A prominent psychological journal is expected to make history later this year when it publishes what is believed to be the first scientific paper arguing that humans can predict the future.
But that doesn't mean you should rush out to the betting parlors just yet: While the research (PDF) shows statistically significant numbers to prove that people are capable of some degree of "precognition," the effect has to be repeated by other researchers many times before it becomes accepted scientific knowledge.
And not even the researcher who carried out the experiment can explain how the future can affect past events.
Researchers who have reviewed Cornell University psychologist Daryl Bem's paper say it's scientifically sound, reports New Scientist.
"My personal view is that this is ridiculous and can't be true," says Joachim Krueger of Brown University in Providence, Rhode Island, who has blogged about the work on the Psychology Today website. "Going after the methodology and the experimental design is the first line of attack. But frankly, I didn't see anything. Everything seemed to be in good order."
"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," New Scientist reports. "Spookily, the students were better at recalling words that they would later type."
To create experiments that a skeptical scientific community would believe, Bem decided against setting up questionable "tests" of soothsaying, and instead "reversed" existing psychological tests, running test subjects through them backwards. Science Daily reports:
[M]any studies have found that people are slower to decide a picture is pleasant if they've seen a negative word right before looking at the picture. So someone reading the word "ugly" before seeing a picture of a lovely sunset will be slower to call the picture pretty than someone who just read the word "beautiful." This phenomenon is called "priming."
Bem reversed that experiment, presenting the picture, then the response, and finally the priming word. And what do you know? He found something that looked very much like retroactive priming, in which people who would eventually be shown negative words were slower to say positive things about the pictures.
In another test, subjects were told they were about to see an erotic image in one of two poses, and asked to predict the pose. Subjects predicted the result 53.1 percent of the time. That may seem like little more than the 50 percent one would expect in a random sample, but as New Scientist notes, "well-established phenomena such as the ability of low-dose aspirin to prevent heart attacks are based on similarly small effects."
Bem told New Scientist that he took eight years to conduct the experiments and used more than 1,000 test subjects to gather enough evidence to publish his report.
"I purposely waited until I thought there was a critical mass that wasn't a statistical fluke," he said.
All the same, criticisms are inevitably beginning to mount. New Scientist reports:
One failed attempt at replication has already been posted online. In this study, Jeff Galak of Carnegie Mellon University in Pittsburgh, Pennsylvania, and Leif Nelson of the University of California, Berkeley, employed an online panel called Consumer Behavior Lab in an effort to repeat Bem's findings on the recall of words.
Bem argues that online surveys are inconclusive, because it's impossible to know whether volunteers have paid sufficient attention to the task. Galak concedes that this is a limitation of the initial study, but says he is now planning a follow-up involving student volunteers that will more closely repeat the design of Bem's word-recall experiment.
Bem's paper is scheduled to appear in an upcoming issue of the Journal of Personality and Social Psychology.