After yesterday’s post about the lack of America’s progress in accepting evolution, I heard from reader Steve Bracker, who claimed that one could perhaps find a glint of hope in the data:
I think you are being a little too pessimistic about evolution acceptance. I’ve used Excel to replot the God had no part in evolution data [see below] with a more sensible vertical scale, and superimposed a linear trendline. Sure, things could be better, but this isn’t “flatlined”. Religiosity is a dire disease; we shouldn’t expect its cure to be quick.
Obviously we don’t want to lean too hard on the trendline as a predictor, but if by 2035 ~20% of the population really is onboard with fully ungodified evolution, that’s a success! Yes, your book may have done its part, perhaps even a vital part. No (the dilemma of, teachers everywhere) you may never really know.
It’s easy to make up all sorts of stories that make the linear trendline completely useless as a predictor. Maybe the goddists finally take over the schools and drive all secular education underground. I can see the headlines: “Santorum lights one for Jesus at NCSE auto‐da‐fe”. Maybe we’ve just picked the low‐hanging fruit, and we will have to work much harder/smarter to pick up the next few percent.
But maybe the linear trendline is too pessimistic. Perhaps people will feel more free to say that gods aren’t needed for evolution any more than they are needed to stabilize planetary orbits. Add just a few percent more vocal nongoddists, and the odds that a given young person can grow up without ever encountering an antidote to his preacher’s mind‐poison go way down. Think of a young epidemic (or forest fire) of respect for reason and evidence! Maybe we’re just creeping up the very early portion of a logistic curve.
Here’s Steve’s plot of the percentage of Americans who, when asked about the evolution of human beings, felt that “humans evolved, but God had no part in the process”:
I noted this trend in my Evolution paper on the topic, but didn’t know if it’s statistically significant. I still don’t: I asked Steve if he could test whether this trend was more than a chance fluctuation, and he responded that:
I don’t know, because I don’t know what the errors are on the individual points. (I didn’t go back to the original data; I just “digitized” the data from the graph you posted.) As a quick check, I generated a dozen dummy data sets, setting each data point to the measured value (from the original graph) + a random number uniformly distributed in (-3, 3). I doubt the survey results are much worse than that. As expected, the slope of the trendline wandered around a bit, but it did stay resolutely positive, sometimes above 0.2315 and sometimes below (0.2144, 0.2529, 0.1762, 0.1471, 0.2415, 0.2725, 0.2190 etc.) So based on this admittedly ruffianly test, I’d say the trend is fairly robust.
For what it’s worth, r2 [the proportion of the total variation in evoution-acceptance explained by the succession of years] is 0.7412 on the original fit.
Using Steve’s best-fit line, I calculated that we’ll finally see 80% of Americans accepting naturalistic evolution in the year 2294. Only three centuries to go, folks!