The autoshaping procedure as a residual block clock

In the first experiment, 4 pigeons were each presented with a recurring sequence of four key colors followed by the delivery of grain (block clock). Once the rate of pecking had stabilized, three of the colors were replaced, during different series of sessions, by a darkening of the key. The rate of pecking was reduced within those segments of the interval between deliveries of food during which the key was dark; when the key was dark during the final portion of the interval, rates were reduced throughout the entire interval. In the second experiment, 3 new pigeons were exposed to a different sequence of colors, and the final stimulus was replaced in successive conditions by a novel color, a darkened key, and a restoration of the original color. The data indicated that darkening the key had a more severe, more extensive, and more persistent effect than did a mere change in color. These results suggest that it may be fruitful to conceptualize the autoshaping procedure as a special version of the block clock in which pecking is suppressed throughout the greater part of the interval by darkening the key. In the final condition, the same stimulus appeared in each of the last three portions of the interval. The rate of pecking was lower during the last two portions than when distinctive colors were presented, with the peak rate now appearing in the fifth of seven equal temporal components.     

Effects of reinforcer delays on choice as a function of income level

Three rats earned their daily food ration by responding during individual trials either on a lever that delivered one food pellet immediately or on a second lever that delivered three pellets after a delay that was continuously adjusted to ensure substantial responding to both alternatives. Choice of the delayed reinforcer increased when the number of trials per session was reduced. This result suggests that models seeking closure on choice effects must include a parameter reflecting how preference changes with sessionwide income. Moreover, models positing that reinforcer probability and immediacy (1/delay) function equivalently in choice are called into question by the finding that probability and immediacy produce opposing effects when income level is changed.     

Cultural practices of Hispanics: implications for the prevention of AIDS

Hispanic Americans have one of the highest rates of HIV seroprevalence among all ethnics groups in the US, with high rates being especially noticeable among women and children. Were it known which cultural factors have the most influence on whether Hispanics engage in high-risk behavior for HIV transmission, prevention interventions could be targeted accordingly. To that end, this study was mounted to identify which Hispanic cultural factors relate to condom use. 117 males and 73 females aged 17-56 years of mean age 25.67 were surveyed in Washoe county, Nevada. These mostly young adults had recently immigrated to the western US. It was initially posited that fate orientation, male- female relationships, family relationships, machismo behavior, and religion would have equal influence with respect to condom use. Analysis found that condom use was largely associated with and determined by men who are the principal buyers of condoms. A machismo attitude toward protecting women by using condoms was also associated with condom use. Neither fate orientation with respect to AIDS, nor religion were important determinants of condom use, even though 86.5% of the respondents were Catholic. The degree to which respondents adhered to traditional Hispanic cultural values was influenced by the degree of education and acculturation. On the basis of these findings, the authors suggest targeting AIDS prevention messages to males, while emphasizing the protection of women through condom use. They also suggest that both education and acculturation levels be assessed before implementing prevention programs.     

The legal consensus about foregoing life-sustaining treatment: its status and its prospects

The legal consensus that has evolved through adjudication and legislation since the Karen Quinlan case in 1976 is founded on the premise that there is a bright line between passive euthanasia and active euthanasia. Indeed, the term passive euthanasia is often eschewed in favor of less emotionally-laden terminology such as "forgoing life-sustaining treatment" or "terminating life support" so as to further sever any possible connection with active euthanasia. Legal approval has been bestowed upon passive euthanasia under certain circumstances while active euthanasia is routinely condemned. This consensus was put to a test in 1990 when the United States Supreme Court ruled on the Cruzan case. However, the Court's narrow decision did not upset the consensus, and in the most significant appellate decisions handed down by state courts since Cruzan, there has been a reaffirmation--and possibly even an extension--of the consensus. Two other threats to the legal consensus about forgoing life-sustaining treatment have begun to manifest themselves: the increasing pressure for mercy killing and "futility" cases. Both of these challenge the fundamental premises on which the consensus is grounded.     

心身问题与心灵哲学

第9届维特根斯坦国际专题讨论会的主题是心灵哲学(philosophy of mind,或译心智哲学)和心理学哲学。详细地讨论过的问题包括:心身问题、心灵哲学的传统问题和心理学哲学。 1.心身问题什么是心身问题?“心灵”(mind)一词有多种非常不同的用法,这一事实导致了现代讨论中的某种混乱。对这个词,我们至少可以区分出五种不同的用法,因此心身问题至少有五种意义。 (1)我们可以象笛卡儿使用“mens”一词那样使用“心灵”一词,让它指称具有心理属性的东西,亦即指称那种能思想,能感知,能相信和能欲求的东西。在这种情况下,我们通常是用“心灵”这个词意指“人”这个词所意指的东西,因而该词表示的就是你和我这样一些实     

20世纪末的合理性问题

近几十年,哲学家、社会学家和科学学家越来越热烈地讨论合理性问题,在科学哲学中,这个问题已成为最紧迫的问题之一。正如德国哲学家B.齐梅里写的那样,“当代大陆欧洲哲学围绕其运动的基本的和关键的问题,是合理性及其界限”。然而在大陆欧洲以外,在英美两国的出版物中,对这个问题讨论得更加活跃;在我国,许多引人注目的著述也在探讨这个问题。     

库恩的可否证性模式

库恩和拉卡托斯都不同意把理论的评价看作是理论的可证实性或理论的可否证性这一传统观点。他们的批判分为两个题目:首先,一种科学理论并非只能凭经验的结果来检验;其次,人们不会在没有现成可替代的理论时就摈弃一种理论。在拉卡托斯的术语里,要么被接受,要么被摈弃的是理论的研究纲领而不仅仅是理论本身。进一步说,某一特定的范式或研究纲领的摈弃并不就是简单地被取代,一种替代范式在另一种范式或研究纲领被摈弃之前必须发生效用。最近,人们对拉卡托斯夸大第二点进行了批判。F.M.亚克罗德认为,在科学史上有一些情况是,一项研究被简单地摈弃了,而且的确是被合理地摈弃了,尽管还没有替代者。在本文中,我     

工作负载的测量和评定

长期处于应激状态而又适应不良者可导致疾病。人类经常遇到的心理、社会性应激源除了生活事件以外,长期工作负载过重也是其中之一。本文通过对24名在监护病房工作的护士的工作负载的测量介绍了在西方国家常用的工作负载的测量和评定方法。