1. •
Social Delay Discounting: How One’s Peers Impact Impulsive Choice in
Healthy Non-dependent Drinkers
E.R. Yalin, B.L. Stangl, J. Gilman, V.A. Ramchandani
Section on Human Psychopharmacology
National Institute on Alcohol Abuse and Alcoholism, Bethesda MD
INTRODUCTION RESULTS
SUMMARY AND CONCLUSIONS
METHODS
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Supported by the NIAAA Division of Intramural Clinical and Biological Research (Z1A AA000466).
Subject Demographics
MISS Associated with SDD Measures
E-mail address: elgin.yalin@nih.gov
NEO N-Impulsivity Associated with %SS
SDD Sex Differences
Impulsivity is a multi-faceted construct that reflects bias
towards immediate action without thoughtful consideration
for future consequences. Greater levels of impulsivity
have been associated with current alcohol use (Vuchinich
& Simpson, 1998) and can be an important predictor of
later alcohol abuse (Dick et al., 2010). Choice impulsivity
involves a tendency to select small, sooner rewards rather
than large, later rewards (Hamilton et al., 2015). People
with alcohol dependence devalue delayed rewards more
than those in the general population (Bickel & Marsch
2001). Social influence has been shown to increase
impulsive choices in healthy young adult drinkers (Gilman
et al., 2014). Decisions between delayed and non-delayed
rewards are susceptible to peer influence and can
demonstrate a vulnerability to future alcohol dependence.
This study is aimed to determine the strength of social
influence on impulsivity, inform early intervention efforts,
and potentially predict vulnerability to alcohol abuse with
personality traits.
SDD Task Seen by Participants
Sample
Characteristic
Total
(n = 20)
Males
(n = 7)
Females
(n= 13)
p value
Age (years) 25.4 ± 5.4 27.9 ± 8.7 24.0 ± 1.9 ns
Total Drinks in Past
90 Days 65.7 ± 34.5 66.9 ± 13.4 65.1 ± 9.8 ns
Drinking Days in
Past 90 Days 24.5 ± 12.2 22.1 ± 4.7 25.7 ± 3.4 ns
Drinks per Drinking
Day in Past 90 Days 2.7 ± 0.9 3.0 ± 0.3 2.6 ± 0.2 ns
Heavy Drinking days
in Past 90 Days* 4.6 ± 5.4 2.9 ± 2.0 5.5 ± 1.5 ns
*Heavy Drinking Day = 4 or more drinks for females and 5 or more drinks for males.
•Healthy male and female non-dependent drinkers
(n=20) ages 21-45 years old completed the study.
•Social Delay Discounting: A task to assess impulsivity
and susceptibility to peer influence through presentation
of small, sooner (SS) rewards and large, later (LL)
rewards. Peers’ faces and their choice are presented
during the task. Peers might both choose the impulsive
(SI) or nonimpulsive choice (S). Sometimes different
choices (D) are selected or their choice is not shown at
all (X).
•The calculated discount rate “k” and the %SS choices
were used as impulsivity measures.
•Impulsivity: A Delay Discounting Task (DDT) is used to
make sure the SDD is reliable (Bjork, Momenan, &
Hommer, 2009). Other questionnaires include the
Barratt Impulsiveness Scale (BIS), UPPS-P Impulsive
Behavior Scale, and the NEO Personality Inventory.
•Recent Drinking History: Timeline follow back (TLFB) 90
days drinking history (Sobell & Sobell, 1992) and the
Alcohol Use Disorder Identification Test (AUDIT).
•Personality: The Multidimensional Iowa Suggestibility
Scale (Kotov et al., 2004) (MISS) is used to determine
how influential participants are to each social condition.
•Laboratory Alcohol Consumption: A Computer-Assisted
Self-infusion of ethanol (CASE) session was completed
by each participant to quantify drinking in the lab setting.
M IS S T o ta l b y S e x
MISSTotalScore
0
5 0
1 0 0
1 5 0
2 0 0
2 5 0 F em ale
M ale
p = 0 .0 6 6
% S S C h o ic e s b y S e x
a n d In flu e n c e T y p e
S D D In flu e n c e T y p e
%SSChoices
S
C
o
n
d
itio
n
S
I
C
o
n
d
itio
n
X
C
o
n
d
itio
n
0
2 0
4 0
6 0
8 0
F em a le
M ale
p = 0 .1 2 3
L o g (K ) V a lu e s b y S e x
a n d In flu e n c e T y p e
S D D In flu e n c e T y p e
Log(K)Value
S
C
o
n
d
itio
n
S
I
C
o
n
d
itio
n
X
C
o
n
d
itio
n
-4
-3
-2
-1
0
F em a le
M ale
p = 0 .1 7 2
N Im p u ls iv ity a n d C h a n g e in % S S
C h o ic e s w ith Im p u ls iv e In flu e n c e
N E O N Im p u lsiv ity S c o re
%SSChoices
3 0 4 0 5 0 6 0 7 0
-1 0
0
1 0
% S S S I-X
p = 0 .0 2 4
P e e r C o n fo rm ity S c o re a n d
L o g (K ) V a lu e s *
M IS S P e e r C o n fo rm ity S c o re
Log(K)Value
2 0 3 0 4 0 5 0 6 0
-4
-3
-2
-1
0 L o g (S )
L o g (S I)
L o g (X )
p = 0 .0 3 3
*n o s ig n ific a n t d iffe re n c e b e tw e e n e a c h c o n d itio n
M IS S T o ta l a n d % S S C h o ic e s *
M IS S T o ta l S c o re
%SSChoices
1 0 0 1 5 0 2 0 0 2 5 0
0
2 0
4 0
6 0
8 0
1 0 0
% S S S
% S S S I
% S S X
p = 0 .0 4 2
*n o s ig n ific a n t d iffe re n c e b e tw e e n e a c h c o n d itio n
P e e r C o n fo rm ity b y S e x
MISSPeerConformityScore
0
2 0
4 0
6 0
Fem ale
M ale
p = 0 .2 4 0
Associations Between Impulsivity and Personality
N Im p u ls iv ity a n d C h a n g e in % S S
C h o ic e s w ith N o n im p u ls iv e In flu e n c e
N E O N Im p u lsiv ity S c o re
%SSChoices
3 0 4 0 5 0 6 0 7 0
-1 0
-5
0
5
1 0
1 5
% S S S -X
p = 0 .7 5 1
Delay Discounting Schematic*
*(De Wit, Addiction Biology, 2008)
• Underlying participant discount rates (log(k) value)
were not affected by peer influence, but the
percentage of SS choices was higher when both
peers favored the impulsive reward.
• An overall negative association was found with %SS
choices or discount rate and MISS suggestibility
measures, which refuted expectations.
• Impulsive peers increased impulsive (SS) choices in
individuals that scored high on the self-report NEO N-
Impulsivity measure, while nonimpulsive peers did not
have a strong effect.
• The neuroticism and suggestibility measures were
strongly correlated perhaps due to self-consciousness
or anxiety of social consequences.
• The relationship between SDD and drinking
measures (AUDIT, TLFB, CASE) did not produce
significant findings most likely due to the small
sample size and relatively low range of drinking
history in the sample (data not shown).
• An ANOVA of UPPSP Premeditation with the SDD
values (%SS, change in %SS, log(k), k value)
showed significant within subject effects across all
measures (data not shown) indicating condition
impact and a future research direction.
• The findings of this study are preliminary and would
need to be replicated in a larger sample with a wider
range of drinking histories.
M IS S T o ta l a n d N E O N F a c to r
M IS S S u g g e s tib ility T o ta l
NFactorTotal
1 0 0 1 5 0 2 0 0 2 5 0
2 0
3 0
4 0
5 0
6 0
r
2
= 0 .7 3 5
p < 0 .0 0 1
M IS S P e e r C o n fo rm ity a n d N E O N fa c to r
M IS S P e e r C o n fo rm ity S c o re
NFactorTotal
2 0 3 0 4 0 5 0 6 0
2 0
3 0
4 0
5 0
6 0
r
2
= 0 .6 2 2
p = 0 .0 0 4
REFERENCES
•Bickel WK et al. (2001) Toward a Behavioral Economic Understanding of Drug Dependence: Delay Discounting Processes. Addiction 96: 73-86.
•Bjork JM et al. (2009) Delay Discounting Correlates with Proportional Lateral Frontal Cortex Volumes. Biol Psychiatry, 65(8), 710-713.
•Dick DM et al. (2010) Understanding the Construct of Impulsivity and its relationship to alcohol use disorders. Addict Biol 2:217-226.
•Gilman JM et al. (2014) Impulsive Social Influence Increases Impulsive Choices on a Temporal Discounting Task in Young Adults. PLoS ONE 9:7.
•Hamilton KR et al. (2015) “Choice Impulsivity: Definitions, Measurement Issues, and Clinical Implications.” Personality disorders 6:182–198.
•Kirby KN et al. (1996) Delay-discounting Probabilistic Rewards: Rates Decrease as Amounts Increase. Psychonomic Bulletin Review 3:100-104.
•Kotov RI et al. (2004) Multidimensional Iowa Suggestibility Scale (MISS) Brief Manual. Stoneybrook Medicine Website.
•Sobell LC et al. (1996)The Reliability of the Alcohol Timeline Followback when Administered by Telephone and by Computer. Drug Alcohol
Depend 1:49-54.
•Vuchinich RE et al. (1998) Hyperbolic Temporal Discounting in Social Drinkers and Problem Drinkers. Exp Clin Psychopharmacol 6: 292-305.
• %SS: percentage of
impulsive (small,
sooner) choices made
by each participant
• Log(K): log
transformed
discounting rate under
each condition
• S Condition: both
peers choose the
nonimpulsive reward
(large, later)
• SI Condition: both
peers choose the
impulsive reward
(small, sooner)
• X Condition: the
choices of the peers
are not shown to the
participant (control)
The NEO Neuroticism Impulsivity scores were analyzed with the change in percentage of
impulsive choices through a multivariate ANOVA with SPSS software. A positive interaction was
found with the impulsive minus the control influence, but there was no significance with the
nonimpulsive minus control influence.
Measures from the MISS questionnaire were correlated through SPSS software with the NEO
Neuroticism Total score. Both suggestibility total and the peer conformity domain had a significant
relationship with the total neuroticism score.