Daryl Bem's Presentiment Experiments

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Re: Daryl Bem's Presentiment Experiments

#41  Postby Mr.Samsa » Oct 21, 2010 6:48 am

tnjrp wrote:Yep, there is always a chance of a "strange attractor" at work isn't there? In this case, Jaytee might be (might have been?) psychic even tho no compelling evidence was found.


Yeah the weird thing that I don't get about Sheldrake's analysis is that his graphs clearly show evidence that the dog significantly increased his "window approaching" behavior before the owner had been given the signal to come home, yet he counts this as supporting evidence...

tnjrp wrote:And in any case, there's some reason to believe Wiseman indeed did have a goatee at the time :mrgreen:


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Re: Daryl Bem's Presentiment Experiments

#42  Postby tnjrp » Oct 21, 2010 7:13 am

Mr.Samsa wrote:Yeah the weird thing that I don't get about Sheldrake's analysis is that his graphs clearly show evidence that the dog significantly increased his "window approaching" behavior before the owner had been given the signal to come home, yet he counts this as supporting evidence...
Well, that would show that the dog knew beforehand when the signal would be given, wouldn't it? It was supposed to be presentient after all, not clairvoyant, or so I gather. And the study says nothing about its intelligence... It might be psychic, but, like, really st00pid :tongue:
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Re: Daryl Bem's Presentiment Experiments

#43  Postby Mr.Samsa » Nov 02, 2010 11:55 am

Bem's paper has been criticised here - Why Psychologists Must Change the Way they Analyse Data: The Case of Psi. I don't necessarily agree with the author's criticism of Bem's "Bem Exploration Method" as I think they've misunderstood his approach, unfairly changing his angle from a valid scientific design to appear to be a more insidious case of a file drawer effect.

Besides that, I'm happy that they've basically just outlined all the problems I had with his paper - particulary the section on using a Bayesian hypothesis model to calculate conditional probabilities. Such an approach is vital in his research and I just can't understand why he didn't use it.

The criticism paper is a good paper though, well written. :cheers:
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Re: Daryl Bem's Presentiment Experiments

#44  Postby VK-machine » Nov 09, 2010 2:50 pm

Hearsayhas it that Bem has received more than 100 requests for material necessary to replicate his experiments. Poor sucker.

Anyone know of any parapsychologists throwing Bem under the bus?
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Re: Daryl Bem's Presentiment Experiments

#45  Postby jerome » Nov 12, 2010 12:10 pm

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Re: Daryl Bem's Presentiment Experiments

#46  Postby Mr.Samsa » Nov 13, 2010 2:35 am

Failure to replicate Experiment 8: http://papers.ssrn.com/sol3/papers.cfm? ... id=1699970

Abstract:
We replicated the procedure of Experiment 8 from Bem (2010), which had originally demonstrated retroactive facilitation of recall. We failed to replicate the result. The paper includes a description of our procedure and analysis as well as a brief discussion for some reasons why we obtained a different result than in the original paper.
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Re: Daryl Bem's Presentiment Experiments

#47  Postby jerome » Nov 13, 2010 1:19 pm

Yes, they ar enow trying again with a closer methodological match. I shall watch with interest. :)
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Re: Daryl Bem's Presentiment Experiments

#48  Postby jerome » Nov 15, 2010 1:47 am

Replication via online experiment here
http://consumerbehaviorlab.com/esp1_live/esp1_live.php
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Re: Daryl Bem's Presentiment Experiments

#49  Postby Ihavenofingerprints » Nov 18, 2010 12:46 pm

I just found this in the news. Maybe make a new thread for this new experiment?

http://www.news.com.au/technology/proof ... 5956004717
IF THE science is correct, there is probably not much point in reading the rest of this story. You should already know what's coming.
A psychologist in Britain has finished a study that provides the first scientific proof that psychic powers actually exist.
While some will claim the results of the study by Professor Daryl Bem could come down to chance, the mathematic probability of his findings being a statistical fluke are one in 74 billion.


I don't know what they are trying to claim from this experiment, every article on it is pretty bad and gives no source or decent information.

edit: I found a good website:http://www.periscopepost.com/2010/11/how-to-predict-the-future/

Here is the original paper: http://www.dbem.ws/FeelingFuture.pdf
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Re: Daryl Bem's Presentiment Experiments

#50  Postby my_wan » Nov 19, 2010 1:22 pm

Bem's experiments are exploratory. Thus they generally lack sample sizes needed for the multiple effects derived from it. In general, if you are testing a single effect, the sample size needed is much smaller than what's needed if you use the same dataset to test multiple effects. When the effects are open ended, like in an exploratory analysis, there's no clear way to define how big a sample size is needed to establish an effect. This is the underlying problem with Dem's paper.

However, Dem did set a new bar on the methodology, which should not be underestimated. It's been sorely lacking in the field in general. Dem should be commended on the quality of the methodology, even if more runs geared to more narrow effects tests are needed to establish evidence for those effects. Hopefully parapsychology researchers will take this quality to heart, and correctly address the sample size verses effect numbers being tested in follow ups.

Discussing every conceivable coincidence in a particular data set is pointless and proves nothing. Though exploratory analysis is very useful in deciding which effects might be best to do a more narrow study on, it's not the smoking gun in itself. Now let's see this excellent methodology applied to some 'specific' effect test. Then we'll have some real issues to discuss if they continue to come up positive.

I would even suggest triple blinding. That way a study contains its own meta-study, and should get you near a 100% success rate, no matter how small the effect is. So long as the sample segments are large enough to be detected to be over 50% by any tiny amount, no matter how tiny. To do this simply have each run of say 1000 (or however big a sample segment you *predefine*), and have say a 50 of these 1000 sample sets. Now each set of 1000 will be compared, and given a single + if even 1 more that 50% of the 1000 matches. So as long as the effect persist, then all 50 sets of 1000 should also result in a + label. If the range is anywhere near 50% for the *predefined* sets of sets, it's a bust for the effect at that sampling resolution. No matter what else might look out of randomness when you start after the fact redefining how to divide up the sample sets. Such after the fact analytical explorations by definition can't establish the reality of any effect found that way.
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Re: Daryl Bem's Presentiment Experiments

#51  Postby Hnau von Thulcandra » Nov 22, 2010 9:52 pm

Oh yay, I was going to start my own thread here but wisely searched first. This was announced in class by my own psychology professor a week or so past. Of course you people have all sorts of boring and plausible explanations, but I would dearly like this to be "real".
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Retroactive PSI events

#52  Postby chairman bill » Nov 25, 2010 11:33 am

From the BPS (British Psychological Society) Digest this morning,

6. Dramatic study shows participants are affected by psychological phenomena from the future
----------------------------------------

Perhaps there's something in the drinking water at Cornell University. A new study involving hundreds of Cornell undergrads has provided a dramatic demonstration of numerous 'retroactive' psi effects - that is, phenomena that are inexplicable according to current scientific knowledge (pdf).

Rather than having the students read each others' minds or wear sliced ping-pong balls over their eyes, Daryl Bem has taken the unusual, yet elegantly simple, approach of testing a raft of classic psychological phenomena, backwards.

Take priming - the effect whereby a subliminal (i.e. too fast for conscious detection) presentation of a word or concept speeds subsequent reaction times for recognition of a related stimulus. Bem turned this around by having participants categorise pictures as negative or positive and then presenting them subliminally with a negative or positive word. That is, the primes came afterwards. Students were quicker, by an average of 16.5ms, to categorise negative pictures as negative when they were followed by a negative subliminal word (e.g. 'threatening'), almost as if that word were acting as a prime working backwards in time.

If psi abilities have really evolved, it makes sense that they should confer survival advantages by helping us find mates and avoid danger. In another experiment Bem had dozens of undergrads guess which set of curtains in a pair on a computer screen was concealing an erotic picture. Participants were accurate on 53.1 per cent of trials, compared with the 50 per cent accuracy you'd expect if they were simply guessing. This accuracy was increased to 57 per cent among students who scored higher on a measure of thrill-seeking. By contrast, no such psi effects were observed for neutral stimuli.

In another experiment participants looked at successive pairs of neutral mirror images and chose their favourite - the left or right. After each pair, an unpleasant picture was flashed subliminally on one side or the other. You guessed it, participants tended to favour the mirror image on the side of the screen opposite to where an unpleasant picture was about to appear.

The examples keep coming. The mere exposure effect is when subliminal presentation of a particular object, word or symbol causes us to favour that target afterwards. Bem turned this backwards so that participants chose between pairs of negative pictures, and then just one of them was flashed subliminally several times. Female participants tended to favour the negative images that went on to be flashed subliminally, as if the mere exposure effect were working backwards through time.

This backward mere exposure effect didn't work for male undergrads, perhaps because the images weren't arousing enough, so Bem replicated the experiment using more extreme negative images and erotic images. This time a 'backwards' mere exposure effect was found with men for unpleasant images. For positive imagery, mere exposure traditionally has a negative effect, as the stimuli are made to become more boring. Bem showed this effect could also happen from the future. Presented with pairs of erotic images, male undergrads showed less favour for the images that went on to be flashed subliminally multiple times. It's as if the participants knew which images were going to become boring before they had.

Finally, we all know that practice improves learning. Bem tested students' memory for word lists and then had them engage in extensive practice (e.g. typing out) for some of the words but not others. His finding? That memory performance was superior for words that the students went on to practice afterwards - a kind of reverse learning effect whereby your memory is improved now based on study you do later.

These reverse effects seem bizarre but they are backed up by some rigorous methodology (but see failed replications and criticisms via the links at the bottom of this blog entry: http://tinyurl.com/34rmgyq). For example, Bem used two types of randomisation for the stimuli - one that's based on computer algorithms, which produce a kind of pseudo-randomisation in the sense that a given distribution of stimuli is decided in advance. And another form of randomisation based on hardware that produces true randomisation that unfolds over time as an experiment plays out. Also throughout his paper, Bem uses multiple forms of simple statistical test and he reports results for each, thus demonstrating that he hasn't simply cherry picked the approach that produces the right result. Across all nine experiments the mean effect size for the psi effects was 0.22 - this is small, but noteworthy given the nature of the results.

So what's going on? Bem doesn't proffer too many answers although he argues that his psi phenomena vary with subject variables, just like mainstream psychological effects do. For example, the phenomena were nearly always exaggerated in the more extravert, thrill-seeking participants. From a physics perspective, he believes the explanations may lie in quantum effects. 'Those who follow contemporary developments in modern physics ... will be aware that several features of quantum phenomena are themselves incompatible with our everyday conception of physical reality,' Bem argues. 'Many psi researchers see sufficiently compelling parallels between these phenomena and characteristics of psi to warrant considering them as potential candidates for theories of psi.'
_________________________________

Daryl Bem (2010). Feeling the future: Experimental evidence for anomalous retroactive influences on cognition and affect. Journal of Personality and Social Psychology. In Press: http://www.dbem.ws/FeelingFuture.pdf

Author weblink: http://dbem.ws/


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Re: Retroactive PSI events

#53  Postby katja z » Nov 25, 2010 1:12 pm

I think the nonsense I've just read dissuaded me from having clicked on this topic earlier.
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Re: Retroactive PSI events

#54  Postby Paul » Nov 25, 2010 1:42 pm

"Peter, I can see your house from here!"
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Re: Retroactive PSI events

#55  Postby tnjrp » Nov 26, 2010 6:39 am

chairman bill wrote:Question is, who knew I was going to post this?
And if anyone did, did anyone know it "before" you decided to post it or did you mess up with their causality when posting it? :shifty:
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Re: Daryl Bem's Presentiment Experiments

#56  Postby jerome » Dec 12, 2010 4:18 pm

Replication posted --

Batthyany, Alexander, Retrocausal Habituation and Induction of Boredom: A Successful Replication of Bem (2010; Studies 5 and 7) (November 27, 2010). Available at SSRN: http://ssrn.com/abstract=1715954

Full text available free from SSRN. (Download link for .pdf at top of page)


Abstract:
Bem (2010) reports evidence suggestive of unconscious retrocausal processes in human cognition. Bem’s findings appear to imply that under some circumstances, human subjects may display psychologically or physiologically meaningful reactions to future stimuli about whose occurrence they have no direct or indirect knowledge. This working paper describes a group replication attempt of Bem's (2010) studies 5 and 7, i.e. “time-reversed” affective habituation to highly arousing negative pictures and retrocausal induction of boredom/aversion to low arousing, mildly positive pictures (n=70). Evidence suggestive of a retrocausal influence of later stimulus display on subjects‘ preference ratings was found for affective habituation with high arousing negative stimuli; further, as in Bem’s study 7, retrocausal boredom induction was found for subjects high in boredom proneness.


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Re: Daryl Bem's Presentiment Experiments

#57  Postby jerome » Dec 12, 2010 4:54 pm

As I have already raised this on the JREF - Libet's initial speculations on volition and Readiness Potential will take on new light IF Bem is correct? In fact many things will suddenly change in our understanding of these matters?

http://en.wikipedia.org/wiki/Benjamin_L ... _potential
http://www.consciousentities.com/libet.htm

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Re: Daryl Bem's Presentiment Experiments

#58  Postby jerome » Dec 12, 2010 10:46 pm

Savva Child & Smith 2005 variant of Bem's study
http://edgehill.academia.edu/RobChild/P ... er_stimuli

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Re: Daryl Bem's Presentiment Experiments

#59  Postby jerome » Dec 12, 2010 10:52 pm

Two more - just abstracts --

JSPR 71.1 888 2007.


CAN A SLIDE-SHOW PRESENTIMENT EFFECT BE DISCOVERED IN BRAIN ELECTRICAL ACTIVITY ?
by Thilo Hinterberger, Petra Studer, Marco Jager, Colette Haverty-Stacke and Harald Walach

ABSTRACT
The presentation of pictures evokes clearly detectable responses in the electroencephalogram (EEG). Here, the question is addressed whether people show an anomalous pre-stimulus response prior to a sudden appearance of pictures. Therefore, twenty participants were exposed at randomised times to affective and non-affective pictures, and to checkerboard stimuli. In a non-parametric statistical analysis the one-second pre-stimulus epochs were compared with arbitrarily chosen non-exposed pre-stimulus epochs. In a second step, the contrasts between the pre-stimulus responses of different conditions were tested for significance. Checkerboard stimulation revealed no effect, whereas the picture stimuli resulted in a significant increase of the EEG activity. For affective pictures as well as for the difference between affective and neutral pictures, significant z-scores greater than z = 2.0 were found. A control condition with a covered monitor did not show such an effect. The delta band power was only decreased before presentation of pictures. The results support the possible existence of an abnormal presentiment effect. As it is not visible in the averaged EEG curves, this effect may not be time-locked to the stimulus and may be different for each participant. The non - significant results for neutral pictures and checkerboard stimuli suggest that emotional affectivity is important for a pre-stimulus effect in the EEG.


JSPR April 2009
Moderating Factors in Precognitive Habituation: The Roles of Situational Vigilance, Emotional Reactivity and Affect Regulation

In this experiment moderating factors of the so-called precognitive habituation effect were studied. The precognitive habituation effect refers to the apparent influence of later shown pictures or words on participants’ choice and preference ratings, which seem to be biased by habituation effects due to repeated display in the future, and so might be interpreted as an instance of precognition. In this study a number of modifications were introduced in the classic precognitive habituation protocol: (a) words and pictures were used as stimulus material, (b) a new individual difference was measured as a potential factor (affect regulation), and (c) subjects were primed into a reactive mindset in order to highlight the affective nature of the choice task. Only low-arousal positive and high-arousal negative stimuli were used. There was no significant main effect, but in accordance with previous results, subjects who scored high on emotional reactivity displayed a significant precognitive habituation effect, but only with high-arousal negative stimuli. Subjects high on affect regulation also showed a significant precognitive habituation effect for negative stimuli. The strongest effect was displayed by subjects who were high both on emotional reactivity and affect regulation.
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Re: Daryl Bem's Presentiment Experiments

#60  Postby jerome » Dec 12, 2010 11:09 pm

Just in case anyone actually interested in this stuff, Parker 2010 -- http://www.faqs.org/periodicals/201004/2090415421.html
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