Feeling the future

[winterkoninkje]

Hat tip to homasse:

Experimental evidence for precognitive ability

The paper, due to appear in the Journal of Personality and Social Psychology before the end of the year, is the culmination of eight years' work by Daryl Bem of Cornell University in Ithaca, New York. "I purposely waited until I thought there was a critical mass that wasn't a statistical fluke," he says.

It describes a series of experiments involving more than 1000 student volunteers. In most of the tests, Bem took well-studied psychological phenomena and simply reversed the sequence, so that the event generally interpreted as the cause happened after the tested behaviour rather than before it.

The alternative interpretation of this work is that the interpretation of previous studies as causation (e.g., typing a random selection of words causes improved recall of those words in a second task) is flawed. Technically all that has been found is that there's a typing-then-remembering correlation (in previous studies) and a remembering-then-typing correlation (in this study). Correlation does not imply causation; so even though the causative story is extremely plausible in the old studies and no non-precognitive causative story seems plausible in the current study, that doesn't necessarily mean that either causative story is correct.

For all the hard scientifical review the preprint is receiving, I'm surprised that this point hasn't been mentioned anywhere. IMO, refuting the standard causative story would be just as fascinating as supporting the precognitive story. It would imply that there are macro-scale quantum effects (e.g., where remembering words from a list and typing random words from that list are coupled), whereas it has long been believed that quantum effects only arise at scales too small to be detected by unaided human perception. If there really are macro-scale quantum effects, it seriously fucks with both physics and philosophy (to say nothing of psychology). Whichever way it turns out, it's still awesome.

Edit (2011.06.29): Here is an excellent examination of a lot of the debate this article caused.

Comments

[tim]

From this dude's home page:
"Are Self-identified Bisexuals Just Lying to Us—or to Themselves?"

0_o

(The contents of the link are just as 0_o as the title would imply.)

Also, I haven't read this carefully, but it looks like some people have already called shenanigans:
http://dl.dropbox.com/u/1018886/Bem6.pdf

[winterkoninkje]

There are a bunch of folks who'd like to shoot down Bem's article because of their anti-psychic position. That counter article is taking much the same attitude to it as when I first read about it. That is, given the fabulous methodology of just reversing the order of standard experiments, I figured that the main point Bem was aiming to make was to shoot down standard psychological analyses (and if support for parapsychology comes out from it, all the better). I mentioned the causality issue, and the counter article is mentioning p-values vs t-tests.

Unfortunately, reading the abstract of Bem's paper, it's clear that he's actually trying to show evidence for parapsychology, as opposed to making the parapsychology-or-standard-methods-are-broken argument. Unless my subtlety-dar is broken.


From this dude's home page: "Are Self-identified Bisexuals Just Lying to Us—or to Themselves?"

O_o indeed.

[winterkoninkje]

From this dude's home page: "Are Self-identified Bisexuals Just Lying to Us—or to Themselves?"

To be fair, if you read the posting it seems rather reasonable and its thesis doesn't match the title. Indeed, Bem is arguing against both sides of the disjunction. From the tone of the writing and the comment that it was posted online to Sexnet, I'd guess that the title comes from the discussion thread rather than from Bem himself.

[tim]

I didn't find it reasonable. After all, he basically starts by agreeing with the premise that bisexuals can't be trusted to identify their own sexual orientation accurately. His assumptions were highly suspect: it only makes sense to draw his conclusion that "identifying oneself as bisexual is a straight or gay person's way of reconciling their attraction to one person who isn't their preferred gender" [I'm paraphrasing] if you start by assuming that "straight" and "gay" are the only real sexual orientations. His reasoning was baroque and it's very strange that he chose to link to this particular post on his home page. I've been in a lot of Internet arguments, and there were some where I even thought I wrote something clear and insightful, but I don't link to any of them on my professional home page.

[winterkoninkje]

Hmm, that wasn't how I read it.

I should like to offer an alternative perspective on a subset of those men and women who describe themselves as bisexual, an alternative to the unflattering view that they are all lying, deceiving themselves, or “transitioning” to homosexuality.

That sounds a lot like he's disagreeing with the view that bis are lying etc, not that he's agreeing with the "unflattering view". Granted, he does go on to state that he believes many self-described bisexuals are predominantly gay/straight. But, the reasoning he presents ---however suspect it may be--- does match many of the stories I've heard from friends over the years about their own lives and trying to understand whatever their sexuality is. It's certainly not the lived experience of all bisexuals, but it does capture something about many people who identify thus.

It's well documented (to the extent that any research on sexuality can be trusted) that there is a discrepancy between those who identify as bisexual and their self-reports of how attracted they are to each sex and what sorts of relationships they've been in. The conventional analysis of this discrepancy is the "unflattering view", which I think is completely wrong as well as grossly insulting. However, the discrepancy remains. The idea that romantic and sexual drives are essentially distinct matches my own experience as well as those of many of my friends, and it does offer a non-insulting explanation for the discrepancy. Thus, the blurb seems fairly reasonable to me. I don't see him assuming that only gay and straight orientations exist, so much as assuming that self-reports of attraction and behavior come out as mostly heterosexual or homosexual.

Granted, toward the end where Bem starts hypothesizing about differences in men vs women re these drives, that part is hokum trying to justify the cis-patriarchal ideology of men vs women. But still the whole thing still reads to me like he's arguing against the "unflattering view" and positing a framework which seems to match the lived experiences I've been privy to.

Yeah, linking to it from his homepage is a bit peculiar.

[lederhosen]

I'm a bit dubious of the stats here:

"I purposely waited until I thought there was a critical mass that wasn't a statistical fluke," he says.

That bit there is a red flag to me. The decision about when to stop an experiment should NOT be based on the significance figures for results to date, otherwise you're at great risk of cherry-picking.

If I run a random number generator and keep rerunning the p-value, I will see that drift all over the place. Every so often, it'll drift into 'significant' territory; as the trial goes on that drift will slow, but wait long enough and you can meet any significance threshold you like.

If you have a few hundred colleagues running similar experiments, all holding off on publishing until they get a strong finding, you can get some *really* impressive-looking results.

[tim]

...which would certainly explain why no one else has been able to reproduce his results.

[lederhosen]

Now I check the link you posted, it covers this and some other cherry-picking issues really well.