Unitization during Category Learning

Five experiments explored the question of whether new perceptual units can be developed if they are diagnostic for a category learning task, and if so, what are the constraints on this unitization process? During category learning, participants were required to attend either a single component or a conjunction of five components in order to correctly categorize an object. In Experiments 1-4, some evidence for unitization was found in that the conjunctive task becomes much easier with practice, and this improvement was not found for the single component task, or for conjunctive tasks where the components cannot be unitized. Influences of component order (Experiment 1), component contiguity (Experiment 2), component proximity (Experiment 3), and number of components (Experiment 4) on practice effects were found. Using a Fourier Transformation method for deconvolving response times (Experiment 5), prolonged practice effects yielded responses that were faster than expected by analytic model that integrate evidence from independently perceived components

The economic evolution of petroleum property rights in the United States.

We examine Harold Demsetz's (1967) prediction that property rights emerge and are refined as the benefits of doing so exceed the costs in the context of oil and gas resources in the U.S. Familiar influences on the development of petroleum property rights, technology, market demand, and politics, provide support for the hypothesis, and those issues are examined. Our primary contribution is to demonstrate the important role of a less familiar factor, the presence in the reservoir of both oil and gas with differentially volatile prices. This factor has affected the nature of the property rights assigned with unitization, an institutional arrangement to internalize the common pool externality. Information asymmetries and conflicting price expectations have resulted in unit agreements that would not have been predicted in a strict neo-classical sense. Our analysis provides new insights regarding the nature of voluntary unitization contracts, inherent limits to producers' ability to internalize externalities, and the welfare implications of compulsory unitization.