Predicting Decision M aking from Physiological P redispositions at Rest

1. Predicting Decision Making from Physiological Predispositions at Rest Ariel Telpaz & EldadYechiam

2. Decision Making You are being offered a gamble involving an equal chance of winning or losing 50$. Will you take it? This type of decision resembles real world decisions: • Investing in stocks or bonds • Gambling in the casino • Buying Insurance • Crossing a busy road Can we predict how individuals will behave in such scenarios? Who will chose the risky alternative?

3. Can we Identify Risk takers? Sensation seekers (Zuckerman,1994) - “bored” people who seek to engage in stimulating activities such as taking risks. These individuals are characterized by chronic low levels of arousal during rest. “I do wild things because otherwise I would be bored" CharlieSheen

4. The Pupil Diameter as Measure of Arousal • The eyes are windows to the soul. We can learn about psychological processes from changes in the pupil size. • The Pupil diameter is an index of sympathetic autonomous nervous system activity. This system corresponds with arousal and energy generation. When arousal level increases the pupil dilates. For example, when we are lying our pupil dilates Greg Merson, World Series of Poker player of the year, 2012

5. Resting Arousal Measure • The Pupil diameter of 20 participants was recorded for 30 seconds while they were relaxed and seated comfortably. Resting Arousal = the average Pupil Diameter during the entire period

6. A movie of Resting Pupil Diameter Measurement

7. Decision Making Task 20 participants conducted 3 Decision Tasks consisting of 100 repetitions involving a choice between a risky and safe alternatives. Risk taking is measured as the proportion of times the participant chose the risky alternative. *Gains and Losses tasks - conversion rate 1000 points = 1 shekel

8. A Movie of the Task

9. Individuals with Smaller Resting Pupil Size Took more Risk Gains Mixed Losses The prediction was significantly better in tasks involving losses

10. Frontal Brain Asymmetry • During rest there is an asymmetry in the activity level of the right and left frontal hemispheres • Associated with affective and motivational style(davidson,2004) Increased activation in the frontal Right Hemisphere -High sensitivity to punishments -Increased reactivity to negative stimuli -Higher levels of anxiety • Increased activation in the • frontal Left Hemisphere • -More sensation seeking • -Higher levels of extroversion • -Increased reactivity to Positive stimuli • -High sensitivity to rewards

11. Frontal Brain Asymmetry and risk taking • higher activation of the frontal right hemisphere  withdrawal related motivation Risk averse, focus on the potential large negative outcome involved in risk • higher activation of the frontal left hemisphere  Risk taker, Higher sensitivity to rewards

12. Procedure – Frontal EEG Alpha Asymmetry • We measured the EEG of 57 participants for 4 minutes during rest • Frontal asymmetry index Alpha waves within the frequency range of 8-13 Hz at the frontal left minus the frontal right hemisphere. Alpha activity is inversely related to cortical activation. For example, Alpha waves are prominent when we are meditating or relaxing.

13. Sample of Alpha Activity in the Right and Left Hemispheres of a Single Participant Left Frontal Hemisphere Right Frontal Hemisphere Higher activation of the right frontal hemisphere

14. Movie of the Activity of the Brain During Rest

15. Experience Based Decision Tasks Three experience based decision tasks. Each task consisted of 60 trials. In each trial the participant had to choose one of two alternatives, risky(R) or safe(S):

16. Results • Individuals with Left frontal dominance took more risk. Specifically, in the Mixed task.

17. Brain Activity During the Task • Event related potentials(ERP) measures changes in EEG activity in response to stimuli. • A well known component of the ERP is the P300 - a positive deflection in voltage starting 300 ms following the occurrence of the stimuli. This component is linked with sensitivity to risk. • Only individuals with Left Frontal Dominance exhibited stronger sensitivity to risky outcomes in the P300. P300

18. Brain Activity During the Task • Another well known ERP component is the feedback error related negativity (fERN). • The fERN is a strong negative deflection emerging 200 ms following a financial loss. Only individuals with Right Frontal Dominance had stronger sensitivity to losses at the fERN component. fERN

19. Physiological Predispositions as Predictors of Decision Making Predicting Risk Taking Behavior Resting EEG and Pupil Diameter Can be Used to Predict Risk Taking Behavior in decision making tasks. It is also associated with patterns of brain activity during the task. Losses Moderates the Prediction Power The prediction was much better if the task involved losses. We suggest that losses enhance the level of attention invested in the task and thus increase the reliability of the decision making behavior. With Losses High Attention: Strong Association Behavior Predisposition Low Attention: weak association Without Losses

20. Final Conclusion • Common approach: General and stable link between physiological variable and psychological variable • Interactionist approach (Tett & Gutterman,2000) : The linkage between predisposition and behavior is moderated by cues provided by the environment. Taking this cues into account will improve significantly our ability to predict behavior