報告タイトル：Civil War and Insect Food Culture in Cambodia (joint work with Satoru Shimokawa)

報告概要：Cultural practices shape economic behavior, yet the mechanisms underlying their emergence and persistence remain poorly understood. We explore the evolution of food culture in Cambodia, focusing on the adoption of insect consumption during and after the civil war. We find that villages with higher mortality during the Pol Pot regime (1975-1979) and greater returnee presence in the 1990s exhibit significantly higher rates of insect consumption today—primarily driven by the influence of returnees. We discuss the underlying mechanisms by developing a dynamic model of cultural evolution that formalizes how historical shocks, habit formation, and social influence determine whether cultural practices emerge, persist, or disappear over time.

 報告タイトル：The Pitfalls of Accelerating Entrepreneurship: How Nascent Entrepreneurial Activity Affects Start-up Size

報告概要：To assess whether accelerating entrepreneurial activity yields positive outcomes, this study examines the impact of nascent entrepreneurial activity—specifically its duration—on start-up size. Drawing on data from new firms in Japan, we find that start-up size increases with longer preparation, but the relationship is nonlinear: beyond a certain point, extended nascent activity leads to smaller firms, indicating an inverted U-shaped pattern. Furthermore, among entrepreneurs with prior management experience, longer preparation is associated with even smaller start-ups. We further identify which types of nascent activities most strongly influence start-up size. These findings have important implications for both policy and practice.

 報告タイトル：The impact of US export controls on firm’s export behavior in a third country: Evidence from Japanese Customs data

報告概要：This study examines the impact of US export controls against Chinese firms on Japanese firms’ export behavior using Japan Customs data. In particular, this study focuses on the impact of the Entity List (EL) issued by the US Bureau of Industry and Security. We identify exports from Japanese firms to each Chinese firm that was added to the EL by the end of 2022. We find that the addition of Chinese firms to the EL significantly reduced Japanese firms’ exports to those targeted firms. Instead, these affected Japanese firms increased exports to non-targeted Chinese firms and firms in US allies. 

 報告タイトル：Eclipse: How Darkness Shapes Violence in Africa

報告概要：Although darkness has long been associated with insecurity, the link remains speculative. I fill the gap by examining the effect of solar eclipses on violence. Expanding on psychological theories, I hypothesize that eclipse-induced darkness evokes fear, which in turn is misattributed to outgroups, thereby triggering violence. I contrast this argument with a tactical explanation, suggesting that darkness allows armed groups to secretly kill civilians. I test the “eclipse effect” by exploiting exogenous variations in the dates and locations of solar eclipses for 1997–2022 in Africa. The analysis indicates a spike in violence on the days of solar eclipses. To explore the mechanisms, I examine the initiators and original texts of violent events, weather conditions, ethnic folklore, and individual-level surveys. The analyses support the tactical rather than psychological explanation. These findings warn against assuming that “irrational” or “superstitious” African people overreacted to eclipses; armed groups rationally can use darkness for their tactical purposes.

 報告タイトル：Business Expectations and Forecast Errors in the Interconnected Economy

報告概要：We construct a unique data set that contains information about business expectations, forecast errors, and business transaction relationships to o!er a new perspective on mechanisms for the formation of business expectations and the generation and transmission of forecast errors. Our main empirical findings are as follows: Firms’ expectations about their growth rates are positively correlated with the number of transaction partners, consistent with firm growth patterns. A longer duration of transaction relationships tends to reduce uncertainty and forecast errors, suggesting the role of information sharing and flexible adjustments in forecasting. A larger forecast variation tends to amplify forecast errors, indicating that uncertainty is a major factor in forecast errors. A firm’s forecast error is transmitted to its transaction partners. These forecast error correlations arise from transaction linkages, not more aggregate factors. This study advances our understanding of how firms form business expectations in an interconnected economy and how forecast errors are transmitted between transaction partners.

 報告タイトル：Overkill, Extinction, and the Neolithic Revolution

報告概要：This research explores the biogeographical origins of the emergence and spread of agriculture. The theory suggests that mammal species with certain biological traits were more vulnerable to hunting pressure, leading to their extinction. This reduced hunting resources, which in turn pushed humans toward agriculture. To test this hypothesis, I create a measure that captures the loss of hunting resources due to extinction. By using various complementary datasets, controlling for ancient climatic factors, and leveraging certain biological traits that raise extinction risk as exogenous factors, the research shows that the extinction of large herbivores significantly contributed to the Neolithic Revolution.

 報告タイトル：Industrial Subsidies along Domestic Value Chains and their Impacts on China’s Exports

報告概要：Industrial subsidies are at the center of the recent political and economic debate. This paper examines the impacts of subsidies along domestic value chains on the export performance of Chinese firms. Using firm-level subsidy data and inter-provincial input-output tables with firm ownerships, we measure direct subsidies and indirect subsidies in upstream industries. Our findings reveal several vital points: (1) Direct subsidies significantly enhance Chinese firms’ export participation and volume. These subsidies are positively associated with firm investment and R&D expenditure. (2) Surprisingly, upstream indirect subsidies, particularly those from 1st tier upstream industries, have even larger effects on Chinese exports than direct subsidies. These upstream subsidies contribute significantly to export growth. (3) Both domestic firms and foreign invested enterprises benefit from direct subsidies, but the effect of upstream subsidies varies by firm ownership. (4) Both direct and indirect subsidies are associated with higher export prices and product quality, leading to a lower quality-adjusted price. These export growth and quality upgrading are driven by direct subsidies through increased investment and R&D, and indirect subsidies through intermediate inputs. These results suggest that government support may promote quality upgrading and enhance the global competitiveness of Chinese exports. This paper contributes to the ongoing debate on government subsidy and industrial policies by shedding light on the intricate relationship between subsidies and exports in the context of evolving global value chains.

 報告タイトル：Satellite-Based Vehicle Flow Data to Assess Local Economic Activities

報告概要：Spatially and seasonally granular measures of local economic activities are increasingly required in a variety of economic analyses. We propose using novel vehicle density data obtained from daytime satellite images to quantify the local economic activity involving human and goods traffic flows. Validation exercises show that vehicle density is a good proxy for local economic levels. We then apply our data to evaluate the impact of a new international airport terminal opening in the Philippines on local economies. The results show that the opening of the new terminal has spatially and seasonally heterogeneous impacts that conventional data cannot capture.

 報告タイトル：Cost and Demand Effects of Legal Adult Prostitution on Child Sex Trafficking  (Joint work with Naoshi Doi (Otaru University of Commerce), Masahiro Shoji (University of Tokyo), Kenmei Tsubota (Toyo University), and Md. Sanaul Haque Mondal (East West University))

報告概要：We estimate the impact of legal adult prostitution on child sex trafficking. Using a nationwide survey of child sex workers and plausibly exogenous variations in the location of legal brothels, we show that legalization increases demand for and supply of trafficked children and children who voluntarily engage in prostitution. Counterfactual simulations demonstrate that closing brothels reduces them by 13.5% and 2.7%, respectively, but it deprives legal adult sex workers of their job opportunities. Alternatively, strict screening of trafficking victims in the brothels alone reduces victims by 13.7% without evicting legal workers, but it increases voluntary child sex workers by 2.7%.

 報告タイトル：Valuing Algorithms Over Experts: Evidence from a Stock Price Forecasting Experiment (Joint work with Bolin Mao, Tiffany Tsz Kwan Tse, Wenxin Zhou)

報告概要： This study examined participants’ willingness to pay for stock price forecasts provided by an algorithm, financial experts, and peers. Surprisingly, participants valued algorithmic advice more highly and relied on it as much as expert advice. This preference for algorithms – despite their similar or even lower performance – suggests a shift in perception, particularly among students, toward viewing AI as a reliable and valuable source. However, this “algorithm appreciation” reduced participants’ payoffs, as they overpaid for advice that did not sufficiently enhance performance. These findings underscore the need to develop tools and policies that enable individuals to better assess algorithm performance.

 報告タイトル："From Samurai to Skyscrapers: How Transaction Costs Shape Tokyo” (joint with Junichi Yamasaki and Kentaro Nakajima)

報告概要： Whether transaction costs to assemble or split land can persistently hinder urban land use remains unknown. Constructing a 100 m*100 m-cell-level dataset of central Tokyo from the 19th-century pre-modern era to the 21st-century skyscraper era, we study how initial lot fragmentation has affected urban development. We exploit a plausibly exogenous supply shock of large lots in 1868, the release of local lords’ estates (daimyo yashiki) scattered throughout central Tokyo. Using ordinary least squares and a regression discontinuity design, we find that cells previously used as local lords’ estates have larger lots today, implying that lot size persists through transaction costs. Such cells today see more tall buildings, higher land prices, and higher labor productivity of firms. We also find these effects only in the core area, suggesting higher transaction costs in this area. Finally, the effect of lot size on land prices became positive only after the rise of skyscrapers. This implies that optimal lot size became larger and assembly friction became more salient in the skyscraper age. Overall, transaction costs to change lot size persistently hinder economic activities; in particular, this dominates the potentially large benefits of assembly for skyscraper development in growing urban cores.

 報告タイトル：Extensive and Intensive Margins of Informal Workers’ Public Pension Demand: Evidence from a Mongolian Pension Reform

報告概要： Many developing countries have expanded their pension systems in the last two decades. However, the low coverage of informal workers remains a serious issue. I analyze the impact of a Mongolian large-scale policy that redeemed missing contributions, leading to a relaxation of the contribution requirements. I estimate the price elasticity of public pension demand with respect to money’s worth by a regression kink design approach with administrative data. I find small benefits for young individuals effectively promote participation, and large benefits crowd out additional contributions for certain existing participants. I also find gender-heterogeneous impact mainly driven by different retirement ages.

 報告タイトル：Global Value Chains, Domestic Value Chains, and Comparative Advantage

報告概要： This paper examines how a country’s integration into global value chains (GVCs) affects value chains within a country, domestic value chains (DVCs), and how resulted changes in DVCs alter within-country comparative advantage, using Japan’s inter-regional input-output during the 1960-2005 period. We find that deeper integration into GVCs resulted in a shrink in DVCs in most manufacturing sectors. However, the transport equipment sector is an exception because its GVCs and DVCs expanded. In addition, expanded DVCs strengthened the comparative advantage of the transport equipment sector. However, the same change weakened the comparative advantage of the other manufacturing sectors. We develop a model to understand the mechanisms behind such changes. We find that falling international outsourcing costs in the other manufacturing sectors and productivity growth of intermediate goods in the transport equipment sector explain the empirical results.

報告タイトル：リスク選好の伝染 ー 神経基盤とその発達

報告概要：ローリスク・ローリターンを好むのか？ハイリスク・ハイリターンを好むのか？我々のリスク選好は投資行動やギャンブル依存症など、様々な場面で重要な役割を果たしている。本発表では、「人々のリスク選好は他者の行動を観察することで変化するのか？」について、心理実験及び脳機能計測（functional MRI）を用いて検証した研究を紹介したい。

報告タイトル：リスク選好の伝染 ー 神経基盤とその発達

報告概要：ローリスク・ローリターンを好むのか？ハイリスク・ハイリターンを好むのか？我々のリスク選好は投資行動やギャンブル依存症など、様々な場面で重要な役割を果たしている。本発表では、「人々のリスク選好は他者の行動を観察することで変化するのか？」について、心理実験及び脳機能計測（functional MRI）を用いて検証した研究を紹介したい。

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