快猫短视频

Yes we can, according to a controversial new paper by leading social psychologist Daryl Bem. He tells Peter Aldhous how his hobby of stage magic led to a quest to bring parapsychology into the scientific mainstream

What does your show?

There are several alleged effects that we call 鈥減si鈥�, known popularly as extrasensory perception (ESP). Precognition 鈥� the perception of future events 鈥� is one of them. I took effects that all psychologists believe in and I reversed them in time. For example, if you present people with a set of words on a computer screen, then randomly select half of those words to give them practice by typing them, they will remember the words they practised better when given a memory test. In this case I simply reversed the sequence so that the memory test came before the practice.

And you still saw the effect?

Yes. It鈥檚 much smaller than when the experiments are run in the normal sequence, but people don鈥檛 realise how small many effects are that are very important. Everyone believes that taking a baby aspirin daily helps prevent heart attacks, but that effect is actually smaller than what I saw in my psi experiments.

The suggestion that information can flow backwards in time defies our understanding of reality, so how have people reacted to the paper?

Psi researchers are delighted that this is in a mainstream journal. Most of my fellow psychologists are doubtful about the effects. Reactions from the public can be extreme. Some tell me about their personal experiences with precognition. One email described my research as pseudoscience because it violates causality, and similar things appear in the comment sections of blogs.

How do you respond to scientists who reject the idea of precognition because there is no mechanism to explain how it could work?

The absence of a theory or a mechanism for any effect is certainly a reason to demand extraordinary evidence. But if you look at the history of science, many phenomena started out without a theory. Faraday didn鈥檛 have a theory when he started observing electricity and magnetism. Quantum mechanics doesn鈥檛 have a mechanism for physical reality.

What reaction are you expecting from sceptics?

When writing the paper, I tried to cover my ass in every possible way against critiques. My guess is that something probably will appear in Skeptical Inquirer magazine, and one of the things they can say is that we have to wait until replications occur. I totally agree with that.

In your paper you discuss the danger of results being subtly biased by the experimenter. Is this likely to be a big problem?

Experimenters鈥� expectations can affect even regular psychology experiments. My approach to this was to minimise the role of the experimenter and let the computer program do most of the work.

How tough was it to get this work accepted for publication?

It was actually no more difficult than with most of my papers. It鈥檚 partly because of my own obsessive-compulsive disorder 鈥� going over every paper as carefully as I can before I submit it. This went to four different reviewers, which is more than usual. But I was able to handle the objections that they had.

So how did one of the world鈥檚 leading social psychologists get involved in parapsychology?

I had an amateur stage career doing the kind of magic where you disguise a trick to look like a demonstration of ESP 鈥� it鈥檚 called 鈥渕entalism鈥�. The heard about this and asked me to perform at their convention in 1985. They wanted to see some of my techniques in action so that they could be on guard against someone like that.

Are you able to reveal these techniques?

They鈥檙e well known to magicians. I could reveal them but then I鈥檇 have to kill you!

How did your interest in psi grow?

I was already in contact with one person in the audience, , who was setting up a laboratory in Princeton, New Jersey. He had asked me to look at his set-up to make sure it was cheat-proof. These were the telepathy experiments known as the ganzfeld technique, in which volunteers try to receive messages while placed in a situation of mild sensory deprivation in a room distant from the sender. I said to him, 鈥淚f you get positive results with this technique I am willing to try and get these brought to the attention of mainstream psychology.鈥�

Honorton published the experiments in a parapsychology journal. Then he and I did a meta-analysis of the results and in the Psychological Bulletin. Sadly, Honorton died from a heart attack nine days before the paper was accepted.

Why didn鈥檛 that get mainstream psychologists interested?

Part of that is just practical. Everyone is involved in their own work, and doing experiments is hard. That is why this time I decided to be as simple and as transparent as possible, and use experiments that were familiar to psychologists. I wanted to interest people in trying to repeat my work because replication is the gold standard of whether you should believe something.

鈥淩eplication is the gold standard of whether you should believe something鈥�

James 鈥淭he Amazing鈥� Randi, a fellow magician and prominent sceptic, has put up for anyone who can provide evidence of the paranormal. Are you tempted to enter?

No. He controls the entire process and he has never been totally clear as to what level of probability he would accept. He also insists on having all the rights to reporting what happened and that鈥檚 not how we as scientists progress.

You have described yourself as a maverick. In what other ways have you followed an idiosyncratic path?

I trained in physics, but I came of age in the early 1960s and I was fascinated by the change in public opinion towards desegregation in the American South. That led me to switch to social psychology. It had always been the general wisdom you cannot change people鈥檚 behaviour until you first change their hearts and minds. Yet when we looked at attitude changes in the South we found the reverse was true 鈥� that changing people鈥檚 behaviour through judicial or legislative action actually changed their attitudes fairly rapidly thereafter.

Later you got interested in the origins of sexual orientation. Tell us about that.

The Freudian view that sexual orientation develops from the child-rearing environment just wasn鈥檛 supported by evidence. But I nevertheless was suspicious of the notion that it is directly coded in the genes. I gradually developed the . This argues that because of their temperament, some children are attracted to activities typical of the same gender, while others prefer those commonly enjoyed by the other gender. As adults, people become sexually attracted to the gender which they see as different.

You were married for nearly 30 years, and now you identify yourself as a gay man. Did your personal experiences inform this theory?

Any psychological theory is often a theory of oneself. In fact my wife and I never divorced. Shortly after we met, I said, 鈥淭hree things you should know about me: I鈥檓 from Colorado, I鈥檓 an amateur magician, and I鈥檓 predominantly homoerotic.鈥� Her response was, 鈥淵ou know, I don鈥檛 think I鈥檝e ever known anyone from Colorado before.鈥� I knew I was homoerotic but I fell in love with her. We had a monogamous marriage and I just sort of put that aside.

What comes next? More experiments on psi, or do you have other plans?

I don鈥檛 know what鈥檚 going to come along. Right now I鈥檓 swamped with requests for computer source code and raw data from my experiments. In due course I will make the raw data available, once I have removed all identifying information about the subjects.

I鈥檇 like to do some experiments in a real-life situation. I hope to do an experiment with a class where they are given a multiple-choice exam. Immediately afterwards we will ask them to be in an experiment and we will give practice on half the questions, and then go back and see whether they did better on those.