Schumpeterian process competition, welfare and laissez-faire: An experiment in artificial economic evolution

A simulation model is used to construct a regime of artificial economic evolution, where Schumpeterian process competition prevails, in the presence of technological uncertainty and bounded rationality. The output decision of the firm is represented by a behavioural algorithm, which allows for the presence of collusive behaviour. The purpose of the experiments is to go some way towards addressing the twin issues of the nature of the relationship between market structure and industry performance in a dynamic setting, and the contention that the evolutionary metaphor implies a laissez-faire stance with respect to policy issues. Under the simplifying assumptions of the model, experiments suggest that industries which generate high average concentration over a given period can compare favourably with industries that generate low average concentration, if the time profiles of both welfare and concentration are analysed. Also, the experiments suggest that the industry will naturally evolve a structure best suited to exploit the technological environment, but despite this there is still a role for intervention into the competitive process.     

Price and quantity competition under free entry

This paper complements that of Cellini et al. (Cellini, R., Lambertini, L., Ottaviano, G. I. P., 2004. Welfare in a differentiated oligopoly with free entry: A cautionary note. Research in Economics, 58:125–33.), which shows that Cournot competition may generate higher welfare compared to Bertrand competition in an economy with free entry. Unlike them, we provide a more general proof for this result and show that Cournot competition generates higher welfare compared to Bertrand competition when the products are sufficiently differentiated. If the products are close substitutes, welfare is higher under Bertrand competition. We show that these qualitative results hold whether or not number of varieties increases market size. We also show when the active firms earn higher profits under Bertrand competition compared to Cournot competition.     

Sampling equilibrium, with an application to strategic voting

We suggest an equilibrium concept for a strategic model with a large number of players in which each player observes the actions of only a small number of the other players. The concept fits well situations in which each player treats his sample as a prediction of the distribution of actions in the entire population, and responds optimally to this prediction. We apply the concept to a strategic voting model and investigate the conditions under which a centrist candidate can win the popular vote although his strength in the population is smaller than the strengths of the right and left candidates.     

Beauty contest,bounded rationality,and sentiment pricing dynamics

We present a dynamic asset pricing model that incorporates investor sentiment, bounded rationality and higher-order expectations to study how these factors affect asset pricing equilibrium. In the model, we utilize a two-period trading market and investors make decisions based on the heterogeneous expectations principle and the “sparsity-based bounded rational” sentiment. We find that bounded rationality results in mispricing and reduces it in next period. Investor sentiment produces more significant effects than private signals, optimistic investor sentiment increases hedging demand, thus causing prices to soar. Higher-order investors are more rational and attentive to the strategies of other participants rather than private signals. This model also derives the dampening effect of higher-order expectations to price volatility and the heterogeneity expectation depicts inconsistent investor behavior in financial markets. In the model, investors' expectations about future price is distorted by their sentiment and bounded rationality, so they obtain a biased mean from the signal extraction.     

An experimental study of persuasion bias and social influence in networks

In many areas of social life, individuals receive information about a particular issue of interest from multiple sources. When these sources are connected through a network, then proper aggregation of this information by an individual involves taking into account the structure of this network. The inability to aggregate properly may lead to various types of distortions. In our experiment, four agents all want to find out the value of a particular parameter unknown to all. Agents receive private signals about the parameter and can communicate their estimates of the parameter repeatedly through a network, the structure of which is known by all players. We present results from experiments with three different networks. We find that the information of agents who have more outgoing links in a network gets more weight in the information aggregation of the other agents than under optimal updating. Our results are consistent with the model of “persuasion bias” of DeMarzo et al. (2013. Q. J. Econ., 909) and at odds with an alternative heuristic according to which the most influential agents are those with more incoming links.     

Forward trading and collusion in oligopoly

We consider an infinitely repeated oligopoly in which at each period firms not only serve the spot market by either competing in prices or quantities but also have the opportunity to trade forward contracts. Contrary to the pro-competitive results of finite-horizon models, we find that the possibility of forward trading allows firms to sustain collusive profits that otherwise would not be possible to achieve. The result holds both for price and quantity competition and follows because (collusive) contracting of future sales is more effective in deterring deviations from the collusive plan than inducing the previously identified pro-competitive effects.     

Collective learning,innovation and growth in a boundedly rational,evolutionary world

We formulate a simple multiagent evolutionary scheme as a model of collective learning, i.e. a situation in which firms experiment, interact, and learn from each other. This scheme is then applied to a stylized endogenous growth economy in which firms have to determine how much to invest in R&D, where innovations are the stochastic product of their R&D activity, spillovers occur, but technological advantages are only relative and temporary and innovations actually diffuse, both at the intra and interfirm levels. The model demonstrates both the existence of a unique long-run growth attractor (in the linear case) and distinct growth phases on the road to that attractor. We also compare the long-run growth patterns for a linear and a logistic innovation function, and produce some evidence for a bifurcation in the latter case.     

Learning,forecasting and optimizing: An experimental study

Rational Expectations (RE) models have two crucial dimensions: (i) agents on average correctly forecast future prices given all available information, and (ii) given expectations, agents solve optimization problems and these solutions in turn determine actual price realizations. Experimental tests of such models typically focus on only one of these two dimensions. In this paper we consider both forecasting and optimization decisions in an experimental cobweb economy. We report results from four main experimental treatments: (1) subjects form forecasts only, (2) subjects determine quantity only (solve an optimization problem), (3) they do both and (4) they are paired in teams and one member is assigned the forecasting role while the other is assigned the optimization task. All treatments converge to Rational Expectation Equilibrium (REE), but at different speeds. We observe that performance is the best in treatment 1 and the worst in Treatment 3. We further find that most subjects use adaptive rules to forecast prices. Given a price forecast, subjects are less likely to make conditionally optimal production decisions in Treatment 3 where the forecast is made by themselves, than in Treatment 4 where the forecast is made by the other member of their team, which suggests that “two heads are better than one” in term of the speed of finding the REE.     

Cognitive ability and strategic sophistication

In three experiments we examine the extent to which strategic sophistication (i.e., inductive reasoning, iterative dominance and level-k thinking) is determined by broader cognitive skills. In the first experiment we replicate previous results showing strong associations between cognitive ability and sophistication in a game of iterative dominance and show that similar results arise in a game requiring induction. In the second two experiments we extend the literature in new directions. In Experiment 2 we modify the games to better capture participantsʼ ability to reason inductively and predict the sophistication of others and, again, find strong associations between cognitive ability, measured using a common IQ test, and sophistication. In Experiment 3 we examine more closely the causal nature of the relationship between cognitive ability and sophistication. We use a standard tool from cognitive psychology to randomly shock the cognitive ability of participants and show that this significantly affects game performance.     

The partially cursed and the analogy-based expectation equilibrium

Recent literature has established a link between the fully cursed equilibrium and the analogy-based expectation equilibrium. In this note, even the partially cursed equilibrium is shown to correspond to an analogy-based expectation equilibrium.     

Adaptation and complexity in repeated games

The paper presents a learning model for two-player infinitely repeated games. In an inference step players construct minimally complex inferences of strategies based on observed play, and in an adaptation step players choose minimally complex best responses to an inference. When players randomly select an inference from a probability distribution with full support the set of steady states is a subset of the set of Nash equilibria in which only stage game Nash equilibria are played. When players make ‘cautious’ inferences the set of steady states is the subset of self-confirming equilibria with Nash outcome paths. When players use different inference rules, the set of steady states can lie between the previous two cases.     

Nationalism, development and integration: the political economy of Ernest Gellner

In this paper, we show how in Gellner we can find a stimulatinganalysis of the institutional equilibria that characterise agrarianand industrial society and the conditions that make possibleinstitutional change from one equilibrium to another. This allowsa convincing account of the reasons why some countries industrialisedbefore others and why nationalism had such an uneven impacton the development of market economies. We consider the relationbetween Gellner's analysis and other theories of organisationand point out how Gellner can help to solve some paradoxes thatarise in these theories. We also argue that joining Gellner'scontribution to the analysis of the positional nature of statusand power reinforces his conclusion about the necessary stagnationof agrarian societies and the necessary (over)accumulation ofdifferent forms of capitalism. We conclude by examining theimplications of his analysis for the process of globalisationand its challenge to national states.     

Market power of firms and exchange-rate fluctuations

This paper explores the potential of firms to restrict industry outputs (market power) in oligopolistically organized markets where domestic firms compete with foreign ones. Within a stochastic price-setting supergame framework, market power is shown to be lower in general with flexible exchange rates for the following reasons. (i) The conditions that the fully collusive outcome—oligopolists maximizing joint profits — is sustainable in equilibrium become stronger if the exchange rate fluctuates, provided that fluctuations are sufficiently small. (ii) Even if full collusion can be sustained, industry outputs will be higher on the average with flexible than with fixed exchange rates.     

企业最优定价策略与汇率传递效应研究

文章在李嘉图理论模型的框架下讨论了两国企业的最优定价策略,在此基础上分析了汇率传递效应。研究表明,汇率传递效应具有某种突变性,其突变的边界条件依赖于两国市场需求特征、贸易摩擦与两国企业的边际成本。     

Learning by trial and error

A person learns by trial and error if he occasionally tries out new strategies, rejecting choices that are erroneous in the sense that they do not lead to higher payoffs. In a game, however, strategies can become erroneous due to a change of behavior by someone else. We introduce a learning rule in which behavior is conditional on whether a player experiences an error of the first or second type. This rule, called interactive trial and error learning, implements Nash equilibrium behavior in any game with generic payoffs and at least one pure Nash equilibrium.     

Monopolists and viscous demand

We characterize the optimal dynamic price policy of a monopolist who faces “viscous” demand for its services. Demand is viscous if it adjusts relatively slowly to price changes. We show that with the optimal policy the monopolist stops short of achieving 100% market penetration, even when all of the consumers have the same long-run willingness to pay for the service. Furthermore, for certain parameter values in the model, the price policy requires rapid oscillations of the price path.     

考虑港口收费管制的进出口贸易竞争研究

考虑港口的收费管制因素,建立了进出口贸易竞争模型。该模型由一个出口国和两个进口国组成,且各国都拥有一个港口,位于出口国的两家公司均向两个进口国销售商品,并在各个进口国展开市场竞争（古诺竞争或伯川德竞争）,各贸易国的港口根据其是否存在价格管制确定港口收费。针对进出口公司的每种竞争模式,得到了不同的港口收费管制组合下各贸易国的港口收费、港口利润和社会福利,并将竞争均衡结果进行了比较。研究发现： （1）在进出口公司古诺竞争模式下,若三个贸易国的港口都无收费管制（有收费管制）且进出口产品的差异较大 （小）时,各贸易国的社会福利和港口利润均更高; （2）在进出口公司伯川德竞争模式下,若进出口产品的差异较大 （小）,则出口国的港口利润主要取决于港口收费 （贸易量）,而进口国恰好相反; （3）当进出口产品的差异较大 （小）时,进出口公司在古诺 （伯川德）竞争模式下各贸易国的社会福利、港口利润以及港口使用费都更高。     

Non-computable strategies and discounted repeated games

Summary A number of authors have used formal models of computation to capture the idea of bounded rationality in repeated games. Most of this literature has used computability by a finite automaton as the standard. A conceptual difficulty with this standard is that the decision problem is not closed. That is, for every strategy implementable by an automaton, there is some best response implementable by an automaton, but there may not exist any algorithm forfinding such a best response that can be implemented by an automaton. However, such algorithms can always be implemented by a Turing machine, the most powerful formal model of computation. In this paper, we investigate whether the decision problem can be closed by adopting Turing machines as the standard of computability. The answer we offer is negative. Indeed, for a large class of discounted repeated games (including the repeated Prisoner's Dilemma) there exist strategies implementable by a Turing machine for whichno best response is implementable by a Turing machine.The work was begun while Nachbar was a visitor at The Center for Mathematical studies in Economics and Management Science at Northwestern University; he is grateful for their hospitality. We are also grateful to Robert Anderson and Neil Gretsky and to seminar audiences at UCLA for useful comments, and to the National Science Foundation and the UCLA Academic Senate Committee on Research for financial support. This paper is an outgrowth of work reported in Learning and Computability in Discounted Supergames.     

Three very simple games and what it takes to solve them

We study experimentally the nature of dominance violations in three minimalist dominance-solvable guessing games. Only about a third of our subjects report reasoning consistent with dominance; they all make dominant choices and almost all expect others to do so. Nearly two-third of our subjects report reasoning inconsistent with dominance, yet a quarter of them actually make dominant choices and half of those expect others to do so. Reasoning errors are more likely for subjects with lower working memory, intrinsic motivation and premeditation attitude. Dominance-incompatible reasoning arises mainly from subjects misrepresenting the strategic nature (payoff structure) of the guessing games.     

Cognitive Rules, Institutions, and Competition

Rules exert an important influence on rational individual behaviour. In economic analyses, two different types of rules occur that both induce rule-following behaviour. However, they are rarely distinguished. The differentiation of institutions (as interpersonal rules) and cognitive rules (as intrapersonal rules) allows for a clarification of substantial differences between the two types of rules, for example, concerning the incorporated knowledge and rule-persistence. Furthermore, the analysis of the interrelation of the two types of rules offers fruitful insights that still are not much explored in economics. The important dimensions to be considered are rule-harmony that stabilises institutional arrangements, and rule-conflict that induces pressure on persistent institutions. In this context, competition can be seen as a medium of interaction that allows individual agents to learn both about the behaviour of interacting agents and the nature and effects of the institutional framework. The integration of competition - as the core concept of economics - into the interplay of institutions and cognitive rules explores a missing point within the analysis of the economics of rules.