arXiv subjects

Luca Paolo Merlino

Publications and source records attributed to Luca Paolo Merlino.

5 recordsLinked to original sources

arXiv2026

A Model of Polarization on Social Media

We develop a model of social media in which users produce different types of content and choose whom to follow. Even when abstracting from algorithmic bias, linking costs shape networks and polarization. In the welfare-maximizing equilibrium, lower linking costs can raise welfare but also increase exposure to extreme content, while very low costs reduce welfare and heighten polarization by discouraging moderate contributors. Policies that incentivize content provision can generate large welfare gains by changing who produces information, whereas link subsidies or attention reallocation mainly affect exposure and have limited welfare impact. These insights help explain why exposure-based interventions on social media platforms often yield ambiguous effects on polarization.

econ.TH↗

arXiv2026

Optimal Verification of (Mis)Information in Networks

We study the diffusion of a true and a false message (misinformation) when agents are biased and able to verify messages. As a recipient of a false message who verifies it becomes informed of the truth, a higher prevalence of misinformation can increase the prevalence of the truth. We uncover conditions such that this happens and discuss policy implications. Specifically, a planner aiming to maximize the prevalence of the truth should allow misinformation to circulate if: non-verified messages may be ignored, transmission of information is relatively low, and the planner's budget to induce verification is neither too low nor too high. Homophily increases the spread of misinformation, but also facilitates diffusion of truth, and leads to similar results on the effect of verification.

econ.TH↗

arXiv2022

Group Identity, Social Learning and Opinion Dynamics

In this paper, we study opinion dynamics in a balanced social structure consisting of two groups. Agents learn the true state of the world naively learning from their neighbors and from an unbiased source of information. Agents want to agree with others of the same group--in-group identity -- but to disagree with those of the opposite group--out-group conflict. We characterize the long-run opinions, and show that agents' influence depends on their Bonacich centrality in the signed network of opinion exchange. Finally, we study the effect of group size, the weight given to unbiased information and homophily when agents in the same group are homogeneous.

econ.TH↗

arXiv2022

Marriage through friends

In this paper, we propose a model of the marriage market in which individuals meet potential partners either directly or through their friends. When socialization is exogenous, a higher arrival rate of direct meetings also implies more meetings through friends. When individuals decide how much to invest in socialization, meetings through friends are first increasing and then decreasing in the arrival rate of direct offers. Hence, our model can rationalize the negative correlation between the advent of online dating and the decrease of marriages through friends observed in the US over the past decades.

econ.TH↗

arXiv2021

Free Riding in Networks

Players allocate their budget to links, a local public good and a private good. A player links to free ride on others' public good provision. We derive sufficient conditions for the existence of a Nash equilibrium. In equilibrium, large contributors link to each other, while others link to them. Poorer players can be larger contributors if linking costs are sufficiently high. In large societies, free riding reduces inequality only in networks in which it is initially low; otherwise, richer players benefit more, as they can afford more links. Finally, we study the policy implications, deriving income redistribution that increases welfare and personalized prices that implement the efficient solution.

econ.TH↗