The biological roots of altruistic behavior

Richard P. Ebstein, Salomon Israel, Ariel Knafo and Gary Boornstein

Psychology Department, The Hebrew University of Jerusalem

The paradoxical nature of human altruism has long confounded a broad range of scientific disciplines ranging from economics to evolutionary biology. Neo-classical economic theory has long held by the axiom of maximizing individual utility with little regard to the ultimate welfare of others. Similarly, altruism, by increasing another's evolutionary fitness at the expense of one's own, is seemingly contradictory to the notion of Darwinian selection for 'selfish genes'. The advent of models such as kin selection, reciprocal altruism and multilevel selection, have posited the necessary conditions that lay the groundwork for altruism as an evolutionarily successful strategy. Likewise, a plethora of experimental economic studies have demonstrated the pervasiveness of 'other regarding' behavior, even under conditions of anonymity and no personal reward. Our laboratory merges these two disciplines by investigating the neurobiological and genetic basis for altruistic behavior. We have embarked on a research program exploring the molecular genetic influence of two well characterized nonapeptides, oxytocin and vasopressin, and their established role as 'social hormones' in lower mammals. Our ongoing studies have demonstrated an association between genetic polymorphisms in the receptors for these hormones and altruistic behavior in economic decision tasks involving people and real money payoffs. These findings demonstrate that the arginine vasopressin receptor 1a and the oxytocin receptor contribute to individual differences in cooperative behavior; with studies in progress examining the effect of intranasal administration of these two nonapeptides on a gamut of interrelated social phenotypes, including Theory of Mind, social stress, and economic decision making

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Materials and Language: Pre-Semitic Structural Change followed Transition to Agriculture

Noam Agmon

Institute of Chemistry, The Hebrew University of Jerusalem

Abstract: Materials and language have evolved together. Thus archaeological dating of materials possibly also dates the words which name them. Analysis of Proto-Semitic (PS) material terms reveals that Stone-Age materials have mostly biconsonantal (2c) names whereas metals and pottery are uniquely triconsonantal (3c). This establishes a major transition in pre-Semitic language structure, concomitant with the transition to agriculture. Moreover, materials utilized before 16,000 years ago (flint, stone, lime and cloth) have monosyllabic 2c names. Associations between 2c words in the lexicon reveal the original context of material utilization and the state of mind of the people who have coined the corresponding terms. The consistency of the model and its agreement with archaeological data suggests that the monosyllabic 2c core of PS is a remnant from the oldest prehistoric language yet identified, possibly originating within Paleolithic hunter-gatherer societies.

*Email: agmon@fh.huji.ac.il This work includes an etymological study by Yigal Bloch, Department of Jewish History, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.

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A Neuroeconomics Approach to the Matching Law

Yonatan Loewenstein

The Hebrew University of Jerusalem

According to Herrnstein's matching law, the frequency of choosing an alternative in a repeated-choice experiment is equal to the fraction of rewards obtained from that alternative. I will discuss three questions concerning the matching law, which range from synaptic physiology to economic theory. (1) What is the neural basis of the matching law? I will show that matching behavior naturally emerges if changes in synaptic efficacies in the brain are proportional to the covariance of reward and neural activity. (2) Is there a normative theory of matching? The standard normative theory of choice is utility maximization. But in some experiments, matching appears to be a better approximation to behavior than maximizing. I will show that a normative theory of matching can be constructed by regarding the animal or human subject not as a single self, but as a temporal succession of multiple selves. Then, matching is a Nash equilibrium of an intrapersonal game in which each of the multiple selves tries to maximize its immediate reward. (3) What are the implications of matching for microeconomic theory? Neoclassical conomics is based on the normative theory of utility maximization, which in many instances predicts deviations from the experimentally observed matching behavior. I will show that both matching and maximizing are special cases of a general theory of choice. This theory can be used to reformulate microeconomic theory with a potentially improved description of consumer behavior.

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Complexity in "Algorithmic Game Theory"

Noam Nisan

The Hebrew University of Jerusalem

In recent years, we have seen tremendous growth in an area of research that combines Computer-Science on one hand with Game-Theory and Economics on the other, with the Internet being a key application domain for this combination. This field is usually termed "algorithmic game theory", a name that, in my view, misses what is perhaps the most interesting difference between it and classical game theory and economic theory: the central place given to complexity.

In this talk I will sketch the types of issues studied in this new field, and highlight the role of complexity in it.