Successful climate change adaptation depends on the spread and maintenance of novel adaptive behaviors. Social structure is a fundamental determinant of the spread of innovations and evolution of cumulative culture. Current theory suggests that the heterogeneity of metapopulation structure can help foster the diffusion of innovations. In this paper, we develop an agent-based model of the spread of adaptations in populations with such minority-majority metapopulation structure, where subpopulations have different preferences for social interactions (i.e., homophily) and, consequently, learn deferentially from their own group. In our simulations, minority-majority-structured populations with moderate degrees of in-group preference better spread and maintained an adaptation compared to populations with more equal-sized groups and weak homophily. Minority groups act as incubators for a novel adaptations, while majority groups act as reservoirs for the adaptation once it has spread widely. This suggests that population structure with in-group preference could promote the maintenance of novel adaptations, in the absence of out-group aversion. Our work advances the goal of this special issue by developing new theoretical insights and demonstrating the utility of cultural evolutionary theory and methods as important tools in the nascent science of culture that adaptation needs.

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work is licensed under a Creative Commons IGO 3.0 AttributionNonCommercial-NoDerivatives (CC-IGO BY-NC-ND 3.0 IGO) license (http://creativecommons.org/licenses/by-nc-nd/3.0/igo/ legalcode) and may be reproduced with attribution to the IDB and for any non-commercial purpose, as provided below. No derivative work is allowed.Any dispute related to the use of the works of the IDB that cannot be settled amicably shall be submitted to arbitration pursuant to the UNCITRAL rules. The use of the IDB's name for any purpose other than for attribution, and the use of IDB's logo shall be subject to a separate written license agreement between the IDB and the user and is not authorized as part of this CC-IGO license.Following a peer review process, and with previous written consent by the Inter-American Development Bank (IDB), a revised version of this work may also be reproduced in any academic journal, including those indexed by the American Economic Association's EconLit, provided that the IDB is credited and that the author(s) receive no income from the publication. Therefore, the restriction to receive income from such publication shall only extend to the publication's author(s). With regard to such restriction, in case of any inconsistency between the Creative Commons IGO 3.0 Attribution-NonCommercial-NoDerivatives license and these statements, the latter shall prevail.Note that link provided above includes additional terms and conditions of the license.The opinions expressed in this publication are those of the authors and do not necessarily reflect the views of the Inter-American Development Bank, its Board of Directors, or the countries they represent. ABSTRACTIt is a well-known fact that a great majority of countries implement agricultural input subsidies as a tool to boost agricultural productivity and output. However, even though this practice is widely spread and represents a large part of the agricultural budget, little emphasis has been placed on the evaluation of the effectiveness of such schemes. This paper aims to shed light on this issue by exploring the impact of agricultural input subsidies on agricultural productivity. Using a quasiexperimental approach (Propensity Score Matching), this study estimates the impact of receiving an agricultural input donation on the value of production per hectare as a measure of the effect on agricultural productivity. To this end, data from the "Encuesta Permanente de Hogares" of Paraguay, a nationally representative household survey collected in 2012, was utilized. The results provide evidence that agricultural input donations do not have an impact on agricultural productivity or input utilization.

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