According to the local risk-neutrality theorem an agent who has the opportunity to invest in an uncertain asset does not buy it or sell it short iff its expected value is equal to its price, independently of the agent's attitude towards risk. Contrary to that it is shown that, in the context of expected utility theory with differentiable vNM utility function, but without the assumption of stochastic constant returns to scale, nondegenerate intervals of no-trade prices may exist. With a quasiconcave (...) expected utility function they do if, and only if, the agent is risk averse of order one. (shrink)

Together, these collected papers develop the idea that human thinking - from scientific creativity to simply understanding what a positive HIV test means - "happens" partly outside the mind.".

Simple Heuristics That Make Us Smart invites readers to embark on a new journey into a land of rationality that differs from the familiar territory of cognitive science and economics. Traditional views of rationality tend to see decision makers as possessing superhuman powers of reason, limitless knowledge, and all of eternity in which to ponder choices. To understand decisions in the real world, we need a different, more psychologically plausible notion of rationality, and this book provides it. It is about (...) fast and frugal heuristics--simple rules for making decisions when time is pressing and deep thought an unaffordable luxury. These heuristics can enable both living organisms and artificial systems to make smart choices, classifications, and predictions by employing bounded rationality. But when and how can such fast and frugal heuristics work? Can judgments based simply on one good reason be as accurate as those based on many reasons? Could less knowledge even lead to systematically better predictions than more knowledge? Simple Heuristics explores these questions, developing computational models of heuristics and testing them through experiments and analyses. It shows how fast and frugal heuristics can produce adaptive decisions in situations as varied as choosing a mate, dividing resources among offspring, predicting high school drop out rates, and playing the stock market. As an interdisciplinary work that is both useful and engaging, this book will appeal to a wide audience. It is ideal for researchers in cognitive psychology, evolutionary psychology, and cognitive science, as well as in economics and artificial intelligence. It will also inspire anyone interested in simply making good decisions. (shrink)

The essays in this collection have been written for Gerd Buchdahl, by colleagues, students and friends, and are self-standing pieces of original research which have as their main concern the metaphysics and philosophy of science of the seventeenth and eighteenth centuries. They focus on issues about the development of philosophical and scientific thought which are raised by or in the work of such as Bernoulli, Descartes, Galileo, Kant, Leibniz, Maclaurin, Priestly, Schelling, Vico. Apart from the initial bio-bibliographical piece and (...) those by Robert Butts and Michael Power, they do not discuss Buchdahl or his ideas in any systematic, lengthy, or detailed way. But they are collected under a title which alludes to the book, Metaphysics and the Philosophy of Science: The Classical Origins, Descartes to Kant (1969), which is central in the corpus of his work, and deal with the period and some of the topics with which that book deals. (shrink)

Harald Weinrich's epilogue considers forgetting in the present age of information overflow, particularly in the area of the natural sciences."--Jacket.

“This is surely the ultimate expression of the top-down approach to consciousness, written with Sommerhoff's characteristic clarity and precision. It says far more than other books four times the size of this admirably concise volume. This book is destined to become a pillar of the subject.” —Rodney Cotterill, Technical University of Denmark The problem of consciousness has been described as a mystery about which we are still in a terrible muddle and in Understanding Consciousness: Its Function and Brain Processes, the (...) author attempts to unravel this mystery by offering a clarification of the main concepts related to consciousness, and positing a comprehensive biological explanation. Consequently, this book will be ideal for a wide-range of upper level undergraduate and postgraduate courses. The author interprets consciousness as a property that can be possessed by many creatures lacking a language faculty and comprises all of the following: awareness of the surrounding world; awareness of the self as an entity; and awareness of such things as thoughts and feelings. He argues that a biological approach can achieve both the necessary conceptual clarifications and a joint explanation of these divisions of awareness in terms of just two accurately defined concepts of 'internal representation' and two empirically supported assumptions about the functional architecture of a specific set of brain processes. Despite this striking simplicity, his model covers these divisions of awareness both as objective faculties of the brain and as subjective experience. These conclusions are applied to a broad range of fundamental questions, including the biological rationale of subjective experience and where consciousness resides in the neural networks. (shrink)

Heuristics are efficient cognitive processes that ignore information. In contrast to the widely held view that less processing reduces accuracy, the study of heuristics shows that less information, computation, and time can in fact improve accuracy. We review the major progress made so far: the discovery of less-is-more effects; the study of the ecological rationality of heuristics, which examines in which environments a given strategy succeeds or fails, and why; an advancement from vague labels to computational models of heuristics; the (...) development of a systematic theory of heuristics that identifies their building blocks and the evolved capacities they exploit, and views the cognitive system as relying on an “adaptive toolbox;” and the development of an empirical methodology that accounts for individual differences, conducts competitive tests, and has provided evidence for people’s adaptive use of heuristics. Homo heuristicus has a biased mind and ignores part of the available information, yet a biased mind can handle uncertainty more efficiently and robustly than an unbiased mind relying on more resource-intensive and general-purpose processing strategies. (shrink)

Within the highly organized nuclear structure, specific nuclear domains (ND10) are defined by accumulations of proteins that can be interferon-upregulated, implicating ND10 as sites of a nuclear defense mechanism.Compatible with such a mechanism is the deposition of herpesvirus, adenovirus, and papovavirus genomes at the periphery of ND10. However, these DNA viruses begin their transcription at ND10 and consequently initiate replication at these sites, suggesting that viruses have evolved ways to circumvent this potential cellular defense and exploit it. Other ND10-associated proteins (...) belong to ubiquitin-related pathways. These findings, together with the accumulation of various overexpressed cellular and viral proteins, suggest that ND10 function as nuclear dumps or as nuclear depots. Consistent with the recruitment or deposition of various proteins and viral genomes adjacent to ND10, ND10 themselves may only be protein accumulations at specific but as yet undefined nuclear deposition sites. The concept of specific nuclear deposition sites may explain the juxtaposition of various nuclear bodies and allows testable predictions about a potential supramolecular regulatory mechanism whereby proteins are selectively segregated or released by global changes induced in nuclear functions such as viral infections, stress, or hormonal induction. BioEssays 20:660–667, 1998.© 1998 John Wiley & Sons Inc. (shrink)

Unlike behaviorism, cognitive psychology relies on mental concepts to explain behavior. Yet mental processes are not directly observable and multiple explanations are possible, which poses a challenge for finding a useful framework. In this article, I distinguish three new frameworks for explanations that emerged after the cognitive revolution. The first is called tools‐to‐theories: Psychologists' new tools for data analysis, such as computers and statistics, are turned into theories of mind. The second proposes as‐if theories: Expected utility theory and Bayesian statistics (...) are turned into theories of mind, describing an optimal solution of a problem but not its psychological process. The third studies the adaptive toolbox (formal models of heuristics) that describes mental processes in situations of uncertainty where an optimal solution is unknown. Depending on which framework researchers choose, they will model behavior in either situations of risk or of uncertainty, and construct models of cognitive processes or not. The frameworks also determine what questions are asked and what kind of data are generated. What all three frameworks have in common, however, is a clear preference for formal models rather than explanations by general dichotomies or mere verbal concepts. The frameworks have considerable potential to inform each other and to generate points of integration. (shrink)

This volume collects Gigerenzer's recent articles on the psychology of rationality. This volume should appeal, like the earlier volumes, to a broad mixture of cognitive psychologists, philosophers, economists, and others who study decision making.