Neuroeconomics: Why Economics Needs Brains

Neuroeconomics uses knowledge about brain mechanisms to inform economic theory. It opens up the “black box” of the brain, much as organizational economics opened up the theory of the firm. Neuroscientists use many tools—including brain imaging, behavior of patients with brain damage, animal behavior and recording single neuron activity. The key insight for economics is that the brain is composed of multiple systems which interact. Controlled systems (“executive function”) interrupt automatic ones. Brain evidence complicates standard assumptions about basic preference, to include homeostasis and other kinds of state‐dependence, and shows emotional activation in ambiguous choice and strategic interaction.     

DYNAMIC ASSET ALLOCATION AND CONSUMPTION CHOICE IN INCOMPLETE MARKETS*

We study the optimal investment and consumption problem of a CRRA investor when the drift and volatility of the stock are driven by a correlated factor. The myopic and non‐myopic components of the optimal portfolio process are characterised in terms of the market price of traded and non‐traded risk of the minimax martingale measure. We find that the optimal policies depend crucially on the nature of the agent, aggressive versus conservative, and the market incompleteness, improving versus deteriorating investment opportunities. Furthermore, we show that the original problem cannot be decomposed into a pure consumption and a pure terminal wealth problem, unless the market is complete.     

Output-inflation tradeoffs in 34 countries

This article examines the responsiveness of real output to the variability of inflation and aggregate demand. In the manner of Lucas (1973), estimates of the output-inflation tradeoff are computed for a large sample of countries. This measure is then correlated with the variances of the inflation rate and the growth rate in nominal income. Because differences in inflation variance (and hence the tradeoff) are viewed as the outcomes of differences in demand variance, correlations between these two variables are also reported. Cross-time and cross-country results provide a good measure of support for Lucas and the notion that attempts to exploit the tradeoff weaken it.     

The price adjustment and lead-lag relations between stock returns: microstructure evidence from the Taiwan stock market

This paper investigates the price adjustment and lead-lag relations between returns on five size-based portfolios in the Taiwan stock market. It finds evidence that the price adjustment of small-stock portfolios is not slower than that of large-stock portfolios. Additionally, limited evidence supports a positive leading role of large-stock portfolio returns over small-stock portfolio returns. These two findings are substantially different from the results of previous research on developed markets.     

Understanding the Economic Factors Influencing Farm Policy Preferences

A survey conducted in Mississippi, Texas, Indiana, and Nebraska elicited producers' preferences for various farm policy changes. This permitted examination of the diversity of preferences that single-state studies have not allowed. Five policy choices, including deficiency payments, loan programs, crop insurance, export programs, and disaster payments were examined. Logit model results predicting producer preferences for each of the five dichotomous policy choices are reported. Explanatory variables based on expected utility theory such as risk aversion, price and yield variability, and price–yield correlation are significant in various models.     

Are the Best Small Companies the Best Investments?

Previous research finds that large companies previously judged to be excellent growth companies have subsequently been poor investments. We examine small companies selected by Business Week on the basis of multiple criteria used in annual articles featuring highly rated growth companies. We study the investment performance over the three years before eleven annual Business Week publications and the three years after publication. We find positive excess returns in the pre‐publication period, but negative excess returns in the post‐publication period. This reversal in investment performance appears to be due to a mean‐reversion tendency in operating performance, in which the earnings and the past rates of return on capital of such companies subsequently decrease significantly.