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condition. The other half performed the task first in hypnosis and then,
after a 5-minute break, in the nonhypnotized condition. Counterbalanc-
ing of testing order was systematic across all experimental groups
(high versus low susceptible by task instructions).
The hypnosis portion of the session consisted of the eye-closure
induction, hand-lowering, hypnotic-dream, and age-regression items
from the SHSS:C. The Stroop task was administered after the age-
regression item.
Participants were randomly allocated to one of five independent
instruction conditions for performing the Stroop task. These conditions
were termed: rehearsal, no-strategy, effortful concentration, relaxation,
and no-instruction.
Instructions (and number of participants) for each of these five
conditions were as follows:
Rehearsal
. When you see the box-shaped instruction for color-naming,
repeat the instruction ‘‘color’’ over to yourself, in your mind, to help you
prepare for naming the actual color when it appears on the screen.
Likewise, when you see the instruction ‘‘word’’ appear on the screen,
repeat ‘‘word’’ over to yourself, in your mind, to help you prepare for
naming the actual word when it appears on the screen. [
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No-strategy
. Don’t try to prepare in any special way when you see the
instructions for color-naming or word-naming appear on the screen.
When you see the actual word appear on the screen just let your response
happen spontaneously, by itself, without doing anything in particular to
make it happen. [
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26]
Effortful concentration
. I want you to stay fresh and alert. Concentrate on
the task. Don’t let your attention wander or be distracted in any way. Keep
your mind on what you are doing. Try as hard as you can. [
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28]
Relaxation
. Just relax and don’t be tense. Don’t make things hard for
yourself. If your mind wanders away, don’t let that worry you; just bring
your attention back to what you are doing. [
n
¼
28]
No instruction
. No additional instructions were given to participants in this
condition. [
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24]
The particular instructions for participants’ assigned condition were
read aloud to them by the experimenter immediately prior to each time
the Stroop task was performed, whether in the hypnotized or non-
hypnotized condition. There were an equal number of high and low
susceptible participants in all conditions.
After the completion of both hypnotized and nonhypnotized phases
of testing, participants received a brief but structured series of post-
experimental inquiry questions. The experimenter read out a brief
description of three strategies (rehearsal, experiential, positional) to
each participant and asked them to rate how frequently they had used
each strategy. Rehearsal was described as mentally rehearsing the
instruction of ‘‘word’’ or ‘‘color’’ as soon as participants receive
238
GRAHAM A. JAMIESON
AND
PETER W. SHEEHAN
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