I always knew they’d prove precognition was real!

Paul Raven @ 17-11-2010

Well, not really (or at least not for a long time), but I couldn’t resist the title. So, here are some bits from Wired Science‘s piece on Daryl Bem’s new paper entitled “Feeling the Future: Experimental Evidence for Anomalous Retroactive Influences on Cognition and Affect”… which purports to contain experimental evidence of precognition in human minds.

Bem’s experimental method was extremely straightforward. He took established psychological protocols, such as affective priming and recall facilitation, and reversed the sequence, so that  the cause became the effect. For instance, he might show students a long list of words and ask them to remember as many as possible. Then, the students are told to type a selection of words which had been randomly selected from the same list. Here’s where things get really weird: the students were significantly better at recalling words that they would later type.


The power of Bem’s paper is cumulative. In total, he describes the results of nine different experiments, conducted on more than 1000 subjects. All of the experiments revealed slight yet statistically significant psi anomalies, with an average effect size of 0.21 across all experiments.

However, the real contribution of this paper isn’t even these statistically significant results. Instead, it’s Bem’s attempt to create rigorous, well-controlled tests of psi that can be replicated by independent investigators. Because here is the dirty secret of anomalous phenomena like telepathy and clairvoyance: They’ve been demonstrated dozens of times, often by reputable scientists. (Bem is an extremely well-respected psychologist, best known for his work on self-perception.) Why, then, do serious scientists dismiss the possibility of psi? Why do rational people assume that parapsychology is bullshit? Because these exciting results have consistently failed the test of replication.

According to a footnote on that article, the process of replication (or at least attempted replication) has already begun, and there are links to two sets of negative results.

Now, I’m no psychologist or statistician, but even so, I’m going to maintain a skeptical stance on “psi powers”. While I have vague theories that there’s more to the universe and our place in it than we yet understand, I think the notion of clairvoyance or “seeing the future” is – at best – a massive oversimplification of the sort of quantum weirdness that makes our brains work the way they do, or – at worst – what happens when unlikely but possible lucky streaks intrude themselves into the world of statistical probabilities. (That “slight yet significant” bit always sets my skeptic bell to ringing; how do we know how slight something has to be before it isn’t significant?)

But then you already knew I was I going to say that, didn’t you? 😉