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090822_DecNeuro_Ambiguity_Upload.ppt 090822_DecNeuro_Ambiguity_Upload.ppt Presentation Transcript

  • The Neural Representation of Decision-Making under Uncertainty Scott Huettel Psychology & Neuroscience 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)
  • “ 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?
  • Wendell “Tex” Garner “ 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.
  • LPFC Huettel, Mack, & McCarthy (2002) Nature Neuroscience BOLD Signal Change Sequence Length Lateral PFC LPFC
  • Ubiquitous Risk Signals Posterior Cingulate McCoy & Platt (2005) Nat Neuro Preuschoff et al. (2007) J Neurosci Insula Huettel et al. (2005) J Neurosci Parietal Cortex Prefrontal Cortex
  • From Glimcher & Rustichini (2004) Science .
  • Risky - Certain Ambiguous - Certain Risky - Risky Ambiguous - Risky Trial Types Trial Structure Decision (RT) Expectation (4.5-6s) Outcome (2s) Huettel et al. (2006) Neuron Risk vs. Ambiguity
  • L pPAR LPFC aINS LPFC Signal change (%) 0.12 BOLD Parameters (a.u.) 20 AC AR RC RR AC AR RC RR 0.2 0.16 Time since trial onset (s) aINS pPAR AC AR RC RR Trial Type 20 20
  • Risk: Expected Utility Ambiguity: α – MaxMin Expected Utility Subjects (n=13) Ambiguity Preferring Risk Preferring Ambiguity Averse Risk Preferring Ambiguity Preferring Risk Averse Ambiguity Averse Risk Averse
  • Ambiguity… in Lateral Prefrontal Cortex? Ambiguity Preference (AC + AR) – (RC + RR) Ambiguity preference (1- α ) Risk preference (β) (RC + RR) - (AC + AR) Risk Preference LPFC aINS pPAR More (1) (0) Less More (3) (0) Less α - Ambiguity β - Risk Correlation with Economic Preference Resampling Analysis LPFC
  • Ambiguity… in Orbitofrontal Cortex? Hsu et al. (2005) Science
  • 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 Hsu et al. (2005) Science Punishment / Aversion Plassmann et al. (2007) J. Neurosci. Reward / Value
    • 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
    LPFC Huettel et al. (2006) Neuron Hsu et al. (2005) Science 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
    • 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
    • Collaborators on these Projects
    • Gregory McCarthy
    • Michael Platt