Human Signal-detection Performance: Effects Of Signal Presentation Probabilities And Reinforcer Distributions

University students participated in one of four standard two-choice signal-detection experiments in which signal presentation probability was varied and the reinforcement distribution was held constant and equal. In Experiments 1, 3 and 4, subjects' performance showed a systematic response bias for reporting the stimulus presented least often. Experiments 1 and 4 showed that this effect was reliable with extended training and monetary, rather than point, reinforcement. In Experiment 2, all correct responses were signaled in some way, and this produced the opposite relationship between signal presentation probability and response bias. Experiments 1 and 3 found that explicitly deducting money (intended as punishment) for equal numbers of incorrect responses on each alternative, or varying the obtained overall rate of reinforcement, produced no clear change in response bias. The bias, shown by humans, for reporting the stimulus presented least often remains a challenge for theories of stimulus detection.     

Physician-assisted suicide: the role of mental health professionals

A review of the literature was conducted to better understand the (potential) role of mental health professionals in physician-assisted suicide. Numerous studies indicate that depression is one of the most commonly encountered psychiatric illnesses in primary care settings. Yet, depression consistently goes undetected and undiagnosed by nonpsychiatrically trained primary care physicians. Noting the well-studied link between depression and suicide, it is necessary to question giving sole responsibility of assisting patients in making end-of-life treatment decisions to these physicians. Unfortunately, the use of mental health consultation by these physicians is not a common occurrence. Greater involvement of mental health professionals in this emerging and debated area is advocated. Beyond describing mental health professionals' role in the assessment of patient competency or decision making capacity, other areas of potential involvement are described. A discussion of ethical principles relevant to this area follows, along with comments on the training necessary to adequately serve patient needs.     

Case vignette: cybertherapy

Dr. Neuro Transmitter, a psychotherapist in Paramus, New Jersey, provides services through an online, real-time consultation service known as CyberShrink, Inc., of Dallas, Texas. He is paid by the hour for his consultation services to subscribers who are billed by credit card through CyberShrink. One afternoon he logs on and is connected via private "chat channel" to a new subscriber to the service. She is Ann Hedonia of Simi Valley, California. Ten minutes into the session, Dr Transmitter recognizes that Ms. Hedonia is seriously depressed with suicidal ideation and is feeling on the edge of her ability to cope. He gently suggests that perhaps she ought to think about hospitalization near her home. Ms. Hedonia replies, "Even you don't care about me! That's it. I'm going to do it!" and disconnects. Discussion questions: Is offering psychotherapy services online ethical? What are Dr. Transmitter's obligations in general and at this particular moment to Ms. Hedonia? Suppose Ms. Hedonia has a complaint about Dr. Transmitter. From whom can she seek a remedy? Which state's laws apply regarding professional practice, confidentiality, or licensing qualifications? Must Dr. Transmitter be licensed in any state to offer this service?     

现代科学中人的问题

在控制论出现的时代,大多数科学家认为,控制的中心问题同控制的数学理论、算法理论、自动机和自动调节的研究相联系,同自组织系统的数学模式的创造相联系,有时还同应用数学的一些部门,如线性程序、实验设计等的发展相联系。另一方面,又把控制的技术手段——计算机及其工程保证和数学保证的研究列为控制科学的最重要问题。近来已经明显看     

Positive conditioned suppression: Transfer of performance between contingent and noncontingent reinforcement situations

Five homing pigeons were trained on concurrent variable-interval schedules. A fixed-duration stimulus was occasionally presented on one key; and, in various conditions, this stimulus terminated (a) without reinforcement, (b) in noncontingent reinforcement, (c) with reinforcement contingent on a response on the key on which the stimulus was presented, and (d) with reinforcement contingent on a response on the key on which the stimulus was not presented. Initially, a stimulus terminating in noncontingent reinforcement generally produced decreased response rates on both keys during the stimulus. Contingencies, however, reliably produced increased rates during the stimulus on the key on which the contingency was arranged, relative to the rate on the concurrently available key. Contingency conditions were followed by noncontingency conditions in which the separation of rates caused by contingencies was maintained. When rates during the stimulus were compared with response rates on the same keys in the absence of the stimulus, contingency-caused rate increases and decreases were again found, but only the rate decreases were maintained in subsequent noncontingency conditions. Further data suggested that the contingency-caused rate changes were not maintained when the stimulus terminated without reinforcement, and that they were unaffected by a threefold decrease in the reinforcement rate provided by the baseline schedules. The results support the suggestion that performance in the positive conditioned suppression procedure results from concurrent and multiple schedule interactions. They further suggest that the production of either acceleration or suppression is dependent on adventitious and historical contingencies.     

论库恩的《科学革命的结构》和科学发展的辩证法

本世纪六十年代资产阶级科学哲学演变的特点是同在此以前占统治地位的实证主义坚决分道扬镳。“在现代自然科学和社会科学的哲学中,主要倾向是反实证主义”——西方现代逻辑学-方法论的刊物上常常这样说。对这一现象进行历史和哲学的