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Cognitive Load and Strategic Sophistication. Sarah Allred Sean Duffy John Smith Psychology Psychology Economics Rutgers University-Camden. Beauty Contest-Laboratory Outcomes. Models of Strategic Sophistication.
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Cognitive Load and Strategic Sophistication Sarah Allred Sean Duffy John Smith Psychology Psychology Economics Rutgers University-Camden
Models of Strategic Sophistication • Level-k/Cognitive Hierarchy Models • Stahl and Wilson, 1994, 1995; Nagel, 1995; Costa-Gomes et al., 2001; Camerer et al., 2004 • Different levels of strategic sophistication • Very successful in interpreting • heterogeneous experimental data
Strategic Sophistication (continued) • Does the observed strategic sophistication • relate to a fundamental characteristic of the subject? • Examine relationship between • measures of cognitive ability and • strategic behavior • Ballinger et al. (2011), Bayer and Renou (2011), Brañas-Garza et al. (2012), Brañas-Garza et al. (2011), Burnham et al. (2009), Carpenter et al. (2013), Chen et al. (2009), Chen et al. (2011), Devetag and Warglien (2003), Georganas et al. (2010), Gill and Prowse (2012), Jones (2011), Jones (2008), Palacios-Huerta (2003), Putterman et al. (2011) and Rydval (2011)
Experimental • Rather than measure cognitive ability • We manipulate it • Advantage to manipulating cognitive ability • Cognitive ability related to lots of other things • Maybe X determines strategic sophistication • And X merely related to cognitive ability • Complementary means of investigating effects of • Cognitive ability • on strategic behavior
How to think about the manipulation? • Discovered crayon in • Homer Simpson’s brain • Was causing cognitive shortcomings Homer without crayon in brain Homer with crayon in brain
How to Manipulate Cognitive Resources? • Cognitive Load • Task which occupies cognitive resources • Unable to devote to deliberation • Observe behavior
Cognitive Load in Games • Cognitive load and games • Roch et al. (2000) • Cappelletti et al. (2008) • Duffy and Smith (2012) • Not designed to measure strategic sophistication • Carpenter, Graham, Wolf (2013)
Experiment Details • 164 Subjects • Rutgers-New Brunswick • Sessions of • 16 or 20 • Earned average $17.89 • z-Tree • Fischbacher (2007)
Cognitive Load Treatments • Before play in each period • Subjects given number • to commit to memory • Up to 15 seconds • After play in game • asked for the number • High Load • 9 digit number • of 0’s and 1’s • First digit always 1 • Low Load • 3 digit number • of 0’s and 1’s • First digit always 1
Discussion of Cognitive Load • Alternate load • High • Low • Mandatory rest period • 20 seconds between the rounds • Why 0’s and 1’s? • Did not want the number to interact with decision
Timeline across periods • Ten 3x3 games • Pay 3 randomly selected if 10 memorization correct • Pay 2 if 9 correct • Pay 1 if 8 correct • Pay 0 if less than 8 • Version of 11-20 Game • Version of Beauty Contest • Only paid if memorization correct for both • Randomly matched every period • No feedback
3x3 Games • Always shown as row player • All payoffs • between 1 and 11 points • 10 points = $3.50 • Unique NE • To specify action • And point beliefs of other’s action • Correct beliefs • earn 4 additional points
Manipulation Checks • Load Time • High Load: 10.3 seconds • Low Load: 2.4 seconds • p<0.001 • Correct Memorization Task • Low Load: 98.8% • High Load: 97.1% • p=0.004
Characterize Games • Measure of Easiness • Sum of dominated strategies • Of Initial Game • Own and Other • Range from 0 to 4 • Measure of Asymmetry • Absolute value of • Difference between • number of own dominated strategies • And number of other’s dominated strategies • Range from 0 to 2
Characterize Strategic Behavior • Is the subject selecting the best action • Given that the opponent is selecting each action • with prob 0.33? • L1 is not particularly sophisticated • L1 classification behavior • 1 if behavior consistent with L1 • 0 otherwise
Repeated measures regressions • Regressions • Unstructured covariance matrix within subjects • And across observations • Each regression has 1640 observations • (164 subjects playing 10 games) • Provide coefficient estimates and p-values
3x3 games-L1 Classification High load subjects more likely to be classified as L1 High load subjects less sensitive to complexity of the game
3x3 games-Wrap-up • Consistent with reduction of cognitive resources • High load subjects • Less strategic • Consistent with L1
Our version of 11-20 Game • Adapted from Arad and Rubenstein (2012) • Subjects are paired • Each selects an integer • between 1 and 10 • Receive request • 10 points = $3.50 • Earn a bonus of 10 if select exactly • one lower than opponent • Allows straightforward measure • of strategic thinking • Instructions were given before load • Equilibrium • 10 w prob. 0.1 • 9 w prob. 0.2 • 8 w prob. 0.3 • 7 w prob. 0.4
1-10 Game Response • Bounded above by 10 • And below by 1 • Run tobit regressions with these bounds
1-10 Game Response High load subjects are more strategic No evidence that self-reported GPA related to choice
1-10 Game Response • High load more sophisticated! • (Not less!!!!!) • High Load subjects • expect to face more cognitively able opponent • Low Load subjects • expect to face less cognitively able opponent • High Load highlights own limitations
Our version of Beauty Contest • Every subject selects a half integer • between 0 and 10 • Winner guesses closest to • 2/3 of average • Wins $30 • Bounded between 0 and 10 • Run tobit regressions with these bounds
Beauty Contest Game Response High load subjects are less strategic Relationship between self-reported GPA and strategic sophistication
1-10 and Beauty Contest Wrap-up • 1-10 game • High load • more strategic • Uncomplicated game • Play 1 less • than the other guy • Self-reported GPA • not related choice • Beauty contest • High load • less strategic • Complicated game • Guess 2/3 • of the average of the session • Self-reported GPA • related to choice
New Strategic Sophistication Papers • Strategic sophistication is the result of 1. Subject’s own ability to make computations 2. Subject’s perception of opponent • Agranov, Potamites, Schotter, and Tergiman(2012) • Alaouiand Penta (2012)
1-10 and Beauty Contest Wrap-up • Two effects of reduced cognitive resources 1. Reduced ability to make computations 2. Reduction place in distribution of cognitive resources of subjects • 2 dominates 1 in 1-10 game • Relatively uncomplicated • 1 dominates 2 in beauty contest game • Relatively complicated
Conclusion • Cognitive load helpful in examining relationship • between cognitive ability and • strategic behavior • Pay attention to both • Cognitive ability and • Perception of cognitive ability of others
Future Work • Observe timing of the • Action and belief decisions • 9 binary digits too easy to remember? • Tell subjects Nash Equilibrium • Cognitive resources devoted to behavior of other • Do not solicit beliefs • Perhaps prompts subjects to be more strategic