national institutions and subnational development in africa we investigate the role of national institutions on subnational african development in a novel framework that accounts both for local geography and cultural genetic traits we exploit the fact that the political boundaries in the eve of african independence partitioned more than two hundred ethnic groups across adjacent countries subjecting similar cultures residing in homogeneous geographic areas to different formal institutions using both a matching type and a spatial regression discontinuity approach we show that differences in countrywide institutional structures across the national border do not explain within ethnicity differences in economic performance as captured by satellite images of light density the average non effect of national institutions on ethnic development masks considerable heterogeneity partially driven by the diminishing role of national institutions in areas further from the capital cities

social culture and economic performance the connection between obtaining higher paying jobs and undertaking some seemingly irrelevant activity is interpreted as social culture in the context of a society trying to adopt a new technology i show that by allowing the firms to give preferential treatment to workers based on some cultural activity the society can partially overcome an informational free riding problem therefore social culture may affect the economic performance by altering the effective production technology of the economy jel p17 z1 what is social culture what is the role of social culture in economic performance in a provocative article kenneth arrow 1971 argued that norms of social behavior including ethical and moral codes are reactions of society to compensate for market failure somewhat surprisingly this idea of the role of social culture has not been further pursued in the literature in this paper i take arrow s viewpoint seriously and construct a simple model to examine the possibility that social culture may alleviate market failure i consider a society that is deciding whether to adopt a new technology three important assumptions are made about the economy first adoption decisions are made by entrepreneurs or firms but the operators of the new technology are workers second the new technology can be successfully operated only when the worker has invested in some imperfectly observable requisite skills and third it is costly for the workers

learning from private and public observations of othersʼ actions we study how a continuum of agents learn about disseminated information by observing others actions every period each agent observes a public and private noisy signal centered around the aggregate action taken by the population the public signal represents an endogenous aggregate variable such as a price or a quantity the private signal represents the information gathered through private communication and local interactions we identify conditions such that the average learning curve is s shaped learning is slow initially intensifies rapidly and finally converges slowly to the truth we show that increasing public information always slows down learning in the long run and under some conditions reduces welfare lastly optimal diffusion of information requires that agents strive to be different agents need to be rewarded for choosing actions away from the population average

the slave trade and the origins of mistrust in africa in a recent study nunn 2008 examines the long term impacts of africa s slave trade he finds that the slave trade which occurred over a period of more than 400 years had a significant negative effect on long term economic development although the article arguably identifies a negative causal relationship between the slave trade and income today the analysis is unable to establish the exact causal mechanisms underlying this reduced form relationship in this article we examine one of the channels through which the slave trade may affect economic development today combining contemporary individual level survey data with historical data on slave shipments by ethnic group we ask whether the slave trade caused a culture of mistrust to develop within africa initially slaves were captured primarily through state organized raids and warfare but as the trade progressed the environment of ubiquitous insecurity caused individuals to turn on others including friends and family members and to kidnap trick and sell each other into slavery sigismund wilhelm koelle 1854 p e h hair 1965 charles piot 1996 we hypothesize that in this environment a culture of mistrust may have evolved which may persist to this day we show that current differences in trust levels within africa can be traced back to the transatlantic and indian ocean slave trades combining contemporary individual level survey data with historical data on slave shipments by ethnic group we find that individuals whose ancestors were heavily raided during the slave trade are less trusting today evidence from a variety of identification strategies suggests that the relationship is causal examining causal mechanisms we show that most of the impact of the slave trade is through factors that are internal to the individual such as cultural norms beliefs and values jel j15 n57 z13

informative advertising with differentiated products in this paper we study the role of promotional expenditures by sellers in a model of product differentiation advertising conveys full and accurate information about the characteristics of products heterogeneous consumers who have no source of information other than advertisements seek to purchase the products that best fit their needs despite the roles played by advertising in improving the matching of products and consumers and in increasing the elasticity of demand faced by each firm we find that the market determined levels of advertising are excessive given the extent of diversity in the market we derive a promotional equilibrium based on a specific information transmission technology paying explicit attention to the structure of consumer information and its impact on firms demand curves this allows us to study the effects of changes in the advertising technology including an increased ability to target messages to specific groups of consumers on the equilibrium in the product market we find that decreased advertising costs may reduce profits by increasing the severity of price competition

inherited trust and growth this paper develops a new method to uncover the causal effect of trust on economic growth by focusing on the inherited component of trust and its time variation we show that inherited trust of descendants of us immigrants is sig nificantly influenced by the country of origin and the timing of arrival of their forebears we thus use the inherited trust of descendants of us immigrants as a time varying measure of inherited trust in their country of origin this strategy allows to identify the sizeable causal impact of inherited trust on worldwide growth during the twentieth century by controlling for country fixed effects jel n11 n12 n31 n32 o47 z13

consumer search with observational learning this article studies observational learning in a consumer search environment consumers observe the purchasing decision of a predecessor with similar preferences consumers rationally emulate by initiating their search at the firm from which their predecessor purchased free riding on search effort and reacting less to price changes prices are nonmonotone in search costs and may be as low as marginal costs we discuss several extensions and show that the effect of emulation on prices is stronger when i the number of firms increases ii consumers first visits are more elastic with respect to market shares and iii prices are adjusted more frequently

learning by doing and learning from others human capital and technical change in agriculture household level panel data from a nationally representative sample of rural indian households describing the adoption and profitability of high yielding seed varieties hyvs associated with the green revolution are used to test the implications of a model incorporating learning by doing and learning spillovers the estimates indicate that i imperfect knowledge about the management of the new seeds was a significant barrier to adoption ii this barrier diminished as farmer experience with the new technologies increased iii own experience and neighbors experience with hyvs significantly increased hyv profitability and iv farmers do not fully incorporate the village returns to learning in making adoption decisions

word of mouth communication and social learning this paper studies the way that word of mouth communication aggregates the information of individual agents we find that the structure of the communication process determines whether all agents end up making identical choices with less communication making this conformity more likely despite the players naive decision rules and the stochastic decision environment word of mouth communication may lead all players to adopt the action that is on average superior these socially efficient outcomes tend to occur when each agent samples only a few others i introduction economic agents must often make decisions without knowing the costs and benefits of the possible choices given the frequency with which such situations arise it is understandable that agents often choose not to perform studies or experiments but instead rely on whatever information they have obtained via casual word of mouth communication reliance on this sort of easily obtained information appears to be common in circumstances ranging from consumers choosing restaurants or auto mechanics to business managers evaluating alternative organizational structures this paper studies two related environments in arguing that individuals reliance on word of mouth communication has interesting implications for their aggregate behavior first motivated by the diffusion of new technologies we consider a choice between two competing products with unequal qualities or payoffs and show that the structure of communication is important in determining whether the population as a whole is likely to learn to use the superior product second we consider a choice between two products or practices that are equally good and ask whether consumers are likely to herd onto a single choice or whether diversity will obtain even in the long run we explore the implications of word of mouth communication in a simple nonstrategic environment there is a large population of identical players each of whom repeatedly chooses between two possible actions each player s payoff is determined by his own

experimentation in markets we present a model of entry and exit with bayesian learning and price competition a new product of initially unknown quality is introduced in the market and purchases of the product yield information on its true quality we assume that the performance of the new product is publicly observable as agents learn from the experiments of others informational externalities arise we determine the markov perfect equilibrium prices and allocations in a single market the combination of the informational externalities among the buyers and the strategic pricing by the sellers results in excessive experimentation if the new product is launched in many distinct markets the path of sales converges to the efficient path in the limit as the number of markets grows in multi agent learning situations informational externalities may reduce the number of experiments undertaken below the socially efficient level as buyers choose among new experience goods or firms decide whether to adopt a new technology the availability of information from others decisions gives rise to a free rider problem rather than perform a costly experiment herself a buyer may opt to wait and see how the market evaluates the new product in this paper we develop a simple market model of experimentation and analyse the informational effects in a model with buyers and sellers in contrast to the one sided experimentation problems we find that equilibrium experimentation often exceeds the pareto optimal level in two sided models the first model we consider is a dynamic duopoly in continuous time with homogeneous buyers two firms with differentiated products engage in price competition over time one product has a known value while the other is new and its true value is initially uncertain to all the parties in the model the value of the product is determined by the quality of the match between consumer preferences and product characteristics additional information is acquired only through repeat purchases in each period buyers observe a noisy signal of the true value of the product we assume that all signals are publicly observable and that all uncertainty is about a common value component with this assumption all buyers and sellers condition their behaviour on the same information and we can abstract from individual differences in past observations this is justified in economic situations where public data on other buyers choices is available and informative for example when choosing among providers of communication or transportation services such as mail delivery firms or airlines it is reasonable to rely on consumer reports and other published data in addition to one s private experience we also show that our model has an alternative interpretation as one where a flow of buyers make a once and

pulsation in a competitive model of advertising firm s cost interaction the literature reveals contradiction between theoretical results superiority of uniform policy under a concave advertising response function and empirical results concavity of the advertising response function and the superiority of a pulsation policy to reconcile the above difference this paper offers a resolution based on 1 the concavity of the advertising response function 2 the convexity of the firm s cost function and 3 over advertising the resolution is reached upon maximizing the net profit per unit time over the infinite planning horizon subject to an exogenous advertising budget constraint theoretical results for monopolistic markets are found mostly generalized to competitive markets a numerical example is introduced to gain more insight into the theoretical findings and an approach is introduced and implemented to empirically assess the shape of a firm s cost function and the advertising policy to be employed

the financial rewards of new product introductions in the personal computer industry based on data from firms in the personal computer industry we study the effect of new product introductions on three key drivers of firm value profit rate profit rate persistence and firm size as reflected in asset growth consistent with our theoretical development we find that new product introductions influence profit rate and size however we find no effect on profit rate persistence interestingly we also find that the effect of new product introductions on profit rate stems from a reduction in selling and general administrative expenditure intensity rather than through an increase in gross operating return notably firms decrease their advertising intensity in the wake of a new product introduction firm profitability in this industry apparently benefits from new product introductions because new products need less marketing support than older products

work environment and individual background explaining regional shirking differentials in a large italian firm the prevalence of shirking within a large italian bank appears to be characterized by significant regional differentials in particular absenteeism and misconduct episodes are substantially more prevalent in the south we consider a number of potential explanations for this fact different individual backgrounds group interaction effects sorting of workers across regions differences in local attributes different hiring policies and discrimination against southern workers our analysis suggests that individual backgrounds group interaction effects and sorting effects contribute to explaining the north south shirking differential none of the other explanations appears to be of first order importance i introduction whether individual behavior is determined by group interactions or by individual background is undoubtedly a fundamental question for the social sciences this question presented itself forcefully when we stumbled onto the following piece of evidence there appear to be significant regional differentials in the prevalence of shirking among the employees of a large italian bank in particular absenteeism and misconduct episodes are considerably more frequent in the southern branches of the bank in this paper we examine several potential explanations for this fact first individual preferences for shirking versus working may differ according to one s region of hirth we will refer to this hj othesis as one of different individual hackgrounds the second possibility is one of locational sorting low shirking types may tend to migrate to the north high shirking types may tend to migrate to the south or hoth third the northern and southern

history institutions and economic performance the legacy of colonial land tenure systems in india we analyze the colonial land revenue institutions set up by the british in india and show that differences in historical property rights institutions lead to sustained differences in economic outcomes areas in which proprietary rights in land were historically given to landlords have significantly lower agricultural investments and productivity in the post independence period than areas in which these rights were given to the cultivators these areas also have significantly lower investments in health and education these differences are not driven by omitted variables or endogeneity problems they probably arise because differences in historical institutions lead to very different policy choices

the long term effects of africa s slave trades can part of africa s current underdevelopment be explained by its slave trades to explore this question i use data from shipping records and historical documents reporting slave ethnicities to construct estimates of the number of slaves exported from each country during africa s slave trades i find a robust negative relationship between the number of slaves exported from a country and current economic performance to better understand if the relationship is causal i examine the historical evidence on selection into the slave trades and use instrumental variables together the evidence suggests that the slave trades have had an adverse effect on economic development

selection on observed and unobserved variables assessing the effectiveness of catholic schools in this paper we measure the effect of catholic high school attendance on educational attainment and test scores because we do not have a good instrumental variable for catholic school attendance we develop new estimation methods based on the idea that the amount of selection on the observed explanatory variables in a model provides a guide to the amount of selection on the unobservables we also propose an informal way to assess selectivity bias based on measuring the ratio of selection on unobservables to selection on observables that would be required if one is to attribute the entire effect of catholic school attendance to selection bias we use our methods to estimate the effect of attending a catholic high school on a variety of outcomes our main conclusion is that catholic high schools substantially increase the probability of graduating from high school and more tentatively attending college we find little evidence of an effect on test scores

colonialism and modern income islands as natural experiments abstract using a new database of islands throughout the atlantic pacific and indian oceans we find a robust positive relationship between the number of years spent as a european colony and current gdp per capita we argue that the nature of discovery and colonization of islands provides random variation in the length and type of colonial experience we instrument for length of colonization using variation in prevailing wind patterns we argue that wind speed and direction had a significant effect on historical colonial rule but do not have a direct effect on gdp today the data also suggest that years as a colony after 1700 are more beneficial than earlier years we also find a discernable pecking order among the colonial powers with years under u s british french and dutch rule having more beneficial effects than spanish or portuguese rule our finding of a strong connection between modern income and years of colonization is conditional on being colonized at all since each of the islands in our da

learning and strategic pricing we consider the situation where a single consumer buys a stream of goods from different sellers over time the true value of each seller s product to the buyer is initially unknown additional information can be gained only by experimentation for exogeneously given prices the buyer s problem is a multi armed bandit problem the innovation in this paper is to endogenize the cost of experimentation to the consumer by allowing for price competition between the sellers the role of prices is then to allocate intertemporally the costs and benefits of learning between buyers and sellers we examine how strategic aspects of the oligopoly model interact with the learning process all markov perfect equilibria mpe are efficient we identify an equilibrium which besides its unique robustness properties has a strikingly simple seemingly myopic pricing rule prices below marginal cost emerge naturally to sustain experimentation intertemporal exchange of the gains of learning is necessary to support efficient experimentation we analyze the asymptotic behavior of the equilibria

development and social capital abstract this paper examines social capital and its relation with economic development we focus on the role that interpersonal relationships play in social exchange whether through the market or through the provision of public goods by facilitating search and trust social capital can increase the efficiency of social exchange where formal institutions are weak but the benefits from social capital are likely to be unequally distributed given these features documenting empirically the benefits of social capital is complicated by the presence of negative and positive externalities and by the existence of leadership and group effects lessons for development policy are drawn at the end

design innovation and fashion cycles a model of fashion cycles is developed in which designs are used as a signaling device in a dating game a monopolist periodically creates a new design over time the price of the design falls as it spreads across the population once sufficiently many consumers own the design it is profitable to create a new design and thereby render the old design obsolete this paper gives conditions under which all consumers would be better off by banning the use of fashion competition among designers may lead to less frequent changes in fashion and to higher prices than monopoly copyright 1995 by american economic association

in search of homo economicus behavioral experiments in 15 small scale societies we can summarize our results as follows first the canonical model is not supported in any society studied second there is considerably more behavioral variability across groups than had been found in previous cross cultural research and the canonical model fails in a wider variety of ways than in previous experiments third group level differences in economic organization and the degree of market integration explain a substantial portion of the behavioral variation across societies the higher the degree of market integration and the higher the payoffs to cooperation the greater the level of cooperation in experimental games fourth individual level economic and demographic variables do not explain behavior either within or across groups fifth behavior in the experiments is generally consistent with economic patterns of everyday life in these societies

regulation and distrust in a cross section of countries government regulation is strongly negatively correlated with social capital we document this correlation and present a model explaining it in the model distrust creates public demand for regulation while regulation in turn discourages social capital accumulation leading to multiple equilibria a key implication of the model is that individuals in low trust countries want more government intervention even though the government is corrupt we test this and other implications of the model using country and individual level data on social capital and beliefs about government s role as well as on changes in beliefs and in trust during the transition from socialism

war and local collective action in sierra leone abstract we study the brutal 1991 2002 sierra leone civil war using nationally representative household data on conflict experiences postwar economic outcomes local politics and collective action individuals whose households directly experienced more intense war violence are robustly more likely to attend community meetings more likely to join local political and community groups and more likely to vote tests using prewar controls and alternative samples suggest that selection into victimization is unlikely to be driving the results more speculatively the findings could help partially explain the rapid postwar political and economic recoveries observed in sierra leone and after several other recent african civil wars

social norms savings behavior and growth we argue that many goods and decisions are not allocated or made through markets we interpret an agent s status as a ranking device that determines how well he or she fares in the nonmarket sector the existence of a nonmarket sector can endogenously generate a concern for relative position in for example the income distribution so that higher income implies higher status moreover it can naturally yield multiple equilibria it is thus possible to explain differences in growth rates across countries without recourse to differences in underlying preferences technologies or endowments different social organizations lead to different reduced form preferences which lead to different growth rates

narrow and scientific replication of the slave trade and the origins of mistrust in africa summary nunn and wantchekon 2011 argue that slave trades led to a culture of mistrust in africa they regress self reported trust from the 2005 afrobarometer surveys on ethnicity specific historic slave exports individuals from ethnic groups that experienced high levels of slave exports are less trusting causality is demonstrated by instrumenting slave exports using the historic distance of each ethnic group to the coast our narrow replication yields identical results the scientific replication repeats the analysis with afrobarometer survey data from 2008 which includes two new countries and more ethnic groups our replication confirms the results of nunn and wantchekon copyright 2012 john wiley sons ltd

climate and the slave trade african societies exported more slaves in colder years lower temperatures reduced mortality and raised agricultural yields lowering slave supply costs our results help explain african participation in the slave trade which predicts adverse outcomes today we use an annual panel of african temperatures and port level slave exports to show that exports declined when local temperatures were warmer than normal this result is strongest where african ecosystems are least resilient to climate change cold weather shocks at the peak of the slave trade predict lower economic activity today we support our interpretation using the histories of whydah benguela and mozambique

product servicing for lifespan extension and sustainable consumption an optimization approach abstract sustainable consumption has been defined as the consumption of goods and services that meet basic needs and quality of life without jeopardizing the needs of future generations oecd 2002 lifespan extension of durable products underpins sustainable consumption this paper describes a novel approach to extend product lifespans by using product servicing that conceptualizes the interactions of a producer a policy maker and multiple consumer segments having different price demand relationships we propose a multi period mathematical optimization model that maximizes the producer s profit while optimizing the prices of different servicing options production quantities and inventory levels a computational study elicits several insights about how the optimal production or alternatively consumption quantities are affected by the introduction of product servicing and the effects of various product characteristics and government incentive or penalty levels on producer s profitability and on product servicing decisions we conclude that quantitative optimization models are useful for evaluating the impacts of different regulatory policies assessing the benefits of offering product servicing options and investing in design for durability and serviceability

strategic firms and endogenous consumer emulation better informed consumers may be treated preferentially by firms since their consumption serves as a quality signal for other customers for normal goods this results in wealthy individuals being treated better than poor individuals we investigate this phenomenon in an equilibrium model of social learning with heterogeneous consumers and firms that act strategically consumers search for high quality firms and condition their choices on observed actions of other consumers when they observe consumers who are more likely to have identified a high quality firm uninformed individuals will optimally emulate those consumers one group of consumers arises endogenously as leaders whose consumption behavior is emulated follow on sales induce firms to give preferential treatment to these lead consumers which reinforces their learning

the unintended consequence of an export ban evidence from benin s shrimp sector summary the inability of benin to comply with eu standards led to a ban on its shrimp exports we show that the ban had a negative impact on the income of fishmongers and fishermen in the short run but also several years after it was lifted the impact persisted because exports to the eu did not revive and the local shrimp demand could not fully compensate for the loss of the eu market a small number of local actors coped with the ban by moving out of the sector but the large majority were locked in the local fishery sector

the effect of technological knowledge assets on performance the innovative choice in spanish firms abstract the aim of this article is to examine the relationship between technological knowledge assets tkas and performance in the light of making the innovative choice that involves short term costs of acquiring or generating the assets but aims at longer term benefits through innovation to that end a study of 1267 industrial firms in spain was carried out over a period of 5 years 1998 2002 the results show that tkas have a positive indirect effect on financial performance mediated through innovation they also reveal that tkas have a negative direct effect on performance except licences thus the combined effect of tkas on performance urges the need for innovation to obtain a positive payoff

information revelation in a market with pairwise meetings the paper presents a simple pairwise meetings model of trade the new feature is that agents have asymmetric information about the true state of the world the focus is on the transmission of the information through the process of trade the qualitative question is to what extent is the information revealed to uninformed agents through the trading process when the market is in some sense frictionless in particular does the decentralized process give rise to full revelation results as derived by the literature on rational expectations for centralized and competitive environments in the context of the model of this paper it turns out that the information is not fully revealed to uninformed agents even when the market is in some sense approximately frictionless

product innovation product market competition and persistent profitability in the u s pharmaceutical industry increasingly strategy scholars are exploring the relationships between innovation competition and the persistence of superior profits sustained high profitability may result when a firm repeatedly introduces valuable innovations that service previously unmet consumer demands while the returns to the firm from each innovation may erode over time innovation ensures that overall the firm maintains a high performance position at the same time sustained high profitability may also accrue to firms that innovate less often but effectively avoid the competition that otherwise erodes high returns this paper elaborates these relationships before presenting an empirical analysis of the effects of differential innovative propensities and differential rates of competition on pharmaceutical firms abilities to sustain profit outcomes that are above those earned by competing firms the analysis which is situated within the u s pharmaceutical industry finds support for the expected relationship between high innovative propensity and sustained superior profitability but no support for a link between persistence and the ability to avoid competition copyright 1999 john wiley sons ltd

keeping it in the family lineage organization and the scope of trust in sub saharan africa we present evidence that the traditional structure of society is an important determinant of the scope of trust today within africa individuals belonging to ethnic groups that organized society using segmentary lineages exhibit a more limited scope of trust measured by the gap between trust in relatives and trust in non relatives this trust gap arises because of lower levels of trust in non relatives and not higher levels of trust in relatives a causal interpretation of these correlations is supported by the fact that the effects are primarily found in rural areas where these forms of organization are still prevalent

r d partnership portfolios and the inflow of technological knowledge this article links research on parallel search and joint r d to contribute a portfolio perspective to the study of knowledge flows within interfirm r d partnerships in a longitudinal analysis of firms engaged in r d partnerships relating to information technology between 1975 and 1999 we show that the size of a firm s r d partnership portfolio and its share of novel partners both have an inverted u shaped effect on the inflow of technological knowledge from the firm s r d partners we also show how these direct effects vary as a function of the level of technological uncertainty within the portfolio

learning from trades i study stationary cut off strategy equilibria of a dynamic market model where buyers sample sellers sequentially from an unknown distribution buyers learn about the distribution from the sampled sellers and a trade signal the trade signal reveals whether a randomly chosen seller traded yesterday observing a trade as opposed to no trade is good news about the distribution buyers who observe a trade use a higher cut off than buyers who observe no trade despite buyers learning from sampled sellers that puts a countervailing pressure on the cut offs the trade signal may reduce market efficiency while an appropriate exogenous signal increases efficiency