Hick's Law in a Stochastic Race Model with Speed-Accuracy Tradeoff

We present an analytic solution for a race model of n stochastic accumulators for multiple choice reaction time. We show that to maintain a constant level of accuracy, the response criterion needs to be increased approximately logarithmically with n, to compensate for the increase with n in the likelihood that an incorrect alternative will be most active after any fixed amount of time accumulating information. Assuming that participants monitor and maintain a constant level of performance can then explain the logarithmic dependency of the response latency on n as specified by Hick's law. Moreover, we show that for short time intervals, the Shannon information that observers extract from a stimulus, is predicted to increase linearly with processing time.     

Forgetting curves: implications for connectionist models

Forgetting in long-term memory, as measured in a recall or a recognition test, is faster for items encoded more recently than for items encoded earlier. Data on forgetting curves fit a power function well. In contrast, many connectionist models predict either exponential decay or completely flat forgetting curves. This paper suggests a connectionist model to account for power-function forgetting curves by using bounded weights and by generating the learning rates from a monotonically decreasing function. The bounded weights introduce exponential forgetting in each weight and a power-function forgetting results when weights with different learning rates are averaged. It is argued that these assumptions are biologically reasonable. Therefore power-function forgetting curves are a property that may be expected from biological networks. The model has an analytic solution, which is a good approximation of a power function displaced one lag in time. This function fits better than any of the 105 suggested two-parameter forgetting-curve functions when tested on the most precise recognition memory data set collected by. Unlike the power-function normally used, the suggested function is defined at lag zero. Several functions for generating learning rates with a finite integral yield power-function forgetting curves; however, the type of function influences the rate of forgetting. It is shown that power-function forgetting curves cannot be accounted for by variability in performance between subjects because it requires a distribution of performance that is not found in empirical data. An extension of the model accounts for intersecting forgetting curves found in massed and spaced repetitions. The model can also be extended to account for a faster forgetting rate in item recognition (IR) compared to associative recognition in short but not long retention intervals.     

Human group choice: discrete-trial and free-operant tests of the ideal free distribution

Ideal free distribution theory predicts that foragers will form groups proportional in number to the resources available in alternative resource sites or patches, a phenomenon termed habitat matching. Three experiments tested this prediction with college students in discrete-trial simulations and a free-operant simulation. Sensitivity to differences in programmed reinforcement rates was quantified by using the sensitivity parameter of the generalized matching law (s). The first experiment, replicating prior published experiments, produced a greater degree of undermatching for the initial choice (s = 0.59) compared to final choices (s = 0.86). The second experiment, which extended prior findings by allowing only one choice per trial, produced comparable undermatching (s = 0.82). The third experiment used free-operant procedures more typical of laboratory studies of habitat matching with other species and produced the most undermatching (s = 0.71). The results of these experiments replicated previous results with human groups, supported predictions of the ideal free distribution, and suggested that undermatching represents a systematic deviation from the ideal free distribution. These results are consistent with a melioration account of individual behavior as the basis for group choice.     

台湾实践基因科技应用于临床试验的政策发展可能视野

台湾目前的基因科技发展存在着瓶颈和危机。在日前台湾举办的《基因治疗与临床试验－务实取向的共识凝聚研讨会》上,与会者提出了制约台湾目前基因研究的十大瓶颈,以及面对困境的十项解决方案。     

Opinion on directive 98/44/EC on the legal protection of biotechnical inventions,and its implementation in Sweden

The following statement is the formal opinion by the Swedish National Council on Medical Ethics concerning the implementation of Directive 98/44/EC of the European Parliament concerning legal protection of biotechnical inventions, and the implications and implementation of this Directive in Sweden.     

Group choice: the ideal free distribution of human social behavior

Group choice refers to the distribution of group members between two choice alternatives over time. The ideal free distribution (IFD), an optimal foraging model from behavioral ecology, predicts that the ratio of foragers at two resource sites should equal the ratio of obtained resources, a prediction that is formally analogous to the matching law of individual choice, except that group choice is a social phenomenon. Two experiments investigated the usefulness of IFD analyses of human group choice and individual-based explanations that might account for the group-level events. Instead of nonhuman animals foraging at two sites for resources, a group of humans chose blue and red cards to receive points that could earn cash prizes. The groups chose blue and red cards in ratios in positive relation to the ratios of points associated with the cards. When group choice ratios and point ratios were plotted on logarithmic coordinates and fitted with regression lines, the slopes (i.e., sensitivity measures) approached 1.0 but tended to fall short of it (i.e., undermatching), with little bias and little unaccounted for variance. These experiments demonstrate that an IFD analysis of group choice is possible and useful, and suggest that group choice may be explained by the individual members' tendency to optimize reinforcement.     

The general matching law describes choice on concurrent variable-interval schedules of wheel-running reinforcement.

Six male Wistar rats were exposed to concurrent variable-interval schedules of wheel-running reinforcement. The reinforcer associated with each alternative was the opportunity to run for 15 s, and the duration of the changeover delay was 1 s. Results suggested that time allocation was more sensitive to relative reinforcement rate than was response allocation. For time allocation, the mean slopes and intercepts were 0.82 and 0.008, respectively. In contrast, for response allocation, mean slopes and intercepts were 0.60 and 0.03, respectively. Correction for low response rates and high rates of changing over, however, increased slopes for response allocation to about equal those for time allocation. The results of the present study suggest that the two-operant form of the matching law can be extended to wheel-running reinforcement. 'I'he effects of a low overall response rate, a short Changeover delay, and long postreinforcement pausing on the assessment of matching in the present study are discussed.     

性别选择与法律之回应——法理视野中的变性手术

变性人的出现对社会秩序及法律制度提出了挑战。自然人生而具有的人作为社会主体定在的自由和健康权利,为变性人享有性别选择的权利提供了法理支撑。在权利确认后,很有必要在变性手术的对象、施行者及程序上作出规范的应对,而变性人术后的社会角色及权利保护也应该得到法律的适时回应,以实现法的秩序、公正等价值。     

Emergency Research without Consent under Polish Law

Although Directive 2001/20/EC of the European Parliament and of Council of 4 April 2001 on the approximation of the laws regulations and administrative provisions of the Member States relating to the implementation of good clinical practice in the conduct of clinical trials on medicinal products for human use does not contain an exception for emergency situations, and requires the informed consent of a legal representative in all cases where research is conducted on legally competent individuals who are unable to give informed consent, in Poland, emergency research can be conducted without consent. Polish regulations on emergency research can hardly be treated as a result of intentional legislative policy. Our provisions arise from multiple and sophisticated interpretations of different regulations that govern medical experiments on human subjects and clinical trials. These interpretations can be summarized as follows: (1) There are two categories of medical experiments: therapeutic and non-therapeutic experiments. Emergency research without consent may be conducted in the category of therapeutic experiment only (therapeutic experiment consists of the introduction by the physician of new or only partially proven diagnostic, therapeutic or preventive methods in order to achieve direct benefit to the health of the patients, and it can be carried out when hitherto applied methods were ineffective or their effectiveness was insufficient). (2). Emergency research may be conducted without consent if there is a situation of great urgency in which the research subject's life is in danger and there is no possibility of obtaining immediate consent from the research subject him or herself, or from his or her legal representative or guardianship court, and the research subject has not refused to give consent for the participation in an emergency therapeutic experiment. The legal representative or guardianship court shall be provided with all the relevant information concerning subject's participation in an experiment as soon as possible. All projects of emergency research with intent to be done without the research subject's consent must be approved by an independent bioethics committee. Because these five requirements seem to provide insufficient protection for a subject's autonomy and rights it is necessary to add to them two other conditions: (1) the emergency research could not be conducted using other research participants capable of giving informed consent; and (2) informed consent for continued participation in the emergency research shall be obtained from either the participant him or herself or the legally authorized representative as soon as possible (requirement of obtaining deferred consent). A consolidated single Act that will govern all aspects of medical experiments on human subjects, including emergency research, should be prepared and enacted as soon as possible.     

The Admissibility of Research in Emergency Medicine

The main goal in this paper is to present the legal rules connected with medical experiment on human beings in emergency medicine and to explain the scope, significance, and meaning of these rules, especially with regard to their interpretation. As the provisions about medical experiments truly make sense only if they can be observed by the whole "civilised" international community, they are presented in the context of international law with reference to Polish law. By considering the appropriate regulations of research contained in legal documents, it is possible to formulate a catalogue of doctors' duties and patients' rights. This general catalogue refers to all kinds of medical research involving human beings. In the field of emergency medicine, general provisions are sometimes involved, and they are sometimes limited. The main and most important conclusion is that a medical experiment in emergency medicine is admissible only if previously indicated conditions based on general rules of conducting research are fulfilled.