Morality, policy and the brain

Transcription

1 Intelligence and Strategic Behaviour 1 of 43 Morality, policy and the brain Aldo Rustichini Department of Economics, University of Minnesota Vienna Behavioral Economics Network, September 20

2 Brief Philosophical Introduction Intelligence and Strategic Behaviour 2 of 43 Philosophical Introduction Two points of view on human nature A very old debate

3 Brief Philosophical Introduction Intelligence and Strategic Behaviour 2 of 43 Philosophical Introduction Two points of view on human nature A very old debate Individuals are naturally good and generous, but myopic. We may rely on their good instincts, but they need help in their social interaction, for their own good.

4 Brief Philosophical Introduction Intelligence and Strategic Behaviour 2 of 43 Philosophical Introduction Two points of view on human nature A very old debate Individuals are naturally good and generous, but myopic. We may rely on their good instincts, but they need help in their social interaction, for their own good. Individuals are naturally selfish, but clever. Their illuminated self-interest leads to common good outcomes.

5 Brief Philosophical Introduction Intelligence and Strategic Behaviour 2 of 43 Philosophical Introduction Two points of view on human nature A very old debate Individuals are naturally good and generous, but myopic. We may rely on their good instincts, but they need help in their social interaction, for their own good. Individuals are naturally selfish, but clever. Their illuminated self-interest leads to common good outcomes. Some of my best friends think along the first line; there is evidence for both points of view.

6 Brief Philosophical Introduction Intelligence and Strategic Behaviour 2 of 43 Philosophical Introduction Two points of view on human nature A very old debate Individuals are naturally good and generous, but myopic. We may rely on their good instincts, but they need help in their social interaction, for their own good. Individuals are naturally selfish, but clever. Their illuminated self-interest leads to common good outcomes. Some of my best friends think along the first line; there is evidence for both points of view. This debate has gone of for centuries. Here is an example.

7 Brief Philosophical Introduction Philosophical Introduction Those two men have destroyed France (Louis XVI) Intelligence and Strategic Behaviour 3 of 43

8 Brief Philosophical Introduction Philosophical Introduction Those two men have destroyed France (Louis XVI) Intelligence and Strategic Behaviour 3 of 43

9 Brief Philosophical Introduction Philosophical Introduction Those two men have destroyed France (Louis XVI) Intelligence and Strategic Behaviour 3 of 43

10 Brief Philosophical Introduction Intelligence and Strategic Behaviour 4 of 43 Rousseau on Inequality The Second Discours

11 Brief Philosophical Introduction Intelligence and Strategic Behaviour 5 of 43 Rousseau on Inequality The frontispiece

12 Brief Philosophical Introduction Intelligence and Strategic Behaviour 5 of 43 Rousseau on Inequality The frontispiece In the savage state, between the primitive and the civilized, though men had become less patient, and their natural compassion had already suffered some diminution, this period of expansion of the human faculties, keeping a just mean between the indolence of the primitive state and the petulant activity of our egoism, must have been the happiest and most stable of epochs. J.J.Rousseau, A Discourse..., III

13 Brief Philosophical Introduction Intelligence and Strategic Behaviour 6 of 43 The exchange between Voltaire and Rousseau The exchange between Voltaire and Rousseau I have received Sir, your new book against the human species, and I thank you for it.

14 Brief Philosophical Introduction Intelligence and Strategic Behaviour 6 of 43 The exchange between Voltaire and Rousseau The exchange between Voltaire and Rousseau I have received Sir, your new book against the human species, and I thank you for it. No one has ever been so witty as you are in trying to turn us into brutes; to read your book makes one long to go on all fours. As, however, it is now some sixty years since I gave up the practice, I feel that it is unfortunately impossible for me to resume it. Voltaire, letter to Rousseau.

15 Brief Philosophical Introduction Intelligence and Strategic Behaviour 7 of 43 The exchange between Voltaire and Rousseau The Lisbon earthquake

16 Brief Philosophical Introduction Intelligence and Strategic Behaviour 8 of 43 The exchange between Voltaire and Rousseau Marquis of Pombal

17 Brief Philosophical Introduction Intelligence and Strategic Behaviour 9 of 43 The exchange between Voltaire and Rousseau The book

18 Brief Philosophical Introduction Intelligence and Strategic Behaviour 10 of 43 The exchange between Voltaire and Rousseau Fable of the Bees A beehive where all the bees pursue their self interest is thriving Until some begin to lament the lack of morality all the rogues cry d brazenly, Good gods, had we but honesty! Jupiter gives them honesty The desire of a honest and thriving society is: a vain EUTOPIA seated in the Brain

19 Brief Philosophical Introduction Intelligence and Strategic Behaviour 11 of 43 The exchange between Voltaire and Rousseau Three centuries later.. Two experimental studies.

20 Regret and Envy: the rationality of emotions Intelligence and Strategic Behaviour 12 of 43 Introduction Envy is the social correspondent of regret 1. Regret and envy allow us to learn from counterfactual thought; the only difference between the two is that envy considers counterfactual outcomes originated by the choice of others; regret from our own choices

21 Regret and Envy: the rationality of emotions Intelligence and Strategic Behaviour 12 of 43 Introduction Envy is the social correspondent of regret 1. Regret and envy allow us to learn from counterfactual thought; the only difference between the two is that envy considers counterfactual outcomes originated by the choice of others; regret from our own choices 2. The ventromedial prefrontal cortex (vmpfc) encodes the relative value of stimuli during decision-making

22 Regret and Envy: the rationality of emotions Intelligence and Strategic Behaviour 12 of 43 Introduction Envy is the social correspondent of regret 1. Regret and envy allow us to learn from counterfactual thought; the only difference between the two is that envy considers counterfactual outcomes originated by the choice of others; regret from our own choices 2. The ventromedial prefrontal cortex (vmpfc) encodes the relative value of stimuli during decision-making 3. Using a two-player repeated lottery task, we tested whether counterfactual signals generated from comparing the outcome of chosen actions with the outcome of un-chosen actions, or with the outcome of an action chosen by another person, implicate distinct brain networks

23 Regret and Envy: the rationality of emotions Intelligence and Strategic Behaviour 13 of 43 Experimental design Experimental Design: private and social comparisons

24 Regret and Envy: the rationality of emotions Location of lesions A: vmpfc lesions; B: lesions controls Intelligence and Strategic Behaviour 14 of 43 Experimental design

25 Regret and Envy: the rationality of emotions Intelligence and Strategic Behaviour 15 of 43 Private and social counterfactuals Private feedback Impairment of patients with vmpfc lesions

26 Regret and Envy: the rationality of emotions Intelligence and Strategic Behaviour 16 of 43 Private and social counterfactuals Social Feedback No significant relative impairment of patients with vmpfc lesions

27 Regret and Envy: the rationality of emotions Intelligence and Strategic Behaviour 17 of 43 Private and social counterfactuals Choice vmpfc involved in private choice, Dorso-lateral in social

28 Regret and Envy: the rationality of emotions Intelligence and Strategic Behaviour 18 of 43 Conclusions Results Distinct brain mechanisms for private and social counterfactual value signals 1. vmpfc patients were insensitive to private counterfactual value signals, compared to control patients with lesions sparing the prefrontal cortex and healthy controls,

29 Regret and Envy: the rationality of emotions Intelligence and Strategic Behaviour 18 of 43 Conclusions Results Distinct brain mechanisms for private and social counterfactual value signals 1. vmpfc patients were insensitive to private counterfactual value signals, compared to control patients with lesions sparing the prefrontal cortex and healthy controls, 2. But their responses to counterfactual signals based on social comparison were preserved.

30 Regret and Envy: the rationality of emotions Intelligence and Strategic Behaviour 18 of 43 Conclusions Results Distinct brain mechanisms for private and social counterfactual value signals 1. vmpfc patients were insensitive to private counterfactual value signals, compared to control patients with lesions sparing the prefrontal cortex and healthy controls, 2. But their responses to counterfactual signals based on social comparison were preserved. 3. At choice, intact vmpfc was necessary to integrate private counterfactual signals to guide decisions whereas the dorsomedial prefrontal cortex (dmpfc) was more critical in social settings, as shown by the voxel-based lesion-symptom analysis.

31 Regret and Envy: the rationality of emotions Intelligence and Strategic Behaviour 18 of 43 Conclusions Results Distinct brain mechanisms for private and social counterfactual value signals 1. vmpfc patients were insensitive to private counterfactual value signals, compared to control patients with lesions sparing the prefrontal cortex and healthy controls, 2. But their responses to counterfactual signals based on social comparison were preserved. 3. At choice, intact vmpfc was necessary to integrate private counterfactual signals to guide decisions whereas the dorsomedial prefrontal cortex (dmpfc) was more critical in social settings, as shown by the voxel-based lesion-symptom analysis. 4. Conclusion: private and social counterfactual value signals rely on distinct brain mechanisms.

32 Personality and Games Intelligence and Strategic Behaviour 19 of 43 Main Hypotheses Personality, performance and cooperation In single-agent decision problems, the relationship between intelligence, personality and performance is clear: for example, higher intelligence is associated with better outcomes;

33 Personality and Games Intelligence and Strategic Behaviour 19 of 43 Main Hypotheses Personality, performance and cooperation In single-agent decision problems, the relationship between intelligence, personality and performance is clear: for example, higher intelligence is associated with better outcomes; The same is true for zero-sum games;

34 Personality and Games Intelligence and Strategic Behaviour 19 of 43 Main Hypotheses Personality, performance and cooperation In single-agent decision problems, the relationship between intelligence, personality and performance is clear: for example, higher intelligence is associated with better outcomes; The same is true for zero-sum games; When the interaction is strategic and there is room for cooperation, instead, the link is complex. In occasional (one shot) interactions may be paradoxical (higher intelligence individuals behaving further from game theoretic predictions)

35 Personality and Games Intelligence and Strategic Behaviour 20 of 43 Experimental Design and Implementation Games used in the experiments In our experiments we consider repeated games with a symmetric two players-two actions stage game. We consider in particular: Prisoner s dilemma (PD), Battle of Sexes (BoS), Stag Hunt (DH) and a game that we defined as the Battle of the Sexes with Compromise (BoSC) (a version of the chicken game).

36 Personality and Games Intelligence and Strategic Behaviour 20 of 43 Experimental Design and Implementation Games used in the experiments In our experiments we consider repeated games with a symmetric two players-two actions stage game. We consider in particular: Prisoner s dilemma (PD), Battle of Sexes (BoS), Stag Hunt (DH) and a game that we defined as the Battle of the Sexes with Compromise (BoSC) (a version of the chicken game). These games are complete representatives of all strategic situations that allow cooperation

37 Personality and Games Experimental Design and Implementation Create two cities Intelligence and Strategic Behaviour 21 of 43

38 Personality and Games Experimental Design and Implementation wo cities Create two cities Belmont Intelligence and Strategic Behaviour 21 of 43 Fishtown

39 Personality and Games Intelligence and Strategic Behaviour 22 of 43 Experimental Design and Implementation Time line Day 1: Collect demographics, risk attitude and personality measures, and test subjects on IQ (Raven Test); Between day 1 and day 2: Allocate subjects in low Raven score and high Raven score groups Day 2: Participants Play the games repeatedly with random matching and a given continuation probability

40 Personality and Games Intelligence and Strategic Behaviour 23 of 43 Experimental Design and Implementation Day One: Raven Test

41 Personality and Games Intelligence and Strategic Behaviour 24 of 43 Experimental Design and Implementation Group composition Prisoner s dilemma with high continuation probability (0.75)

42 Personality and Games Intelligence and Strategic Behaviour 25 of 43 Intelligence in Prisoner s Dilemma Repeated Prisoner s Dilemma: natural equilibrium outcome C D C 48,48 12, 50 D 50,12 25,25

43 Personality and Games Intelligence and Strategic Behaviour 26 of 43 Intelligence in Prisoner s Dilemma Repeated Prisoner s Dilemma: conflict C D C 48,48 12, 50 D 50,12 25,25

44 Personality and Games Intelligence and Strategic Behaviour 27 of 43 Intelligence in Prisoner s Dilemma Prisoner s Dilemma with High Continuation Probability IQ separated treatments

45 Personality and Games Intelligence and Strategic Behaviour 28 of 43 Intelligence in Prisoner s Dilemma Prisoner s Dilemma with Low Continuation Probability IQ separated treatments

46 Personality and Games Intelligence and Strategic Behaviour 29 of 43 Intelligence in Battle of the Sexes with a Compromise Battle of the Sexes with a Compromise W B B 52,12 10,10 W 48,48 12,52

47 Personality and Games Intelligence and Strategic Behaviour 30 of 43 Intelligence in Battle of the Sexes with a Compromise Battle of the Sexes with a Compromise: natural equilibrium W B B 52,12 10,10 W 48,48 12,52

48 Personality and Games Intelligence and Strategic Behaviour 31 of 43 Intelligence in Battle of the Sexes with a Compromise Battle of the Sexes with a Compromise: conflict W B B 52,12 10,10 W 48,48 12,52

49 Personality and Games Intelligence and Strategic Behaviour 32 of 43 Intelligence in Battle of the Sexes with a Compromise Battle of Sexes with compromise High continuation probability

50 Personality and Games Intelligence and Strategic Behaviour 33 of 43 Reason of the difference Why the difference between the groups? Conditional cooperation per period. PD with High Continuation Probability.

51 Personality and Games Intelligence and Strategic Behaviour 34 of 43 Reason of the difference Why the difference between the groups? Conditional cooperation per period. BoSC with High Continuation Probability.

52 Personality and Games Intelligence and Strategic Behaviour 35 of 43 Reason of the difference Errors and Intelligence

53 Personality and Games Intelligence and Strategic Behaviour 36 of 43 Intelligence in Stag Hunt Stag Hunt S H S 48,48 0,25 H 25,0 25,25

54 Personality and Games Intelligence and Strategic Behaviour 37 of 43 Intelligence in Stag Hunt Stag Hunt: no conflict at the natural equilibrium S H S 48,48 0,25 H 25,0 25,25

55 Personality and Games Intelligence and Strategic Behaviour 38 of 43 Intelligence in Stag Hunt Stag Hunt High continuation probability

56 Personality and Games Intelligence and Strategic Behaviour 39 of 43 Intelligence in Battle of the Sexes Battle of the Sexes W B B 52,12 0,0 W 0,0 12,52

57 Personality and Games Intelligence and Strategic Behaviour 40 of 43 Intelligence in Battle of the Sexes Battle of Sexes High continuation probability

58 Personality and Games Intelligence and Strategic Behaviour 41 of 43 Effect of Agreeableness and Conscientiousness Low and high Conscientiousness sessions PD with High Continuation Probability

59 Personality and Games Intelligence and Strategic Behaviour 42 of 43 Effect of Agreeableness and Conscientiousness Low and high Agreeableness sessions PD with High Continuation Probability

60 Conclusions Intelligence and Strategic Behaviour 43 of 43 Summary of Main Results Cognitive skills have a large and positive long-run effect on cooperative behavior in the games where there is a conflict between short-run gains and long-run losses Initially similar, cooperation rates for groups with different cognitive skills diverge, declining in groups of lower skills, and increasing to reach almost full cooperation levels in groups of higher skills Cooperation levels exhibited by more skilled subjects are payoff sensitive, and not unconditional Personalty traits such as Agreeableness and Conscientiousness have positive, but transitive effects.