All this having been said, I believe that what David said:
Research suggests that subliminal perception does
influence behavior (e.g., mere exposure effect and sublimal/masked
priming effects), as well as emotion (e.g., mere exposure to stimuli
increases one's mood).
is an accurate statement. Unfortunately, I don't have any refs handy :(
If I can make time I'll dig them up later this week.
Annette
Quoting Jim Clark <[EMAIL PROTECTED]>:
Hi
I think this paradigm is susceptible to a statistical artifact that I
have noticed in some other parapsychological experiments (Schwartz's
work comes to mind). The researchers essentially select distinct
conditions, defined in part by subjects' responses (an important
point!), and then determine whether the observed hit rate in that
condition differs from 50%. But the chance value may not be 50% if
subjects demonstrate any consistent preferences in making their
responses.
I can illustrate with hypothetical data for the paradigm in the linked
document. If I'm understanding correctly, the paradigm is essentially
that subjects indicate a preference for one of two pictures, and then
one of two pictures is randomly chosen for subliminal presentation. For
certain types of trial (e.g., unpleasant items), the preferred item has
a probability greater than .5 of being the item later selected for
subliminal presentation.
But .5 is only the proper comparison if subjects have an equal
probability of picking the different types of pictures. If they have a
preference for one type of picture over the other types, then the chance
probability of a match is greater than .5.
Suppose there were 200 trials in an experiment, with 100 negative and
100 positive pictures. And suppose that on half of the negative trials
(50 of 100), the negative picture is selected for subsequent
presentation. If subjects choose negative stimuli 50% of the time, then
the number of expected matches is .5 x 50 = 25, which gives an expected
probability for this cell of 25/50 = 50%. But if subjects choose the
negative stimulus more than 50% of the time, then the expected
probability changes. For example, if subjects choose the negative
stimulus 60% of the time, then the expected number of matches is .6 x 50
= 30, which gives an expected probability for this cell of 30/50 = 60%,
not the 50% against which researchers are wrongly comparing the observed
proportion of hits.
I could not find anything in this article to indicate what the baseline
choices of the different kinds of stimuli were, so this remains
hypothetical. But one should be extremely cautious about .5 being the
chance level anytime outcomes are defined partly by participants'
responses.
It is unfortunate that someone of Bem's stature is giving credence to
this nonsense. It is scant comfort to remember that Newton also
believed in astrology (I believe), inasmuch as astrology may now be a
thing of the past if he had not (unlikely, of course, but one can only
hope!).
Jim
James M. Clark
Professor of Psychology
204-786-9757
204-774-4134 Fax
[EMAIL PROTECTED]
[EMAIL PROTECTED] 14-Nov-05 3:40:09 PM >>>
A leading psychologist publishing in at least one leading journal
(Psych Bull), offering his program to anyone interested. I can't say
I'm convinced, but he's pretty darn convincing. Now, I'm off to buy a
lottery ticket. Tomorrow after the numbers are announced, I'm going to
present them to myself subliminally.
________________________________
From: Rick Stevens [mailto:[EMAIL PROTECTED]
Sent: Mon 11/14/2005 4:32 PM
To: Teaching in the Psychological Sciences
Subject: Re: student's question
Cancel that suggestion. I just put 'precognitive habituation' into
Google and it is Daryl Bem that I found first.
http://www.dbem.ws/Precognitive%20Habituation.pdf
I haven't read the whole thing but it says that anyone with a computer
and a stat program can reproduce it. I'll be a millionaire in no time.
Rick Stevens wrote:
Burns, Daniel wrote:
Research suggests that subliminal perception does
influence behavior (e.g., mere exposure effect and sublimal/masked
priming effects), as well as emotion (e.g., mere exposure to stimuli
increases one's mood). In fact, recent research out of Cornell suggests
that stimuli presented in the future actually affect your behavior now
(e.g., subliminal precognition).
I think that we have a candidate for the James Randi million
dollar prize. Send those people to Randi.org and have them sign up.
--
__ Dr. Rick Stevens
__ Psychology Department
__ University of Louisiana @ Monroe
__ [EMAIL PROTECTED]
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Annette Kujawski Taylor, Ph. D.
Department of Psychology
University of San Diego
5998 Alcala Park
San Diego, CA 92110
[EMAIL PROTECTED]
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