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For the previously designated experiential strategy, a significant
main effect was obtained for hypnosis,
F
(1, 122)
¼
88.30,
p
<
.01. Note
the magnitude of the
F
ratio. Table 3 shows that (unlike the rehearsal
and positional strategies) the use of the experiential strategy is greater
in the hypnotized than the nonhypnotized condition. A significant
effect was also found for susceptibility,
F
(1, 122)
¼
8.87,
p
<
.01. Table 5
shows that it was high susceptibles who demonstrated significantly
higher experiential strategy use than low susceptibles. Both of these
main effects are tempered by a significant interaction effect between
hypnosis and susceptibility,
F
(1, 122)
¼
9.81,
p
<
.01. The nature of the
interaction is made clear by contrasting the effect of susceptibility in the
hypnotized and nonhypnotized conditions.
There were significant differences between high and low suscepti-
bles in the hypnotized condition,
F
(1, 122)
¼
13.56,
p
<
.01. Highs re-
ported significantly greater levels of the experiential set in hypnosis
than did lows (see Table 5). However, the difference between high and
low susceptibles in the nonhypnotized condition was not significant.
As with the rehearsal strategy, there was no significant effect for
instructional condition on experiential ratings. Finally, for the posi-
tional strategy (as for the rehearsal strategy but opposite to the experi-
ential strategy), hypnosis was found to significantly decrease the
frequency of the strategies use,
F
(1, 122)
¼
17.25,
p
<
.01.
D
ISCUSSION
Objective criteria of Stroop-task performance were utilized to index
the operation of frontally mediated SAS control processes as proposed
in the neuropsychological literature. These neuropsychological pro-
cesses have been argued by Woody and Bowers (1994) to be critically
involved in the changes in the experiences that accompanies hypnosis.
Time-outs were used to measure lapses of attention (Van Zomeren &
Brouwer, 1994). Stroop color-naming reaction times were utilized to
measure suppressing attention (Stuss et al
.
, 1995). Time-outs were
Table 5
Mean Experiential Strategy Use by High and Low Susceptibles in Hypnotized and
Nonhypnotized Conditions
Hypnosis Condition
Susceptibility
High
Low
Hypnotized
3.17 (1.27)
2.38 (1.16)
Nonhypnotized
2.11 (1.14)
1.85 (0.93)
Column Totals
2.63 (1.32)
2.11 (1.08)
242
GRAHAM A. JAMIESON
AND
PETER W. SHEEHAN
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