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@ Decision Neuroscience Scott Huettel, Duke University
The Neural Representation of Decision-Making under Uncertainty
Scott Huettel
Psychology & NeuroscienceDuke University
@ Decision Neuroscience Scott Huettel, Duke University
“…there are known knowns; there are things we know we know.
We also know there are known unknowns; that is to say we know there are some things we
do not know.
But there are also unknown unknowns -- the ones we don't know we don't know.”
- Rumsfeld (2003, in press)
@ Decision Neuroscience Scott Huettel, Duke University
“To preserve the distinction… between the measurable uncertainty and an unmeasurable one we may use the term
‘risk’ to designate the former and the term ‘uncertainty’ for the latter. …
It is this [type of] uncertainty which has been neglected in economic theory, and which we propose to put in its rightful
place.”
F. H. Knight (1921) Risk, Uncertainty, & Profit
@ Decision Neuroscience Scott Huettel, Duke University
Outline of the Talk
• Uncertainty defined
• Case study: Ambiguity– Contributions of lateral prefrontal, parietal
cortex?– Contributions of orbitofrontal cortex, amygdala?
• Discussion: What should neuroscience seek?
@ Decision Neuroscience Scott Huettel, Duke University
“Information occurs only if there exists some a priori uncertainty, and the amount of information is determined by the amount of the uncertainty – or, more exactly, it is determined by the amount by which the uncertainty has been reduced.”
- Garner (1962). Uncertainty and Structure as Psychological Concepts, p. 3.
Wendell “Tex” Garner
@ Decision Neuroscience Scott Huettel, Duke University
@ Decision Neuroscience Scott Huettel, Duke University
LPFC
Huettel, Mack, & McCarthy (2002) Nature Neuroscience
-0.025%
0.000%
0.025%
0.050%
0.075%
0.100%
0 4 8 12 16
7654321
BO
LD
Sig
na
l Ch
ang
e
Sequence Length
Lateral PFC
LPFC
@ Decision Neuroscience Scott Huettel, Duke University
McCoy & Platt (2005) Nat Neuro
Ubiquitous Risk Signals
Preuschoff et al. (2007) J Neurosci
Insula
Huettel et al. (2005) J Neurosci
Parietal Cortex
Prefrontal Cortex
Posterior Cingulate
@ Decision Neuroscience Scott Huettel, Duke University
From Glimcher & Rustichini (2004) Science.
@ Decision Neuroscience Scott Huettel, Duke University
Risky - Certain Ambiguous - CertainRisky - Risky Ambiguous - Risky
Trial Types
Trial StructureDecision (RT)
Expectation (4.5-6s)
Outcome (2s)
Huettel et al. (2006) Neuron
Risk vs. Ambiguity
@ Decision Neuroscience Scott Huettel, Duke University
pPAR
LPFC
aINS
LP
FC
Sig
na
l ch
ang
e (
%)
0.12
BO
LD
Pa
ram
ete
rs (
a.u
.)
20 AC AR RC RR
AC AR RC RR
0.2
0.16
Time since trial onset (s)
aIN
Sp
PA
RAC AR RC RR
Trial Type
20
20
L
@ Decision Neuroscience Scott Huettel, Duke University
Risk: Expected Utility Ambiguity: α – MaxMin Expected Utility
Ambiguity PreferringRisk Preferring
Ambiguity AverseRisk Preferring
Ambiguity PreferringRisk Averse
Ambiguity AverseRisk Averse
Subjects (n=13)
@ Decision Neuroscience Scott Huettel, Duke University
Ambiguity Preference
(AC
+ A
R)
– (R
C +
RR
)
Ambiguity preference (1-α) Risk preference (β)
(RC
+ R
R)
- (A
C +
AR
)
Risk Preference
LP
FC
aIN
Sp
PA
R
More (1)(0) Less
More (3)(0) Less
α - Ambiguity β - Risk
Co
rrel
atio
n w
ith
E
con
om
ic
Pre
fere
nc
e
0.0
0.2
0.4
0.6
0.8
1.0
pIFS pPAR
Resampling Analysis
LPFC
Ambiguity… in Lateral Prefrontal Cortex?
@ Decision Neuroscience Scott Huettel, Duke University
Hsu et al. (2005) Science
Ambiguity… in Orbitofrontal Cortex?
@ Decision Neuroscience Scott Huettel, Duke University
Evidence from Cognitive Neuroscience
• Lateral prefrontal cortex– Important for establishing rules for behavior– Implicated in reasoning, response selection
• Orbitofrontal cortex– Important for learning about (aversive) stimuli– Implicated in inhibition of behavior
@ Decision Neuroscience Scott Huettel, Duke University
Interim Take-Home Message
Concepts from decision science are unlikely to reflect unitary psychological constructs nor single neural modules
@ Decision Neuroscience Scott Huettel, Duke University
Conditioning of Risk and Ambiguity
Bach et al. (2009) J Neurosci
Here, ambiguity reflects the expected revelation of information;
i.e., a potentially known unknown.
@ Decision Neuroscience Scott Huettel, Duke University
Stimuli involving ambiguity evoked greater
activation in dlPFC and PPC than those involving
risk or ignorance.
Bach et al. (2009) J Neurosci
@ Decision Neuroscience Scott Huettel, Duke University
pIFS
Huettel & Misiurek (2004)
In a task similar to an implicit Wisconsin Card Sorting Task (i.e., learning rules without immediate
feedback)…
…stimuli that eliminate potential rules evokes activation in lateral
PFC (the posterior inferior frontal sulcus)…
…proportional to the # eliminated rules.
@ Decision Neuroscience Scott Huettel, Duke University
Ventral PFC Damage Increases Risk Seeking
Clark et al. (2008) Brain
Cf. Goel et al. (2007) Cerebral Cortex, who argue for potential laterality effects in reasoning: RH impairs under incomplete
information
@ Decision Neuroscience Scott Huettel, Duke University
Kringelbach (2005) Nat. Rev. Neurosci
Hsu et al. (2005) Science
Puni
shm
ent /
Ave
rsio
n
Plassmann et al. (2007) J. Neurosci.
Rew
ard
/
Valu
e
@ Decision Neuroscience Scott Huettel, Duke University
LPFC
Huettel et al. (2006) Neuron
Hsu et al. (2005) Science
• Ambiguity effects in orbital PFC– Tasks (3): Gambles, knowledge,
opponent– Activation preceded decision (slow)– Aversion led to increased activation– Subject sample: very ambiguity averse
• Ambiguity effects in lateral PFC– Task (1): Gambles– Activation coincident with decision (fast)– Aversion led to decreased activation– Subject sample: ambiguity neutral
Emotional aversion signal: pushes behavior away from ambiguous/risky options?
Cognitive signal: supports creation of decision scenario under ambiguity?
@ Decision Neuroscience Scott Huettel, Duke University
A Lesson from Psychology… for Neuroeconomics?
“A concept that is synonymous with a single operation is nothing more than a restatement of an experimental result. But a concept that arises as a consequence of converging operations has a reality that is independent of any single experimental observation.
“But before we can get convergence, we must introduce variation in our experimental procedures. … Stabilizing on a few techniques… [is] utterly self-defeating… because it completely drops the critical part from critical realism.”
The Processing of Information and Structure p. 187
Wendell “Tex” Garner
@ Decision Neuroscience Scott Huettel, Duke University
Acknowledgments
Support• NIMH, NINDS, NIA• Duke Institute for Brain Sciences
Laboratory Members• McKell Carter• Chris Coutlee• John Clithero• Debra Henninger• O. Mullette-Gillman • Brandi Newell• Allison Scott• David Smith• Adrienne Taren• Vinod Venkatraman• Richard Yaxley
neuroeconomics.duke.edu
Collaborators on these Projects
• Gregory McCarthy• Michael Platt