impulsivity and cognitive distortions in …...‘close only counts in horseshoes and hand...
TRANSCRIPT
Impulsivity and Cognitive Distortions in Pathological Gambling
Dr Luke Clark
Department of Experimental Psychology
University of Cambridge, U.K.
The Psychology of Gambling
1. How do we explain the prevalence of gambling if people understand that ‘the house always wins’?
2. How does gamble become dysfunctional (addictive?) in a minority?
Cognitive distortions during
gambling
Brain mechanisms of decision-making and
reward processing
Emotional / physiological
responses in the body
The Cognitive Approach to Gambling
• Gamblers experience distorted processing of probability and randomness, such that they over-estimate their chances of winning
• Distortions elevated in problem gamblers
0
10
20
30
40
50
60
70
80
Gamblers Controls
Tota
l Sco
re
Gambling-Related Cognitions Scale
• Two basic types: 1) Sequential predictions based
on independence of turns 2) Mistaken appraisals of skill
due to perceived personal control
Clark (2010 Proc Roy Soc B), Michalczuk et al (2011)
The ‘Gambler’s Fallacy’ in Simulated Roulette
Simple task: • Guess RED or BLACK • Then, rate your
confidence
Black, Black, Black, Black “RED!” (i.e. negative recency)
Studer & Clark (in prep)
Choose red after Choose red after
The ‘Gambler’s Fallacy’ in Simulated Roulette
20
25
30
35
40
45
50
1 2 3 4 5
% s
ame
as p
revi
ous
outc
ome
Consecutive Reds / Blacks
Confidence after Loss Loss Confidence after Loss Loss Loss Loss
25
30
35
40
45
50
Short (1,2) Long (4,5) %
Cho
ice
of P
revi
ous
Outcome Run Length
-0.1
0
0.1
0.2
0.3
0.4
0.5
Short (1,2) Long (4,5)
Z(Co
nfid
ence
Rat
ing)
Losing Streak
Near-Misses
02
468
10
1214
15% 30% 45%
Near-Miss Frequency
Tria
ls in
Ext
inct
ion
“A special kind of failure to reach a goal, one that comes close to being successful” (Reid 1986)
Kassinove & Schare 2001
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
NearMiss FullMiss
Z s
core
of
rati
ng
"Continue to play?" "Pleased with outcome?"
Subjective Differences between Near-Misses and Full-Misses
Clark et al (2009 Neuron)
Arousal Responses to Wins and Near-Misses
-0.005
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
1 2 3 4 5 6 SCR
Cha
nge
from
Bas
elin
e (lo
g +
1)
Time post-outcome (2s bins)
Participant - WINS
All Non-Wins
-0.004
-0.002
0
0.002
0.004
0.006
0.008
0.01
0.012
1 2 3 4 5 6
SCR
Cha
nge
from
Bas
elin
e (lo
g +
1)
Time post-outcome (2s bins)
Participant - NEAR
Participant - FULL
Clark et al (2011 Journal of Gambling Studies)
fMRI Responses to Wins and Near-Misses
P<.05 FWE Dopaminergic
Midbrain Anterior
Insula Ventral Striatum mPFC
WINNING OUTCOMES minus ALL NON-WIN OUTCOMES
NEAR-MISS OUTCOMES minus FULL-MISS OUTCOMES
A
B
P<.001 uncorr Clark et al (2009 Neuron)
Gambling Severity predicts Near-Miss Activity in Midbrain
-1
-0.5
0
0.5
1
1.5
0 5 10 15 20
Per
cen
t Si
gnal
Ch
ange
SOGS
re-smoothed at 4mm
Chase & Clark (2010 J Neurosci)
‘Close only counts in horseshoes and hand grenades’
Horseshoes
Game of skill
Near-misses provide indication of skill acquisition, and thus likelihood of future success
Should be valued by brain reward system
Fruit machine
Game of chance
Near-misses provide no indication of future success
Should be ignored by brain
Griffiths (1993), Reid (1986)
• Gambling distortions can be elicited in healthy individuals in a laboratory environment (Gambler’s Fallacy, effects of near-misses)
• Near-miss outcomes are experienced as unpleasant but invigorate gambling behaviour
• Wins and near-misses are associated with phasic changes in peripheral arousal
• At a neural level, near-misses trigger anomalous activation in components of the brain reward system: VS, insula, vmPFC.
• The size of these near-miss responses predicts susceptibility to gambling distortions in healthy volunteers (insula) and severity of gambling involvement in regular gamblers (midbrain)
• No evidence for changes in (baseline) dopamine D2 receptors in PG, but correlations with impulsivity
Conclusions
Acknowledgements University of Cambridge
Andrew Lawrence
Rosanna Michalczuk
Henry Chase
Mike Aitken
Barbara Sahakian
Trevor Robbins
Barney Dunn (MRC CBU)
Funding support:
Medical Research Council
MRC – Wellcome Trust Behavioural and Clinical Neuroscience Institute
Economic and Social Research Council
Responsibility in Gambling Trust (now RGF)
Imperial College, London
Henrietta Bowden-Jones
Paul Stokes
Anne Lingford-Hughes
Kit Wu
Robert Rogers (Oxford)
Antonio Verdejo (U Granada)