GROUP FORAGING SENSITIVITY TO PREDICTABLE AND UNPREDICTABLE CHANGES IN FOOD DISTRIBUTION: PAST EXPERIENCE OR PRESENT CIRCUMSTANCES?

The ideal free distribution theory (Fretwell & Lucas, 1970) predicts that the ratio of foragers at two patches will equal the ratio of food resources obtained at the two patches. The theory assumes that foragers have "perfect knowledge" of patch profitability and that patch choice maximizes fitness. How foragers assess patch profitability has been debated extensively. One assessment strategy may be the use of past experience with a patch. Under stable environmental conditions, this strategy enhances fitness. However, in a highly unpredictable environment, past experience may provide inaccurate information about current conditions. Thus, in a nonstable environment, a strategy that allows rapid adjustment to present circumstances may be more beneficial. Evidence for this type of strategy has been found in individual choice. In the present experiments, a flock of pigeons foraged at two patches for food items and demonstrated results similar to those found in individual choice. Experiment 1 utilized predictable and unpredictable sequences of resource ratios presented across days or within a single session. Current foraging decisions depended on past experience, but that dependence diminished when the current foraging environment became more unpredictable. Experiment 2 repeated Experiment I with a different flock of pigeons under more controlled circumstances in an indoor coop and produced similar results.     

Effects of methylphenidate on sensitivity to reinforcement in children diagnosed with attention deficit hyperactivity disorder: an application of the matching law

The behavior of children diagnosed with attention deficit hyperactivity disorder (ADHD) has been hypothesized to be the result of decreased sensitivity to consequences compared to typical children. The present study examined sensitivity to reinforcement in 2 boys diagnosed with ADHD using the matching law to provide more precise and quantitative measurement of this construct. This experiment also evaluated the effects of methylphenidate (MPH) on sensitivity to reinforcement of children with ADHD. Subjects completed math problems to earn tokens under four different variable-interval (VI) schedules of reinforcement presented in random order under both medicated and nonmedicated conditions. Results showed that, in the medicated condition, the matching functions for both subjects resulted in higher asymptotic values, indicating an overall elevation of behavior rate under these conditions. The variance accounted for by the matching law was also higher under the medicated conditions, suggesting that their behavior more closely tracked the changing rates of reinforcement while taking MPH compared to placebo. Under medicated conditions, the reinforcing efficacy of response-contingent tokens decreased. Results are discussed with respect to quantifying behavioral changes and the extent to which the drug interacts with prevailing contingencies (i.e., schedule values) to influence behavioral variability.     

Informed consent and the use of placebo in poland: Ethical and legal aspects

The concept of informed consent was one of the most fruitful ideas that deeply changed the relationships between physicians and their patients from paternalism to respect for the personal autonomy of subjects needing professional medical care. The great progress in medicine, also involving the pharmaceutical industry, has created an increasing need to perform different clinical and experimental trials. The evolution of clinical research in the last decades has influenced strongly the design of these studies. One of the most important changes in this field has been the use of placebo groups in double-blind controlled studies. The controversies have involved not only the use of placebo when standard or proven treatment was available, but also some specific problems concerning the procedure of obtaining informed consent in such trials. This paper briefly presents the evolution of informed consent in Poland as well as different ethical and legal problems concerning informed consent and the use of placebo controls in clinical trials. An earlier version of this paper was presented at an international conference, “Placebo: Its Action and Place in Health Research Today,” held in Warsaw, Poland on 12–13 April, 2003.     

The Incoherence of the Patriotic State: A Critique of ‘Constitutional Patriotism’

Habermas proposes a new solution to the problematic relation between republican values and democracy. He asserts that a new model of social cohesion is needed and he suggests that the sense of community in a democratic society should be founded exclusively on the acceptance and support of a system of constitutionally established rules which are the logical result of the historical evolution of constitution-making. He argues that an account of the constitutional process which led to the formation of the modern republican state should provide the criteria for a rational set of norms which will exclude nationalism from the political arena. In this article, I point out the democratic hazards and the internal incoherence of Habermass alternative to the national state and I argue that a theoretical substitute should consider the existence of national identities as one of the aspects of modern pluralistic society.I should like to thank Zenon Bankowski, Bob Brecher, Emilios Christodoulidis, Alasdair Fay, Peter Fitzpatrick, Stefania Morandini, Rick Mohr and Res Publicas anonymous reviewers for their very helpful comments.     

Effects of alternative reinforcement on human behavior: the source does matter

Competing theories regarding the effects of delivering periodic response-independent reinforcement (more accurately, response-independent points exchanged for money) on a baseline rate of behavior were evaluated in human subjects. Contiguity theory holds that these events decrease target responding because incompatible behavior is adventitiously strengthened when the point deliveries follow target behavior closely in time. Matching theory holds that response-independent points, like any other alternative reinforcer, should reduce target responding. On this view, temporal contiguity between target responding and response-independent point delivery is unimportant. In our experiment, four different responses (moving a joystick in four different directions) were reinforced with points exchangeable for money according to four independent variable-interval schedules. Different schedules of point delivery were then superimposed on these baselines. When all superimposed point deliveries occurred immediately after one of the four responses (the target response), time allocated to target responding increased. When the superimposed point deliveries could be delivered at any time, time allocated to target responding declined and other behavior increased. When superimposed points could never immediately follow target responses, time allocated to target responding decreased further and other behavior or pausing predominated. The findings underscore the contribution of temporal contiguity in the effects of response-independent deliveries of food, money, points, etc.     

评中国思想家对道德与法律之关系的探索

儒家礼法合一论的真义是对“善法”的追求 ,对“恶法”的否定。因为善法体现了儒家的道德精神 ,反映了一种人道主义的价值取向 ,而恶法则是反人道的。墨家强调“法不仁不可以为法” ,其真实的意思是不道德的法律不是真正的法律 ,与儒家的礼法合一论有相似之处。法家主张“法虽不善犹善于无法” ,从而否定了法律的道德基础和价值根据。今天 ,我们在立法中贯彻道德的法律化取向需要谨慎从事 :一是注意把那些体现时代精神、合乎社会潮流的道德予以法律化 ,不能把落伍于时代的道德法律化 ;二是切忌把过高的道德义务转化为法律义务。必须认识到 ,应该法律化的道德只是“底线道德” ,而高层次的道德是不宜法律化的 ,否则就是强人所难。     

Thermodynamics: What One Needs to Know

Thermodynamics is the foundation of many of the topics of interest in the religion-science dialogue. Here a nonmathematical outline of the principles of thermodynamics is presented, providing a historical and conceptually understandable development that can serve teachers from disciplines other than physics. The contributions of Gibbs to both classical and rational thermodynamics, emphasizing the importance of the ensemble in statistical mechanics, are discussed. The seminal ideas of Boltzmann on statistical mechanics are contrasted to those of Gibbs in a discussion of the microscopic interpretation of the second law. The role of information theory is discussed, and the modern ideas of Prigogine and nonequilibrium are outlined in some detail with further reference to the second law. Implications for our interaction with God are considered.     

Drug discrimination under a concurrent fixed-ratio fixed-ratio schedule.

Pigeons were trained to discriminate 5.0 mg/kg pentobarbital from saline under a two-key concurrent fixed-ratio 10 fixed-ratio 40 schedule of food presentation, in which the fixed-ratio component with the lower response requirement was programmed to reinforce responding on one key after drug administration (pentobarbital-biased key) and on the other key after saline administration (saline-biased key). After responding stabilized, pigeons averaged 98% of their responses on the pentobarbital-biased key during training sessions preceded by pentobarbital, and they averaged 90% of their responses on the saline-biased key during training sessions preceded by saline. In test sessions preceded by doses of pentobarbital, chlordiazepoxide, or ethanol, pigeons switched from responding on the saline-biased key at low doses to responding on the pentobarbital-biased key at higher doses (the dose-response curve was quantal). High doses of phencyclidine produced responding on both keys, whereas pigeons responded almost exclusively on the saline-biased key after all doses of methamphetamine. These and previous experiments using concurrent reinforcement schedules to study drug discrimination illustrate that the schedule of reinforcement is an important determinant of the shape of dose-effect curves in drug-discrimination experiments.     

Christian Ethics,Religious Ethics,and Secular Ethics: A Contemporary Reappraisal

In this essay, I argue that Christian ethicists should not think of themselves as religious ethicists. I defend this claim by arguing that the concept of religious ethics, as it has come to be understood as a discipline that is distinct from secular ethics, is incoherent. In part one, I describe the fraught attempts by theologians in the 20th century to identify the distinctiveness of Christian ethics. In part two, I argue that certain accounts of natural law unwittingly reinforce a problematic conception of secular ethics. Part three examines some trends in religious studies and comparative religious ethics to highlight problematic conceptions of religion. Drawing together these strands of inquiry, I contend that that the secular-religious dichotomy in contemporary ethics should be rejected, but by the same token, I suggest that comparative ethics remains a worthwhile enterprise.