Supplementary Materials.
Supplementary Table 1: Participant characteristics in experiment one. Values are Means (standard deviations).
Alcohol restraint (N=30) Neutral restraint (N=30)
Disinhibition (N=30)
F value (2,89)
p- Value
Gender (M : F)
13 : 17
14 : 16
14 : 16
-
-
Age
20.47 (2.49)
21.27 (3.05)
20.63 (2.40)
0.75
.43
Alcohol cons.
26.70 (14.25)
23.42 (8.56)
29.05 (14.04)
1.52
.23
AUDIT
14.33 (4.38)
14.07 (5.37)
15.57 (5.64)
0.72
.49
BIS Total
68.50 (8.87)
73.33 (10.90)
72.43 (10.47)
1.94
.15
BIS Motor
23.50 (4.35)
25.00 (4.85)
24.77 (5.13)
.85
.43
BIS Attention
18.03 (3.20)
19.17 (2.64)
19.10 (2.77)
1.46
.24
BIS Non Planning
26.97 (4.41)
29.17 (5.21)
28.57 (4.55)
1.73
.18
TRI CEP
25.57 (12.31)
24.37 (10.09)
25.20 (9.47)
0.99
.91
TRI CBC
18.13 (9.99)
16.57 (8.65)
15.63 (7.75)
0.06
.94
Alcohol cons. = average self-reported weekly alcohol consumption in UK units (1 UK unit = 10ml or 8g of pure alcohol); AUDIT = Alcohol Use Disorders Identification
Test; BIS = Barratt Impulsivity Scales; TRI = Temptation and Restraint Inventory, CEP = Cognitive and Emotional Preoccupation, CBC = Cognitive Behavioural Control.
Supplementary Table 2. Self-reported mood and alcohol craving before and after completion of the inhibitory control manipulations, in experiments one and two. Values are means (standard
deviations).
Pre-manipulation
Post-Manipulation
A. Experiment one
Alcohol restraint
Neutral restraint
Disinhibition
Alcohol restraint
Neutral restraint
Disinhibition
AAAQ Inclined
4.46 (1.89)
4.77 (1.60)
4.71 (1.92)
4.17 (2.08)
4.74 (1.78)
4.46 (2.15)
AAAQ Obsessed
0.98 (1.21)
0.80 (1.19)
0.79 (0.93)
0.81 (1.13)
0.98 (1.05)
1.05 (0.97)
AAAQ Resolved
1.15 (1.12)
0.80 (1.12)
1.10 (0.93)
0.92 (1.15)
0.85 (1.37)
1.27 (1.19)
BMIS Pleasant
9.93 (5.84)
8.13 (5.57)
7.73 (6.81)
8.80 (6.74)
6.90 (5.80)
6.23 (6.26)
BMIS Arousal
15.20 (4.08)
15.83 (3.75)
15.30 (2.83)
14.80 (3.47)
14.33 (4.29)
14.93 (3.73)
BMIS Negative
4.13 (2.86)
5.03 (2.72)
5.03 (2.81)
4.20 (2.37)
4.77 (2.33)
5.43 (3.00)
BMIS Positive
8.93 (3.69)
8.73 (3.35)
8.33 (3.33)
8.23 (4.15)
7.30 (4.27)
7.43 (3.34)
B. Experiment two
Alcohol
Neutral
Alcohol
Neutral
AAAQ Inclined
4.47 (1.75)
5.17 (4.14)
4.17 (1.92)
4.51 (1.90)
AAAQ Obsessed
1.05 (1.28)
1.20 (1.30)
1.08 (1.40)
1.25 (1.49)
AAAQ Resolved
1.24 (1.28)
1.45 (1.35)
0.90 (0.96)
1.40 (1.40)
BMIS Pleasant
8.63 (5.96)
9.13 (5.30)
5.73 (6.68)
9.03 (6.39)
BMIS Arousal
14.77 (4.31)
15.33 (4.66)
13.10 (4.20)
13.60 (4.09)
BMIS Negative
4.40 (2.95)
4.33 (2.86)
4.50 (3.04)
3.50 (2.36)
BMIS Positive
8.40 (3.57)
8.33 (3.82)
6.00 (4.13)
7.63 (4.38)
BMIS = Brief Mood Introspection Scale; AAAQ = Approach and Avoidance of Alcohol Questionnaire.
Supplementary Table 3: Participant characteristics in experiment two. Values are means (standard deviations).
Alcohol restraint(N=30)
Neutral restraint (N=30)
t- Value
p- Value
Gender (M : F)
13 : 17
15 : 15
-
-
Age
21.37 (3.32)
21.00 (2.75)
0.47
.64
Alcohol cons.
30.13 (15.62)
31.18 (23.72)
-0.20
.84
AUDIT
13.97 (5.37)
13.70 (4.26)
0.21
.83
BIS Total
70.03 (10.18)
67.53 (9.79)
0.97
.34
BIS Motor
23.40 (4.78)
23.20 (4.40)
0.17
.87
BIS Attention
18.73 (2.68)
18.37 (2.66)
0.53
.60
BIS Non Planning
27.90 (4.75)
25.97 (4.87)
1.56
.13
TRI CEP
25.70 (10.39)
23.63 (9.27)
0.81
.42
TRI CBC
15.37 (8.18)
16.17 (9.52)
-0.35
.73
Alcohol cons.= average self-reported weekly alcohol consumption in UK units (1 UK unit = 10ml or 8g of pure
alcohol); AUDIT = Alcohol Use Disorders Identification Test; BIS = Barratt Impulsivity Scales; TRI =
Temptation and Restraint Inventory, CEP = Cognitive and Emotional Preoccupation, CBC = Cognitive
Behavioural Control.
Supplementary analysis: Awareness of experimental contingencies.
Method
During the funnelled debriefing, participants were instructed to select from eight possible
options in order to complete the sentence ‘The computer task was designed to.....’. Response
options included ‘train me to inhibit to alcohol cues’ (correct response for participants in the
‘alcohol restraint’ groups), ‘train me to inhibit to neutral cues’ (correct response for
participants in the ‘neutral restraint’ groups), and ‘measure reaction times to the target
stimuli’ (correct response for participants in the ‘disinhibition’ group in experiment one).
There were five other response options which were not correct for any of the participants
(e.g. ‘train me to think more quickly’).
Results
Experiment one
Twenty five participants (27.7%) were aware of the purpose of the task (12 from the Alcohol
restraint group, eight from the Neutral restraint group and five from the Disinhibition group,
2 (2, 90) = 4.10, p = .12 ). When we removed data from these participants and repeated the
analyses, the group difference in ad-libitum alcohol consumption in the laboratory was still
significant (F(2,62) = 5.34, p<.01) with Bonferroni post hoc analysis showing significant
differences between Alcohol Restraint and Neutral Restraint groups (p<.05) and Alcohol
Restraint and Disinhibited (p<.05) groups. There was no significant difference between
Neutral Restraint and Disinhibited groups (p>.10). The group difference in self-reported
alcohol consumption at one-week follow-up was still non-significant (F(2,53)=0.61, p>.1).
Experiment two
Five participants (8.3%) were aware of the purpose of the task (two from the Alcohol
restraint group and three from the Neutral restraint group, 2 (1, N = 60) = 0.22, p = .64).
When we removed data from these participants and repeated the analyses, the group
difference in ad-libitum alcohol consumption in the laboratory was still non-significant
(t(53)= -1.13, p > .1).