intelligent" option (N=260) and 29% for the "evolved to be more intelligent" option (N=236), with the residual category including other responses and non-responses.
Here is the height item:
Imagine two groups of people. Each group has some short people and some tall people, but the two groups have the same average height as each other. If these two groups were separated from each other into different environments for tens of thousands of years and had no contact with any other people, which of the following would be more likely to happen?
- After tens of thousands of years, the two groups would still have the same average height as each other.
- After tens of thousands of years, one group would [be/have evolved to be] taller on average than the other group.
Percentages from analyses weighted to reflect U.S. population percentages were 32% for the "be taller" option (N=240) and 32% for the "evolved to be taller" option (N=271), with the residual category including other responses and non-responses.
So not much variation in these percentages between the intelligence version of the item and the height version of the item. And only about 1/3 of participants indicated an expectation of intelligence or height differences arising between groups separated from each other into different environments for tens of thousands of years.
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Another item on the survey (eventually discussed at this post) asked about evolution and racial differences. The reports that I posted for these items removed all or a lot of the discussion and citation of literature from the manuscripts that I had submitted to journals but were rejected, in case I can use that material for a later manuscript.
