We study the performance of heuristics relative to the performance of optimal solutions in the rich domain of sequential search, where the decision to stop the search depends only on the applicant’s relative rank. Considering multiple variants of the secretary problem, that vary from one another in their formulation and method of solution, we find that descriptive heuristics perform well only when the optimal solution prescribes a single threshold value. We show that a computational heuristic originally proposed as an approximate (...) solution to a single variant of the secretary problem performs equally well in many other variants where the optimal solution prescribes multiple threshold values that gradually relax the criterion for stopping the search. Finally, we propose a new heuristic with near optimal performance in a competitive or strategic variant of the secretary problem with multiple employers competing with one another to hire job applicants. Both heuristics share a simple computational component: the ratio of the number of interviewed applicants to the number of those remaining to be searched. We present the subgame-perfect Nash equilibrium for this competitive variant and an algorithm for its computation. (shrink)

The Braess Paradox (BP) is a counterintuitive finding that degrading a network that is susceptible to congestion may decrease the equilibrium travel cost for each of its users. We illustrate this paradox with two networks: a basic network with four alternative routes from a single origin to a single destination, and an augmented network with six alternative routes. We construct the equilibrium solutions to these two networks, which jointly give rise to the paradox, and subject them to experimental testing. Our (...) purpose is to test the generality of the BP when the network is enriched as well as the effects of the information provided to the network users when they conclude their travel. To this end, we compare experimentally two information conditions when each of the two networks is iterated in time. Under public monitoring each user is accurately informed of the route choices and payoffs of all the users, whereas under private monitoring she is only informed of her own payoff. Under both information conditions, over iterations of the basic and augmented games, aggregate route choices converge to equilibrium. (shrink)

Within the last decade, there has been a dramatic bloom in ridesharing businesses along with the emergence of new enabling technologies. A central issue in ridesharing, which is also important in the general domain of cost-sharing in economics and computer science, is that the sharing of cost implies positive externalities and hence coordination problems for the network users. We investigate these problems experimentally in the present study. In particular, we focus on how sequential observability of transportation mode choices can be (...) a powerful facilitator of coordination in ridesharing. Our study abstracts the essential issues of coordination in ridesharing into a directed network game with experimentally testable predictions. In line with the theoretical analysis, our experimental evidence shows that even a limited extent of sequential choice observability might lead to efficient coordination. However, convergence to efficiency is slower with more limited observability, resulting in a significant increase in travel cost. (shrink)

We consider a class of dynamic tournaments in which two contestants are faced with a choice between two courses of action. The first is a riskless option (“hold”) of maintaining the resources the contestant already has accumulated in her turn and ceding the initiative to her rival. The second is the bolder option (“roll”) of taking the initiative of accumulating additional resources, and thereby moving ahead of her rival, while at the same time sustaining a risk of temporary setback. We (...) study this tournament in the context of a jeopardy race game (JRG), extend the JRG to $N > 2$ contestants, and construct its equilibrium solution. Compared to the equilibrium solution, the results of three experiments reveal a dysfunctional bias in favor of the riskless option. This bias is substantially mitigated when the contestants are required to commit in advance how long to pursue the risky course of action. (shrink)

Singularity Hypotheses: A Scientific and Philosophical Assessment offers authoritative, jargon-free essays and critical commentaries on accelerating technological progress and the notion of technological singularity. It focuses on conjectures about the intelligence explosion, transhumanism, and whole brain emulation. Recent years have seen a plethora of forecasts about the profound, disruptive impact that is likely to result from further progress in these areas. Many commentators however doubt the scientific rigor of these forecasts, rejecting them as speculative and unfounded. We therefore invited prominent (...) computer scientists, physicists, philosophers, biologists, economists and other thinkers to assess the singularity hypotheses. Their contributions go beyond speculation, providing deep insights into the main issues and a balanced picture of the debate. (shrink)

Recent studies based on next‐generation DNA sequencing have revealed that the female inactive X chromosome is replicated in a rapid, unorganized manner, and undergoes increased rates of mutation. These observations link the organization of DNA replication timing to gene regulation on one hand, and to the generation of mutations on the other hand. More generally, the exceptional biology of the inactive X chromosome highlights general principles of genome replication. Cells may control replication timing by a combination of intrinsic replication origin (...) properties, local chromatin states and global levels of replication factors, leading to a functional separation between the activity of genes and their mutation. (shrink)

It remains to summarize the contributions which each of the three disciplines discussed here is making toward the development of a science of man. "Significs" makes a study of the effects on human behavior of the linguistic aspects of the evaluative process, the most distinctly human aspect of the behavior of the human organism. "Mathematical Biophysics" seeks to describe the events associated with evaluative processes in physico-mathematical terms. "Cybernetics" is discovering important invariants common to these processes and others, particularly those (...) observed in man-made machines and in situations which lend themselves to description in thermo-dynamic or statistical terms. (shrink)

We examine the philosophical disputes among computer scientists concerning methodological, ontological, and epistemological questions: Is computer science a branch of mathematics, an engineering discipline, or a natural science? Should knowledge about the behaviour of programs proceed deductively or empirically? Are computer programs on a par with mathematical objects, with mere data, or with mental processes? We conclude that distinct positions taken in regard to these questions emanate from distinct sets of received beliefs or paradigms within the discipline: – The rationalist (...) paradigm, which was common among theoretical computer scientists, defines computer science as a branch of mathematics, treats programs on a par with mathematical objects, and seeks certain, a priori knowledge about their ‘correctness’ by means of deductive reasoning. – The technocratic paradigm, promulgated mainly by software engineers and has come to dominate much of the discipline, defines computer science as an engineering discipline, treats programs as mere data, and seeks probable, a posteriori knowledge about their reliability empirically using testing suites. – The scientific paradigm, prevalent in the branches of artificial intelligence, defines computer science as a natural (empirical) science, takes programs to be entities on a par with mental processes, and seeks a priori and a posteriori knowledge about them by combining formal deduction and scientific experimentation. We demonstrate evidence corroborating the tenets of the scientific paradigm, in particular the claim that program-processes are on a par with mental processes. We conclude with a discussion in the influence that the technocratic paradigm has been having over computer science. (shrink)

Informed consent began as a way of protecting physicians against legal liability. It did so by requiring physicians to provide their patients with sufficient information so that the patients could assent to or withhold consent from a proffered medical treatment. It was also intended to be an accurate expression of the patient's wishes. As such, it established the conditions by which a patient could be held responsible for his decisions concerning medical treatment.

Let us begin by proposing a sort of common denominator of the various conceptions of rationality, some feature that underlies practically all its definitions.

This is the story of the clattering of elevated subways and the cacophony of crowded neighborhoods, the heady optimism of industrial progress and the despair of economic recession, and the vibrancy of ethnic cultures and the resilience of ...

Research studies on Corporate Social Responsibility often focus on revealing corporate leaders’ attitudes toward various issues of CSR. The position of the present paper is that to understand CSR, we must grasp the collaborative perspective of CSR, and discern the attitudes of community leaders as well as corporate leaders. To this end, the study compares attitudes of community leaders with those of corporate leaders in three localities in Israel. The study examines various issues of CSR, highlighting the benefits to both (...) community and corporation of reciprocal relations. Results from t‐tests confirmed significant differences between the groups. Some important implications for CSR particularly in terms of collaboration between community and corporation are discussed. (shrink)

Property law plays a crucial role in the ability of groups, especially ones composed of geographically-adjacent members, to establish and maintain significant forms of "community" around a shared social, economic, or ideological interest. Property may also, however, have the opposite effect of undermining or even destroying communities, particularly those that rely on fragile modes of cooperation. This Article identifies three major types of territorial communities: Intentional Communities—close-knit groups that initially organize around a consolidating non-instrumental idea and employ sweeping internal norms (...) to validate their communality. Planned Communities — comprised mostly of residential developments of homeowners associations, which rely on a formal set of conditions, covenants, and restrictions incorporated in the association’s governing documents. Spontaneous Communities — clusters of initially unorganized neighbors who succeed in cooperating and coordinating over time. The evolvement of such organizations may be essential to the creation of an interpersonal "social capital" and to a physical and functional improvement of the community’s surroundings. For each one of these types of communities, property law plays a very different role. Thus, while Intentional Communities do not strictly hinge upon the existence of a supportive property system to flourish, Planned Communities cannot be conceived without the security of an overt, formal, state-backed regime, and Spontaneous Communities may often need property law’s affirmative backing to thrive and enjoy the social and economic benefits of sustainable collective action. (shrink)

The Construction of Property identifies the structural and institutional foundations of property, and explains how these features can accommodate various normative agendas. Offering rich and cutting-edge analysis, the book studies the spectrum of property regimes including private, common and public property as well as innovative forms of property hybrids such as US-style residential community associations, the British Private Finance Initiative, the Israeli Renewing Kibbutz, community land trusts and grassroots phenomena of property ordering in publicly-owned open spaces. It also investigates the (...) protagonists of property beyond the individual and the state, identifying the key role that community organisations and business corporations play for both the private and public aspects of property. The book then addresses property's greatest challenge: the move from a largely domestic legal construct into one that accommodates the increasing social and economic forces of globalisation. (shrink)