the evolution of time preference with aggregate uncertainty we examine the evolutionary foundations of intertemporal preferences when all the risk affecting survival and reproduction is idiosyncratic evolution selects for agents who maximize the discounted sum of expected utility discounting at the sum of the population growth rate and the mortality rate aggregate uncertainty concerning survival rates leads to discount rates that exceed the sum of population growth rate and death rate and can push agents away from exponential discounting

the household response to persistent natural disasters evidence from bangladesh we examine the short run economic impacts of recurrent flooding on bangladeshi households surveyed in 2000 2005 and 2010 in 2010 household income and expenditure survey hies households answered a set of questions on whether they were affected by flood and its likely impacts we identify two treatment affected groups by using the self reported data and historical rainfall data based flood risk index we estimate a difference indifference did model to quantify the impacts on income expenditure asset and labour market outcomes and further extend our analysis to different income and expenditure brackets overall we find robust evidence of negative impacts on agricultural income and expenditure intriguingly the extreme poor i e the bottom 15th quintile experience significant positive impacts on agricultural income in the self reported treatment case

environmental shocks and sustainability in microfinance evidence from the great famine of ireland i study the effects of a major environmental shock on microfinance lending by analyzing the irish loan funds during the great famine of ireland i find that funds in districts worse affected by bli

microfinance and poverty evidence using panel data from bangladesh micro finance supports mainly informal activities that often have low market demand it may be thus hypothesized that the aggregate poverty impact of micro finance in an economy with low economic growth is modest or nonexistent the observed borrower level poverty impact is then a result of income redistribution or short run income generation the author addresses these questions using household level panel data from bangladesh the findings confirm that micro finance benefits the poorest and has sustained impact in reducing poverty among program participants it also has positive spillover impact reducing poverty at the village level but the effect is more pronounced in reducing extreme rather than moderate poverty

the evolutionary theory of time preferences and intergenerational transfers at each age an organism produces energy by foraging and allocates this energy among reproduction survival growth and intergenerational transfers we characterize the optimal set of allocation decisions that maximizes fitness time preference the discount rate is derived from the marginal rate of substitution between energy obtained at two different times or ages holding fitness constant time preference varies with age in different ways depending on whether an individual is immature or mature and during the transition between these stages we conclude that time preference and discount rates are likely to be u shaped across age

microfinance its impact outreach and sustainability summary this symposium brings together recent empirical contributions with respect to a number of related and highly relevant issues on the economics of microfinance in particular the contributions provide answers to the following two main questions 1 does microfinance have an impact on the social and economic situation of the poor in developing nations and 2 are microfinance institutions sustainable in the long term and is there a trade off between sustainability and outreach

a biological theory of social discounting we consider a growth model in which intergenerational transfers are made via stocks of private and public capital private capital is the outcome of individuals private savings while decisions regarding public capital are made collectively we hypothesize that private saving choices evolve through individual selection while public saving decisions are the result of group selection the main result of the paper is that the equilibrium rate of return to private capital is at least 2 3 percent more than the rate of return to public capital in other words social choices involving intertemporal trade offs exhibit much more patience than individual choices do jel d11 d71 d91 h43 policy issues often involve intergenerational trade offs one highly publicized and polarizing example concerns the appropriate response to global warming while nordhaus 1994 concluded that there was no need to enact draconian policies to reduce co 2 emissions immediately stern 2006 insisted that the situation was in fact dire the difference in position can be attributed almost exclusively to the rates of time preference assumed by these two authors nordhaus used a few percent based on estimates deriving from private economic behavior while stern essentially set it equal to zero on the basis of a philosophical stance it then becomes clear that co 2 emissions should be taken seriously if for some reason private rates of time preference are too high when applied to public decisions since such decisions should then be made on the basis of a lower rate 1

time preference and life cycle consumption with endogenous survival we provide a structural theory of time preference and derive a functional form of intertemporal preferences by postulating that individuals make their life cycle consumption choices as if to maximize expected lifetime this yields a nontime separable expected utility representation where the inverse of the coefficient of intertemporal substitution exceeds the coefficient of relative risk aversion the rate of time preference depends on the inverse of expected remaining lifetime and the effect of age on the productivity of consumption in affecting health the preference formulation is applied in a standard intertemporal consumption model to illustrate the implied life cycle consumption choices

the evolution of intertemporal preferences where do preferences come from what determines their properties though traditionally reluctant to ask such questions economists have recently turned to evolutionary models for answers we focus on intertemporal preferences here arising out of the evolutionary implications of different reproductive strategies or life histories an agent s life history specifies the agent s number and timing and in a richer model quality of offspring evolution will select the life history that maximizes the growth rate of the associated group of individuals we begin with the simplest possible biological life history that of a semelparous agent that if it survives a fixed number of years reproduces and then dies we show the evolutionary criterion for success in this case entails hyperbolic time discounting of the log of the number of offspring produced the rate of time preference is a function of age however not of time relative to the present and there are no preference reversals in the sense of behavioral economics at the same time the optimal strategy maximizes the exponentially discounted number of offspring provided we discount at the sum of the death rate and the maximal growth rate conventional discounting thus suffices to induce optimal choices from the agent more generally if the animal is iteroparous that is has a nondegenerate profile of offspring we show the evolutionary indifference curves over offspring of various ages are hyperplanes that are not parallel but tilt to reflect greater impatience as the growth rate increases there is no additively separable function of the age profile of expected offspring that is globally equivalent to this basic biological growth rate the evolution of intertemporal preferences

community based risk management arrangements a review summary risk and its consequences pose a formidable threat to poverty reduction efforts this article reviews a plethora of community based risk management arrangements across the developing world these types of arrangements are garnering greater interest in light of the growing recognition of the relative prominence of household or individual specific idiosyncratic risk as well as the increasing shift towards community based development funding the article discusses potential advantages such as targeting cost and informational and disadvantages such as exclusion and inability to manage correlated risk of these arrangements and their implications for the design of community based social protection programs and policies

does religion constrain the risky sex behaviour associated with hiv aids this article examines the likely effectiveness of public health interventions designed to change the risky sexual behaviour associated with human immunodeficiency virus acquired immune deficiency syndrome hiv aids by faith based organizations fbos we utilize data from the general social survey gss to estimate an economic model of sexual behaviour our theoretical approach proceeds by rationalizing on evolutionary grounds the existence of sexual activity in individual preference functions with unobservable costs imposed by religious beliefs and participation given the objective of utility maximization we justify the existence of demand functions for sexual activity that generate empirically testable hypotheses about the effects of religion and religious participation on risky sexual activity our results suggest that at least in the case of heterosexuals fbos can indeed influence the risky sexual behaviour that is associated with the transmission of hiv aids

does contingent repayment in microfinance help the poor during natural disasters abstract microfinances in bangladesh introduced a contingent repayment system beginning in 2002 which allowed rescheduling of savings and installments during natural disasters for affected members this paper is one of the first attempts to evaluate the system employing a unique dataset in using evidence from a flood in 2004 the author found that rescheduling plays the role of a safety net by decreasing the probability that people skip meals during negative shocks by 5 1 per cent this effect is even higher on the landless and females this study attempts to contribute to the issue regarding the poverty reduction effect of microfinances

public policy markets and household coping strategies in bangladesh avoiding a food security crisis following the 1998 floods abstract at their peak the 1998 floods covered two thirds of bangladesh causing severe damage to the major rice crop and threatening the food security of tens of millions of households in this paper we first highlight the contribution of government policy interventions including trade liberalization in the early 1990s to stabilization of rice markets during and after the flood then using a panel data set covering 750 households in three rounds over a 13 month period we analyze impacts of the flood on household assets consumption and nutritional outcomes finally we present empirical estimates of the contribution of rice market stabilization and government transfers to household food consumption

the evolution of preferences and competition a rationalization of veblen s theory of invidious comparisons we examine how preferences evolve by natural selection in a competitive environment similar to that characterizing much of our evolutionary past we find that the evolutionarily stable preferences in this context exhibit a concern not only for absolute payoffs but also for relative payoffs and that this intensifies the degree of competition relative to what obtains when players consider only absolute payoffs we argue that this has consequences for the equilibrium population size we argue that the premise of this analysis is consistent with the available anthropological evidence and that the prediction is broadly consistent with the findings of experimental game theory

on the growth maximizing distribution of income this paper presents an unconventional argument based on population growth to bolster marginal productivity theory there is an economy with a single output produced from a number of different types of labor each type of labor is reproduced from that type itself and from the amount of the output devoted to it under some income distributional norm any norm which fails to induce convergence to maximal balanced growth is growth dominated in that the population and income it induces can be overwhelmed eventually on the maximal balanced growth path the norm divides output according to marginal productivity copyright 1997 by economics department of the university of pennsylvania and the osaka university institute of social and economic research association

evolution of preferences we endogenize preferences using the indirect evolutionary approach individuals are randomly matched to play a two person game individual subjective preferences determine their behaviour and may differ from the actual objective pay offs that determine fitness matched individuals may observe the opponents preferences perfectly not at all or with some in between probability when preferences are observable a stable outcome must be efficient when they are not observable a stable outcome must be a nash equilibrium and all strict equilibria are stable we show that for pure strategy outcomes these conclusions are robust to allowing almost perfect and almost no observability with the notable exception that inefficient strict equilibria may fail to be stable with any arbitrarily small degree of observability despite being stable with no observability

a theory of time preference grant a taylor this article proposes that people generally prefer present consumption to future consumption because their expected utility from consumption eventually falls as their mental and physical abilities eventually decline with age moreover contrary to the ubiquitous intertemporal formulation with a constant rate of time preference and contrary to three recent theories of time preference that predict decreasing discounting as people age this article asserts that discounting increases over the life cycle this hypothesis is supported by data from the panel study of income dynamics as well as evidence from numerous previous studies jel d91 1 introduction despite the almost universal assumption of time preference in models of intertemporal choice an adequate explanation of why people discount the future has not been provided 1 olsen and bailey 1981 make a convincing case for positive time preference by contradiction i e without time preference models of intertemporal choice do not yield predictions consistent with observed behavior but they do not explain why individuals would rationally discount the future 2 three recent studies have attempted to provide the explanation rogers 1994 argues that societies that discount the future at a rate of about 2 will be the long run survivors in an evolutionary fitness situation 3 posner 1995 argues that discounting occurs because individuals have multiple selves that is people are weighting their present consumption far more heavily than their future consumption because the present self and the future self are in some meaningful sense separate persons 92 becker and mulligan 1997 argue that discounting occurs because of a rational defective recognition of future utilities 730 but as will be shown these three theories are inconsistent with empirical evidence on consumption over the life cycle in at least one important aspect this article constructs and empirically supports a new theory of time preference the hypothesis is that people do not have an intrinsic preference for present consumption relative to future consumption instead the instantaneous utility function also known as the felicity function is expected to vary with age just as people s physical and mental abilities vary with age in other words the ability to enjoy consumption eventually deteriorates over the life cycle along with other abilities this life cycle view of the expected utility function causes people to rationally devalue consumption in periods of low expected felicity that is discount future consumption perhaps this is what is meant by the cliche don t wait until you are too old to enjoy it moreover this causes individuals implicit discount rates to vary systematically with age 4 in fact this provides the testable implication of the theory the standard specification of intertemporal preferences holds the discount rate constant over th e life cycle 5 to be more precise in the early stage of the life cycle the capacity to enjoy consumption may be expected to rise hence a young individual s discount rate may be negative figure 1 illustrates this possibility with a hypothetical adult life cycle marginal felicity function for a given level of consumption u sub c c a c denotes consumption and a denotes age and its corresponding discount rate function rho a the vast majority of wealth is held by older people that is those in the declining stage of their abilities thus the preference for present consumption over future consumption appears to hold in the aggregate this view of intertemporal preferences may at first seem inconsistent with practically all dynamic analyses which are based on the notion of stationary utility on further consideration however the hypothesis is quite consistent with modern consumer theory since becker 1965 it has been widely accepted that households derive utility from commodities that are produced with market goods combined with household time and skills i

the role of intergenerational transfers in aggregate capital accumulation this paper uses historical u s data to directly estimate the contribution of intergenerational transfers to aggregate capital accumulation the evidence presented indicates that intergenerational transfers account for the vast majority of aggregate u s capital formation only a negligible fraction of actual capital accumulation can be traced to life cycle or hump savings a major difference between this study and previous investigations of this issue is the use of more accurate longitudinal age earnings and age consumption profiles these profiles are simply too flat to generate substantial life cycle savings this paper suggests the importance of and need for substantially greater research and data collection on intergenerational transfers life cycle models of savings that emphasize savings for retirement as the dominant form of capital accumulation should give way to models that illuminate the determinants of intergenerational transfers

coping with flood role of institutions in bangladesh the article examines the coping strategies that rural households adopted during the 1998 flood in bangladesh and assesses its impact on household welfare including coping and vulnerability both vulnerability and poverty have in general declined in bangladesh yet 60 of rural households adopted a coping of one type or another and about half of rural households were both vulnerable as well as found to adopt any coping mechanism during the 1998 flood household level panel data analysis confirms that the flood reduced both consumption and asset and forced many households to adopt some coping mechanisms to mitigate the adverse effects of flood consequently natural disaster such as flooding increases households vulnerability to poverty however post flood bumper crop production and operation of targeted programs such as microfinance helped compensate the losses of flood

effects of microcredit and other loans on female empowerment in bangladesh the borrower s gender influences intra household resource allocation this article examines microcredit s effectiveness in empowering women borrowers in rural bangladesh it does so by examining how gender specific borrowing activities influence household expenditures which are either specifically of interest to men or women and by examining the effects of all loans rather than only those provided by microcredit organizations the article uses a quasi experimental design to identify the effects of borrowing by men and women by using an original combination of panel data and instrumental variables on subsamples of the surveyed population it finds that the borrower s gender affects how households allocate their resources to different expenditure items and assets that are valued differently by men and women in all the findings suggest that providing greater credit access to women may improve their household bargaining positions

how trade saved humanity from biological exclusion an economic theory of neanderthal extinction abstract one of the great puzzles in science concerns the rise of early modern humans and the fall of neanderthals a number of theories exist and many support the biological principle of competitive exclusion but the evidence for such mechanistic theories in which biology is destiny is limited in response this paper develops a behavioral model of neanderthal extinction we show how the endogenous division of labor and subsequent trading among early modern humans could have helped them to overcome potential biological deficiencies we discuss the relation between economics and natural selection and show how trade may partially offset natural selection

intra household resource allocation under negative income shock a natural experiment summary using households from coastal districts in bangladesh as a case and applying the difference in difference estimation method this paper demonstrates a gender differentiated outcome of negative income shocks for education expenditures of households the cyclonic disaster that reduced crop income substantially increased the demand for labor as well as wages for rebuilding damaged farms this in turn increased the opportunity costs of boys schooling as reconstruction is a male friendly sector consequently parents withdrew their sons from school and engaged them in their households repair work and or in wage earning activities however girls schooling expenditure was unchanged in the affected farm and non farm households

cultural constraints on innovation based growth to what extent does the cultural composition of a society impose a constraint on its long run growth potential we study this question in the context of an innovation based model of growth where cultural attitudes are endogenously transmitted from one generation to the next focusing on attitudes regarding patience we analyze the two way interaction between economic growth and the intergenerational transmission of patience exploiting this interaction we compare the long run growth performance of a culturally heterogeneous society where patience is initially underrepresented in the population with a culturally homogeneous society where all agents are perfectly patient our main result is that in the absence of any intrinsic preferences of patient parents to transmit their attitudes to their children the development paths of the two societies are bound to diverge with the culturally heterogeneous society experiencing lower growth rates yet if patient parents ceteris paribus prefer their children to be patient like them we show that the two societies can in the long run grow at the same rate jel d91 e24 o30 o40 z10

government policy network externalities and mobile telecommunication services evidence from oecd countries this article analyses the effect of government policy on the diffusion of mobile telecommunication services in member countries of the organization for economic cooperation and development oecd specifically we examine how the competition in and standard policies of each country affect cellular diffusion through interactions with positive and negative network externalities the empirical analysis shows that significant network externality effects exist in a cellular market although the positive effects dominate the negative effects initially the negative network externality effects become larger and outweigh the positive externality effects after a certain level of diffusion rate has been achieved in particular a single standard policy and the speed of technological innovation combined with the previous penetration rate generate a positive network externality on the diffusion of mobile telecommunications however a competition policy that solely increases the rate of new subscriptions does not gen

the origin of utility sexual selection and conspicuous consumption abstract this paper proposes an explanation for the universal human desire for increasing consumption and the associated propensity to trade survival opportunity off conspicuous consumption i argue that this desire was moulded in evolutionary times by a mechanism known to biologists as sexual selection whereby an observable trait conspicuous consumption in this case is used by members of one sex to signal their unobservable characteristics valuable to members of the opposite sex it then shows that the standard economics problem of utility maximisation is formally equivalent to the standard biology problem of the maximisation of individual fitness the ability to pass genes to future generations and thus establishes a rigorous theoretical foundation for including conspicuous consumption in the utility function

malthusian selection of preferences the authors study natural selection of preferences using a golden age model with endogenous population in equilibrium all agents have preferences with maximum biological fitness given resource constraints and total population is the maximum the environment can sustain naturally selected agents follow the golden rule acting as if they maximize the undiscounted sum of per capita felicities of current and future generations selected preferences and hence work saving consumption and population density vary predictably with environmental differences copyright 1990 by american economic association

malthus was right after all poor relief and birth rates in southeastern england the payment of child allowances to laborers with large families was widespread in early nineteenth century england this paper tests thomas malthus s hypothesis that child allowances caused the birth rate to increase a cross sectional regression model is estimated to explain variations in birth rates across parishes in 1826 30 birth rates are found to be related to child allowances income and the availability of housing as malthus contended the paper concludes by examining the role played by the adoption of child allowances after 1795 in the fertility increase of the early nineteenth century

seasonal hunger and its mitigation in north west bangladesh seasonal hunger may result from seasonality of agriculture when households fail to smooth income and consumption using household survey data from the northwest region of bangladesh this paper examines alternative measures of seasonal hunger and provides some evidence to support policies and programs needed to mitigate seasonal hunger the results suggest that a large majority of food vulnerable households are the perpetual poor as opposed to a small percentage of households who are subject to food deprivation only during the lean period findings suggest that government safety net programs and microcredit provide a cushion for the poor to stave off seasonal hunger