The Neural Representation of Decision-Making under Uncertainty

1. The Neural Representation of Decision-Making under Uncertainty Scott Huettel Psychology & Neuroscience Duke University @ Decision Neuroscience Scott Huettel, Duke University

2. “…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

3. “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

4. 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

5. “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

6. @ Decision Neuroscience Scott Huettel, Duke University

7. Lateral PFC Sequence Length LPFC BOLD Signal Change LPFC Huettel, Mack, & McCarthy (2002) Nature Neuroscience @ Decision Neuroscience Scott Huettel, Duke University

8. Insula Preuschoff et al. (2007) J Neurosci Parietal Cortex McCoy & Platt (2005) Nat Neuro Prefrontal Cortex Huettel et al. (2005) J Neurosci Ubiquitous Risk Signals Posterior Cingulate @ Decision Neuroscience Scott Huettel, Duke University

9. From Glimcher & Rustichini (2004) Science. @ Decision Neuroscience Scott Huettel, Duke University

10. Risk vs. Ambiguity Trial Types Risky - Certain Risky - Risky Ambiguous - Certain Ambiguous - Risky Trial Structure Decision (RT) Expectation (4.5-6s) Outcome (2s) Huettel et al. (2006) Neuron @ Decision Neuroscience Scott Huettel, Duke University

11. 0.12 LPFC LPFC BOLD Parameters (a.u.) Signal change (%) aINS 20 AC AR RC RR 0.16 aINS pPAR AC AR RC RR 20 0.2 pPAR AR RC RR AC 20 Trial Type Time since trial onset (s) L @ Decision Neuroscience Scott Huettel, Duke University

12. Ambiguity Averse Ambiguity Averse Risk Averse Risk Preferring Ambiguity Preferring Ambiguity Preferring Risk Averse Risk Preferring Risk: Expected Utility Ambiguity: α – MaxMin Expected Utility Subjects (n=13) @ Decision Neuroscience Scott Huettel, Duke University

13. Ambiguity… in Lateral Prefrontal Cortex? Ambiguity Preference Risk Preference (0) Less More (3) (RC + RR) - (AC + AR) (AC + AR) – (RC + RR) α - Ambiguity β - Risk LPFC (0) Less More (1) Correlation with Economic Preference aINS LPFC Resampling Analysis pPAR Ambiguity preference (1-α) Risk preference (β) @ Decision Neuroscience Scott Huettel, Duke University

14. Ambiguity… in Orbitofrontal Cortex? Hsu et al. (2005) Science @ Decision Neuroscience Scott Huettel, Duke University

15. 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

16. Interim Take-Home MessageConcepts from decision science are unlikely to reflect unitary psychological constructs nor single neural modules @ Decision Neuroscience Scott Huettel, Duke University

17. Conditioning of Risk and Ambiguity Here, ambiguity reflects the expected revelation of information; i.e., a potentially known unknown. Bach et al. (2009) J Neurosci @ Decision Neuroscience Scott Huettel, Duke University

18. 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

19. 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. pIFS Huettel & Misiurek (2004) @ Decision Neuroscience Scott Huettel, Duke University

20. 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

21. Punishment / Aversion Reward / Value Hsu et al. (2005) Science Plassmann et al. (2007) J. Neurosci. Kringelbach (2005) Nat. Rev. Neurosci @ Decision Neuroscience Scott Huettel, Duke University

22. Emotional aversion signal: pushes behavior away from ambiguous/risky options? • 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 Hsu et al. (2005) Science LPFC Cognitive signal: supports creation of decision scenario under ambiguity? Huettel et al. (2006) Neuron @ Decision Neuroscience Scott Huettel, Duke University

23. 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

24. neuroeconomics.duke.edu Acknowledgments Collaborators on these Projects • Gregory McCarthy • Michael Platt 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 @ Decision Neuroscience Scott Huettel, Duke University