Biometric responses to unjustified and justified-envy in school choice allocations

The two most prominent strategy-proof school choice mechanisms, Deferred Acceptance and Top Trading Cycles, offer a trade-off between eliminating justified-envy and Pareto efficiency, respectively. We introduce a novel, biometric approach to investigate how much individuals care about and physiologically react to each property. Using an experimental design that randomly varies whether subjects learn about others’ assignments in a school choice game, we measure arousal through galvanic skin response and valence through facial expressions when subjects experience envy with and without justification. We find increased arousal associated with receiving successively lower-ranked allocations, i.e., the (unjustified) envy of the allocation(s) of others. We note additional arousal when that envy is justified, but that result requires an explicit message to accentuate the justification. Eye-tracking data confirm that subjects do not notice markers of justified-envy until receiving this message. Facial-expression valence yields less conclusive results, but this may be due to the limitations of that method for anger detection.