090822_decneuro_ambiguity_upload.ppt

@ Decision Neuroscience Scott Huettel, Duke University

The Neural Representation of Decision-Making under Uncertainty

Scott Huettel

Psychology & NeuroscienceDuke University

http://www.flickr.com/photos/pkdouyk/sets/72157594512085972/


“…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)


“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


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?


“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


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


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


From Glimcher & Rustichini (2004) Science.


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


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


Risk: Expected Utility Ambiguity: α – MaxMin Expected Utility

Ambiguity PreferringRisk Preferring

Ambiguity AverseRisk Preferring

Ambiguity PreferringRisk Averse

Ambiguity AverseRisk Averse

Subjects (n=13)


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?


Hsu et al. (2005) Science

Ambiguity… in Orbitofrontal Cortex?


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


Interim Take-Home Message

Concepts from decision science are unlikely to reflect unitary psychological constructs nor single neural modules


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.


Stimuli involving ambiguity evoked greater

activation in dlPFC and PPC than those involving

risk or ignorance.

Bach et al. (2009) J Neurosci


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.


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


Kringelbach (2005) Nat. Rev. Neurosci


Puni

shm

ent /

Ave

rsio

n

Plassmann et al. (2007) J. Neurosci.

Rew

ard

/

Valu

e


LPFC

Huettel et al. (2006) Neuron


• 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?


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


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

090822_decneuro_ambiguity_upload.ppt

Documents

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ambiguity bach

ambiguity preferenceac

rr ambiguity preference

neuron risk

term risk

ambiguity neutral lpfc

conditioning of risk