Social Science, Mad Science?

I love this recent news story. A respected psychologist at Brown University has shown that simple stimulus-response experiments with known results still produce the expected response (although with a weaker correlation) even if the stimulus happens after the fact. That's right, folks, precognition!

In one experiment, students were shown a list of words and then asked to recall words from it, after which they were told to type words that were randomly selected from the same list. Spookily, the students were better at recalling words that they would later type.

In another study, Bem adapted research on "priming" – the effect of a subliminally presented word on a person's response to an image. For instance, if someone is momentarily flashed the word "ugly", it will take them longer to decide that a picture of a kitten is pleasant than if "beautiful" had been flashed. Running the experiment back-to-front, Bem found that the priming effect seemed to work backwards in time as well as forwards.

The article says the effect was "small but statistically significant," meaning it's pretty unlikely that the relationship is due to happenstance.  That's not scientific proof of precognition, by any stretch, but it does mean the results are worth taking a look at, and others are.

A skeptical approach to the paper that I found pretty interesting can be found here.  I think the take-home point is great:

The real lesson? This is the level of methodological scrutiny every paper should receive, and not just the ones you think are crazy:[...]

But beyond that, I think this article also sums up one of the main reactions to the paper:

I don't believe a word of it because a) let's face it, it's about precognition [...]

Some would say that it is appropriate for scientists to be particularly skeptical about anything supporting stuff we "know is wrong" like paranormal activity. If we think of science as a Bayesian process (which I think we should, but that's a post for another time), then we are essentially updating our beliefs about different explanations of the world as new data arrives.  Our beliefs don't, and shouldn't, shift to whatever the latest results say, because we have a lot of prior knowledge that matters for how we form our beliefs.

That said, though, a Bayesian view of science also implies that total certainty doesn't exist, and that no matter how wacky or far-fetched a theory may seem, we never rule it out completely. We might want to prioritize and spend as little time as possible exploring things that contradicts our prior expectations, but the Dana Skully Scully refrain "It's scientifically impossible!" isn't an acceptable argument in a scientific setting. The sciences don't get to be so dogmatic.

PS - Happy Thanksgiving, folks!