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PAMELA SADLER AND ERIK Z. WOODY
identified for the heart-rate data started 2 seconds after the animal was
mentioned. Each imagery trial was preceded by an approximately 2-
minute baseline period that was similar to the initial baseline period,
during which the participant was asked to sit quietly and to think of
nothing in particular. The last minute of each of these preimagery peri-
ods was used as the baseline in the heart-rate data analyses.
After each imagery trial, participants were asked to describe the
imagined scene and to verbally rate the preceding imagery trial for
four important, subjectively experienced qualities (Glisky, Tataryn, &
Kihlstrom, 1995): vividness, absorption, effort, and control. Ratings
were all made on seven-point Likert scales and the endpoints were
described to participants, allowing them to remain with their eyes
closed during this entire reporting period. They were asked to rate
how vivid the image was, where 1 represented
no image present, only
thinking about it
and 7 represented
a perfectly clear and vivid image just
like an actual experience
. They also rated how absorbed or involved they
felt in the image, where 1 represented
many distractions, lost contact with
the scene much of the time
and 7 represented
highly absorbed in the image
and always involved with no extraneous thoughts
. They rated how much
effort it took to maintain the image on a scale where 1 represented
little
effort
and 7 represented
much effort
. They also rated how much control
they felt they had over the image, where 1 represented
little control, the
image seemed to happen on its own
and 7 represented
a high degree of con-
trol, the image was planned throughout
.
Upon completion of the six imagery trials, the participant was
aroused from hypnosis and debriefed. The entire experiment took
about 75 minutes for each participant to complete.
R
ESULTS
Subjective Experience
We first analyzed the subjective ratings to examine the nature of the
subjective experience of hypnotic imagery. There were four subjective-
experience measures: vividness, absorption, effort, and control. Prelimi-
nary analyses showed that the order of the two types of suggestion
wording had no significant effects, with one minor and uninteresting
exception; therefore, order was omitted from the statistical model. How-
ever, preliminary analyses also indicated that the effect of suggestion
wording tended to interact with gender, so gender was included as a
factor in the model. For each of the subjective ratings then, we per-
formed a GLM (general linear model) with the within-subject variable of
suggestion wording (effortless vs. effortful) and the between-subject
variables of hypnotizability (low vs. high) and gender (female vs. male).
The analysis of vividness yielded a significant main effect for
hypnotizability,
F
(1, 44) = 9.53,
p
< .01,
h
2
= .18. As hypothesized, the
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