Abstract: This paper studies social comparison in networks when sufficiently unfavorable comparisons reduce the marginal return to effort. We capture this mechanism through a convex kink in the status function. The resulting game exhibits strategic substitutability. Under piecewise-linear status, equilibrium behavior is binary and characterized by an endogenous cutoff in local exposure to high-effort peers. Network structure can generate persistent demotivation traps, in which some agents choose low effort in every equilibrium. Despite this demotivation, any equilibrium with low-effort agents weakly Pareto dominates the standard status-competition equilibrium. The underlying strategic-substitutes mechanism extends to a broader class of convex social-comparison preferences, while the binary equilibrium structure and the Pareto result extend to general strictly concave private payoffs.
(with P. Escudié) Misperceived self-control in addiction networks
Abstract: How do mistaken expectations about future self-control alter the propagation of addictive consumption and the targeting of intervention in social networks? We study an infinite-horizon model in which peer-induced consumption accumulates into individual addiction stocks. Naive present-biased consumers correctly understand stock accumulation but expect their future selves to follow a time-consistent adjustment path. Instead, each successive self repeats a present-biased choice and the same forecast error. The network does not transmit mistaken beliefs directly: it transmits the consumption consequences of these beliefs, while addiction carries their effects across time. We characterize the stationary equilibrium and show that, under net harm from addiction, stronger present bias raises long-run consumption, with network-dependent effects when tastes are heterogeneous. In a treatment-based key-player analysis, we show that naivety shapes the propagation of treatment through both the level and stock sensitivity of anticipated future consumption, potentially changing the ranking of treatment targets.
A few works in progress:
(with M. Belhaj) Endogenous social responsiveness in networks
(with M. Belhaj and J. Zheng) An experiment on risk-sharing networks