What is learned from experience in a probabilistic environment?

Three experiments explored what is learned from experience in a probabilistic environment. The task was a simulated medical decision‐making task with each patient having one of two test results and one of two diseases. The test result was highly predictive of the disease for all participants. The base rate of the test result was varied between participants to produce different inverse conditional probabilities of the test result given the disease across conditions. Participants trained using feedback to predict a patient's disease from a test result showed the classic confusion of the inverse error, substituting the forward conditional probability for the inverse conditional probability when tested on it. Additional training on the base rate of the test result did little to improve performance. Training on the joint probabilities, however, produced good performance on either conditional probability. The pattern of results demonstrated that experience with the environment is not always sufficient for good performance. That natural sampling leads to good performance was not supported. Further, because participants not trained on joint probabilities did, however, know them but still committed the confusion of the inverse error, the hypothesis that having joint probabilities would facilitate performance was not supported. The pattern of results supported the conclusion that people learn all the necessary information from experience in a probabilistic environment, but depending upon what the experience was, it may interfere with their ability to recall to memory the appropriate sample set necessary for estimating or using the inverse conditional probability. Copyright © 2004 John Wiley & Sons, Ltd.     

Stimulus control and associative learning.

Interest in operant research on stimulus control has declined at the same time that much interest has burgeoned in nonoperant areas. Several examples of this shift toward traditional learning theory are considered, all of which have sponsored theoretical approaches that attempt to characterize the underlying associative units. These theoretical approaches are defended on the grounds that they have generated a deeper understanding of a variety of often puzzling phenomena. My projection is that future research will be determined even more strongly by theories about the structure of associations. Particular issues for which such discussion will have major impact include (1) whether conditional stimulus control is qualitatively different than simpler forms of stimulus control, (2) whether stimulus control is organized hierarchically, and (3) the origin of categories of stimulus equivalence.     

内容和形式对毒品成瘾者条件推理的影响

本研究通过比较推理内容与推理形式对毒品成瘾者推理成绩的影响,以探究影响毒品成瘾者能力成绩的主要内在机制。实验采用了2(四卡片形式vs选择项形式)×2(描述性规则vs社会契约规则)混合设计,以240名男性戒毒人员为研究对象,考察他们在不同推理内容与不同推理形式下的条件推理作业成绩。结果发现:(1)就规则内容来看,描述性规则内容在选择项形式上的得分好于四卡片形式,社会契约规则内容在两种呈现形式下的成绩没有显著差异;(2)就规则呈现形式来看,四卡片形式下的描述性规则得分显著地低于社会契约规则得分; 选择项形式下两类规则内容得分无显著差异。结果表明:毒品成瘾者的条件推理行为既受到推理内容的影响,也受到逻辑规则呈现形式的影响。