Results: Conflict

1. L INS R AMG R SPL two regions L mid OFC R HIPP L HIPP Society for Neuroeconomics Annual conference September 25-28, 2008 at The Canyons, Park City, Utah) • Neurobiological responses in individuals making choices in uncertain environments: Ambiguity and Conflict. Helen Pushkarskaya, Xun Liu, Michael Smithson, Jane E. Joseph University of Kentucky, The Australian National University • Discussion • The study is now at the stage of interpreting the results. • Several preliminary conclusions can be made: • Two uncertain environments with known outcomes but unknown probabilities – Ambiguity (vague information about probabilities) and Conflict (conflicting information about probabilities) – are supported by distinct neurobiological networks. • Ambiguity seems to provoke the “rest and repose” response in individuals (associated with activation in the left insula; Craig, 2005). • Conflict seems to provoke the “fear” response (associated with activation in the brainstem, the bilateral hippocampus, and the right amygdala; Sah and Westbrook, 2008), and more strongly than other types of uncertainty recruits “top-down and bottom-up” attention to memory networks (associated with the bilateral superior parietal lobe and bilateral inferior parietal lobe respectively; Ciaramelli, Grady & Moscovitch, 2008). • Ambiguity aversion predicts activation in the left mid OFC (associated with anticipation anxiety; Chua et al., 1999). • Conflict aversion predicts activation in the right superior parietal (associated with short term working memory; Otsuka, Y., Osaka, N. & Osaka, M., 2008). • Traditionally uncertainty was associated with the lack of information about outcomes/probabilities, however our results suggest that more careful attention should be paid to the environments with available, but conflicting information about outcomes/probabilities. Introduction Ellsberg defined ambiguity as an environment “when there are questions of reliability and relevance of information, and particularly where there is conflicting opinions and evidence” (Ellsberg, 1961, p. 659). However, as Budescu and Wallsten (1995) pointed out, the studies of decision making under ambiguity (for review see Camerer & Weber, 1992) had focused only on environments with imprecise probabilities rather than on unknown probabilities. Later, Smithson (1999) suggested considering an environment where equally reliable sources provide conflicting information about probabilities associated with known outcomes (conflict) separately from environments where vague probabilities are associated with known outcomes (ambiguity). Existing behavioral studies of conflict (Smithson,1999; Cabantous, 2007) suggest that conflicting unambiguous messages from two equally believable sources are less preferred than two informatively equivalent, ambiguous, but agreeing messages from the same sources (i.e., conflict aversion); and conflicting unambiguous sources are perceived as less credible than ambiguous but agreeing sources. Research question: Do people respond differently to ambiguity and conflict on the neurobiological level? (C) CONFLICT SPECIFIC (A) AMBIGUITY SPECIFIC (MI) AMBIGUITY AND IGNORANCE CONJOINED Results: Ambiguity Results: Conflict • Method • Participants • 42 right-handed healthy participants (21 males and 21 females); 1 male and 3 females were excluded from the fMRI analysis because of the large (>4mm) head motion. • Stimuli • The probabilities of card one and card two + card three were matched across all gambles. • Procedure • Participants made their choices ($3 sure gain or bet on one of three cards) during fMRI scanning. One randomly chosen gamble from each condition was played after the fMRI session. The outcomes of these gambles determined participants’ payment. Behavioral data was used to derive individual (dis) preferences toward ambiguity and conflict (pessimism/optimism about probabilities). Selective activation by Ambiguity (Ambiguity > Risk & Conflict & SSI) Selective activation by Conflict (Conflict > Risk & Ambiguity & SSI) Right Amygdala R Hippocampus L hippocampus Brainstem R A SSI C R A SSI C R A SSI C R A SSI C References Chua, P., Krams, M., Toni, I., Passingham, R., & Dolan, R. (1999). A Functional Anatomy of Anticipatory Anxiety. NeuroImage, 9 (6), 563-571. Ellsberg, D. (1961). Risk, Ambiguity, and the Savage Axioms. Quarterly Journal of Economics, 75, pp. 643-669. Otsuka, Y., Osaka, N. & Osaka, M. (2008). Functional asymmetry of superior parietal lobule for working memory in the elderly. Neuroreport. 19(14):1355-1359 Budescu, D., & Wallsten, T. (1995). Processing Linguistic probabilities: general principles and empirical evidence. In H. R. Busemeyer J. (Ed.), Decision Making from a Cognitive Perspective (pp. 275-318). San Diego: Academic Press. Cabantous, L. (2007). Ambiguity aversion in the field of insurance: insurers' attitude to imprecise and conflicting probability estimates. Theory and Decision, 62, pp. 219-240. Camerer, C., & Weber, M. (1992). Recent Developments in Modeling Preferences: Uncertainty and Ambiguity. Journal of Risk and Uncertainty, 5 (4), pp. 325-370. Ciaramelli, E., Cheryl L. Grady, C, L. & Moscovitch, M. (2008). Top-down and bottom-up attention to memory: A hypothesis (AtoM) on the role of the posterior parietal cortex in memory retrieval. Neuropsychologia 46 (7), 1828-1851 Craig A.D. (2005) Forebrain emotional asymmetry: a neuroanatomical basis? Trends in Cognitive Sciences 9 (12), 566-571 Sah1, P. & Westbrook, R. F.(2008) Behavioural neuroscience: The circuit of fear. Nature 454, 589-590 Smithson, M. (1999). Conflict Aversion: Preference for Ambiguity vs. Conflict in Sources and Evidence. Organizational Behavior and Human Decision Processes, 79, pp. 179-198. Condition of interest Correlation with individual ambiguity aversion, g1 Correlation with individual conflict aversion, g2 a) Risk b) Ambiguity Left Insula Condition of interest c) Conflict d) Sample Space Ignorance A SSI R C Summary of the results for brain activation associated with Ambiguity condition Summary of the results for brain activation associated with Conflict condition Acknowledgements This research was supported by the grant from the Research Foundation of the University of Kentucky. We thank Christine Corbly for her technical assistance.