Biological Adaptation in Human Societies: a ‘Basic Needs’ Approach

The groundzero premise (so to speak) of the biological sciences is that survival and reproduction is the basic, continuing, inescapable problem for all living organisms; life is at bottom a survival enterprise. It follows that survival is the paradigmatic problem for human societies as well; it is a prerequisite for any other, more exalted objectives. Although the term adaptation is also familiar to social scientists, until recently it has been used only selectively, and often very imprecisely. Here a more rigorous and systematic approach to the concept of adaptation is proposed in terms of basic needs. The concept of basic human needs has a venerable history – tracing back at least to Plato and Aristotle. Yet the development of a formal theory of basic needs has lagged far behind. The reason is that the concept of objective, measurable needs is inconsistent with the theoretical assumptions that have dominated economic and social theory for most of this century, namely, valuerelativism and cultural determinism. Nevertheless, there have been a number of efforts over the past 30 years to develop more universalistic criteria for basic needs, both for use in monitoring social wellbeing (social indicators) and for public policy formulation. Here I will advance a strictly biological approach to perationalizing the concept of basic needs. It is argued that much of our economic and social life (and the motivations behind our revealed preferences and subjective utility assessments), not to mention the actions of modern governments, are either directly or indirectly related to the meeting of our basic survival needs. Furthermore, these needs can be specified to a first approximation and supported empirically to varying degrees, with the obvious caveat that there are major individual and contextual variations in their application. Equally important, complex human societies generate an array of instrumental needs which, as the term implies, serve as intermediaries between our primary needs and the specific economic, cultural and political contexts within which these needs must be satisfied. An explicit framework of Survival Indicators, including a profile of Personal Fitness and an aggregate index of Population Fitness, is briefly elucidated. Finally, it is suggested that a basic needs paradigm could provide an analytical tool (a biologic) for examining more closely the relationship between our social, economic and political behaviors and institutions and their survival consequences, as well as providing a predictive tool of some value.     

Natural conjugate priors for the instrumental variables regression model applied to the Angrist–Krueger data

We propose a natural conjugate prior for the instrumental variables regression model. The prior is a natural conjugate one since the marginal prior and posterior of the structural parameter have the same functional expressions which directly reveal the update from prior to posterior. The Jeffreys prior results from a specific setting of the prior parameters and results in a marginal posterior of the structural parameter that has an identical functional form as the sampling density of the limited information maximum likelihood estimator. We construct informative priors for the Angrist–Krueger [1991. Does compulsory school attendance affect schooling and earnings? Quarterly Journal of Economics 106, 979–1014] data and show that the marginal posterior of the return on education in the US coincides with the marginal posterior from the Southern region when we use the Jeffreys prior. This result occurs since the instruments are the strongest in the Southern region and the posterior using the Jeffreys prior, identical to maximum likelihood, focusses on the strongest available instruments. We construct informative priors for the other regions that make their posteriors of the return on education similar to that of the US and the Southern region. These priors show the amount of prior information needed to obtain comparable results for all regions.     

On the non-emptiness of the Mas-Colell bargaining set

We introduce an extension of the Mas-Colell bargaining set and construct, by an elaboration on a voting paradox, a superadditive four-person non-transferable utility game whose extended bargaining set is empty. It is shown that this extension constitutes an upper hemicontinuous correspondence. We conclude that the Mas-Colell bargaining set of a non-levelled superadditive NTU game may be empty.     

Fit performance of several programs used for non-linear least squares problems

Seven computerprograms for non-linear regression or curve fitting problems are compared. The comparison of the programs, running in different computing centra, is restricted to the fit performance. Six model functions are fitted according to the least squares criterion to data series, arising from practical work. The special least squares minimization programs turned out to be better suited for these problems than general optimizing programs.     

Economic progress and skill obsolescence with network effects

Summary. We construct an OLG model with network effects to examine skill obsolescence when individuals can choose technological vintages. In the absence of transfer payments, some regions of the parameter space have unique stationary equilibria, others have unique cyclical equilibria, and others have multiple stationary equilibria. All equilibria are Pareto efficient. However, rat race equilibria can exist in which all agents currently alive prefer a slower rate of progress than occurs in equilibrium. When contemporaneous transfers are allowed, equilibria are unique everywhere, but a cycle still exists, and a rat race can still arise in equilibrium. Allowing intertemporal transfers (debt) ensures that all equilibria are stationary. In the relevant parameter range, the introduction of debt can eliminate cycles and increase the long-run growth rate. No rat race equilibria exist when debt is allowed.Received: 3 January 2002, Revised: 3 June 2004, JEL Classification Numbers: 041, J24, O33. Correspondence to: Ian P. KingEarly versions of this paper were presented at the West Coast Macro Workshop, the Mid-West Macro Meetings, the Canadian Macroeconomics Study Group Meetings, and the Society for Economic Dynamics Meetings. We would like to thank V. V. Chari, Merwan Engineer, Don Ferguson, John Hillas, John Knowles, Dan Peled, Dan Usher, Linda Welling and Julian Wright for helpful comments. We are especially grateful to an anonymous referee for some very useful and substantive comments.     

Dynamic modelling of pollution abatement in a CGE framework

This paper deals with the specification of pollution abatement in dynamic computable general equilibrium (CGE) models and analyses the dynamic feedback mechanisms between economy and abatement in the context of environmental policy. A Ramsey-type economic model is presented, in which bottom-up technical and economic information on abatement techniques is integrated in a top-down dynamic CGE context. The practical suitability of the specification is illustrated by an empirical application for climate change and acidification in the Netherlands. The results show that a mixture of some slowdown of economic growth, a substantial restructuring of the economy and implementation of most technical abatement measures is optimal.     

Redistribution as a selection device

This paper studies the role of the wealth distribution for the market selection of entrepreneurs when agents differ in talent. It argues that the redistribution of initial endowments can increase an economy's surplus because more talented individuals get credit for their risky investment projects. Moreover, the redistribution of initial endowments may lead to a Pareto-improvement although all agents are non-satiable. An agent's entrepreneurial ability is his private information and there is moral hazard in production. I find conditions such that unproductive rich entrepreneurs crowd out productive poor ones on the capital market. Then redistribution of initial endowments may lead to a new equilibrium where market participants are better informed about the entrepreneurs’ ability. The new equilibrium is characterized by (i) the selection of better entrepreneurs, (ii) a higher riskless rate of return on capital, (iii) lower repayments of successful entrepreneurs to their creditors and (iv) the fact that all agents are better off.     

Unemployment Risk, Labour Force Participation and Savings

This paper analyses labour force participation and precautionary savings in the presence of risks of being fired or failing to secure a job offer when out of the labour market. We use a finite horizon framework with two employment states and a stage utility function which is CARA in consumption but non-separable in leisure. The results are that there is precautionary labour force participation: employment risk lowers the reservation wage; generally it also reduces consumption. However due to the non-separability assumption, precautionary savings, as usually defined, may not be positive. We characterize the reservation wage and contrast the results with those in which the stage utility is additive in leisure and consumption. We extend the analysis to study the effects of cyclical variation in employment risk, of stochastic future wage rates, and of adding a third employment state of search.     

The impact of corporate strategy on the capital structure of Australian companies

Research into the capital structure of firms has been the subject of extensive empirical investigation but further progress may be constrained by the conventional paradigm underlying most of this work. This paper seeks to extend the debate by examining the endogenous influence of corporate strategy on financing decisions made by firms. While the theoretical specification of the possible relationship has to be developed further, various models were constructed and company data from Australia, an economy with some notoriety for fairly loose corporate debt management, was used to examine various hypothesized relationships. Our analysis suggests that corporate strategy influences capital structure, particularly for the most diversified firms, and that the emerging relationship is complex. Profit, cash flow, the rate of growth and the level of earnings risk are important additional internal influences on capital structure. The results are reasonably robust and indicate that this focus of enquiry has considerable potential for further resolution of the capital structure puzzle, as well as contributing to the debate on the impact of institutional shareholders on the corporate strategy of the firms in which they invest.     

Model selection in random effects models for directed graphs using approximated Bayes factors

With the development of an MCMC algorithm, Bayesian model selection for the p ₂ model for directed graphs has become possible. This paper presents an empirical exploration in using approximate Bayes factors for model selection. For a social network of Dutch secondary school pupils from different ethnic backgrounds it is investigated whether pupils report that they receive more emotional support from within their own ethnic group. Approximated Bayes factors seem to work, but considerable margins of error have to be reckoned with.