Amount and time exert independent influences on intertemporal choice

Intertemporal choices involve trade-offs between the value of rewards and the delay before those rewards are experienced. Canonical intertemporal choice models such as hyperbolic discounting assume that reward amount and time until delivery are integrated within each option prior to comparison1,2. An alternative view posits that intertemporal choice reflects attribute-wise processes in which amount and time attributes are compared separately3–6. Here, we use multi-attribute drift diffusion modelling (DDM) to show that attribute-wise comparison represents the choice process better than option-wise comparison for intertemporal choice in a young adult population. We find that, while accumulation rates for amount and time information are uncorrelated, the difference between those rates predicts individual differences in patience. Moreover, patient individuals incorporate amount earlier than time into the decision process. Using eye tracking, we link these modelling results to attention, showing that patience results from a rapid, attribute-wise process that prioritizes amount over time information. Thus, we find converging evidence that distinct evaluation processes for amount and time determine intertemporal financial choices. Because intertemporal decisions in the lab have been linked to failures of patience ranging from insufficient saving to addiction7–13, understanding individual differences in the choice process is important for developing more effective interventions

Stable and Efficient Electronic Business Networks: Key Players and the Dilemma of Peripheral Firms

This paper studies a spatial model of electronic business network formation where firms build links based on a cost-benefit analysis. Benefits result from directly and indirectly connected firms in terms of knowledge flows, which are heterogeneous: a key-player(e.g. a firm providing an exchange platform in a business-to-business network) provides a higher level of knowledge flows than peripheral firms (e.g. tier 3 suppliers in a vertically differentiated industry). For intermediate cost values of link formation, stable andefficient network structures comprise only a subset of the total set of firms, excluding peripheral firms which are most distantly located to the key player. When link formation implies a certain degree of network congestion, the stable and efficient network size issmaller than in a model with bilateral decisions upon link formation between two firms

The differential impact of friendship on cooperative and competitive coordination

Friendship is commonly assumed to reduce strategic uncertainty and enhance tacit coordination. However, this assumption has never been tested across two opposite poles of coordination involving either strategic complementarity or substitutability. We had participants interact with friends or strangers in two classic coordination games: the stag hunt game, which exhibits strategic complementarity and may foster "cooperation", and the entry game, which exhibits strategic substitutability and may foster "competition". Both games capture a frequent trade-off between a potentially high paying but uncertain option and a low paying but safe alternative. We find that, relative to strangers, friends are more likely to choose options involving uncertainty in stag hunt games but the opposite is true in entry games. Furthermore, in stag hunt games, friends "tremble" less between options, coordinate better and earn more, but these advantages are largely decreased or lost in entry games. We further investigate how these effects are modulated by risk attitudes, friendship qualities and interpersonal similarities

Revisiting the 'Cotton Problem': A Comparative Analysis of Cotton Reforms in Sub-Saharan Africa

The cotton sector has been amongst the most regulated in Africa, and still is to a large extent in West and Central Africa (WCA), despite repeated refirm recommendations by international donors. On the other hand, orthodox refirms in East and Southern Africa (ESA) have not always yielded the expected results. This paper uses a stylised contracting model to investigate the link between market structure and equity and efficiency in sub-Saharan cotton sectors; explain the outcomes of refirms in ESA; and analyze the potential consequences of orthodox refirms in WCA. We argue that the level of the world price and of government intervention, the nature of pre-refirm institutional organisation, as well as the degree of parastatal inefficiency, all contribute to making refirms less attractive to firmers and governments in WCA today, as compared to ESA in the 1990s.We illustrate our arguments with empirical observations on the perfirmance of cotton sectors across sub-Saharan Africa

What Factors Determine the Number of Trading Partners?

The purpose of the paper is to provide a simple model explaining buyer-supplier relationships and show what factors determine the number of trading partners. We show that when the supplier is able to determine the number of trading partners, the optimal number is small if the supplier's bargaining power with them is weak, the economy of scope in the supplier's variable costs is significant, and that in its sunk investment is weak. Investment may be greater when the number of trading partners is small. The results may be consistent with the formation of Japanese buyer-supplier relations

Creating an Efficient Culture of Cooperation

Throughout human history, informal sanctions by peers were ubiquitous and played a key role in the enforcement of social norms and the provision of public goods. However, a considerable body of evidence suggests that informal peer sanctions cause large collateral damage and efficiency costs. This raises the question whether peer sanctioning systems exist that avoid these costs and whether other, more centralized, punishment systems are superior and will be preferred by the people. Here, we show that efficient peer sanctioning without much need for costly punishment emerges quickly if we introduce two relevant features of social life into the experiment: (i) subjects can migrate across groups with different sanctioning institutions and (ii) they have the chance to achieve consensus about normatively appropriate behavior. We also show that subjects universally reject peer sanctioning without a norm consensus opportunity – an institution that has hitherto dominated research in this field – in favor of our efficient peer sanctioning institution or an equally efficient institution where they delegate the power to sanction to an elected judge. Migration opportunities and normative consensus building are key to the quick emergence of an efficient culture of universal cooperation because the more prosocial subjects populate the two efficient institutions first, elect prosocial judges (if institutionally possible), and immediately establish a social norm of high cooperation. This norm appears to guide subjects' cooperation and punishment choices, including the virtually complete removal of antisocial punishment when judges make the sanctioning decision