Effects of stimulus-response uncertainty on watchkeeping performance and choice reactions

The present study was conducted to assess the effects of S-R uncertainty on performance in watchkeeping and typical type-b choice-reaction situations. The assessment was based in part on measurements of S-R compatibility effects in the two performance conditions. Four levels of S-R uncertainty (1, 2, 3 and 4 bits/S-R event) were combined factorially with two levels of S-R compatibility (high and low) and the two kinds of tasks (watchkeeping and choice-reaction); 12 Ss were assigned at random to each of the 16 conditions. A matrix of lights was used as stimuli in the choice-reaction condition; Ss monitored the matrix for a I-h duration in the watchkeeping condition. In both tasks, Ss responded by pressing a corresponding key after the presentation of a stimulus or “critical signal.” Reaction time (RT) was found to be an increas ing linear function of S-R uncertainty in both tasks. and the effects of S-R compatibility were essentially identical in the two. However, choice reactions were significantly faster than watchkeeping responses, and the rate of gain of information in watchkeeping was greater than in the comparable choice-reaction situations. The results are interpreted as supporting the hypothesis that watchkeeping differs from the simpler choice-reaction task principally in presenting an additional source of (temporal) uncertainty for information processing.     

Effects of discriminability and irrelevant information on absolute judgments’

The effects of irrelevant information (0, 1, 2, or 3 bits stimulus) on absolute judgments of size were measured at different levels of discrimination difficulty. The stimuli were 7 small circular spots of light of different sizes, selected from an eaual-discriminability scole, and arranged into 6 pairs that represented different levels of stimulus dissimilarity. Three of the pairs comprised a low-dissimilarity (LD) subgrouping in which different lepels of dissimilarity and discriminability were confounded, whereas the remaining three pairs comprised a high-dissimilarity (HD) subgrouping in which different levels of dissimilarity occurred at a single high level of discriminability. Different colors were used to provide the four levels of irrelevant information; 240 Ss (10 in each of the 24 experimental conditions) made absolute judgments of size under the classical procedure for the method of single stimuli. Separate analyses of errors, reaction times, and rates of information transmission indicated that irrelevant information had an increasingly detrimental effect on absolute judgments as discrimination difficulty was increased (in the LD subgroup), but essentially no effect where discriminations were easily modefin the HD subgroup).     

Factual Evidence without Knowledge

A central function of our evidence is to constrain the epistemic rationality of our propositional attitudes. Our knowledge does this. That fact supports Timothy Williamson's contention that our evidence is identical to our knowledge, ‘E=K’. But it is argued here that some true propositions are evidence without being known. Some of them cannot be known; others are contingently not known. Propositions play the rational role of evidence whenever they are clearly true, whether or not they are known.     

Reviews of current books

Pastoral Psychology -     

Chronic pain, meaning, and spirituality: A qualitative study of the healing process in relation to the role of meaning and spirituality

This qualitative study explores experiences of individuals with chronic pain in their attempt to find meaning in the presence of continual pain. Fifteen participants at Loma Linda University Behavioral Medicine Center were interviewed. Emerging themes from this study show that (1) meaning is initially defined as the ability to engage in productive activities and positive relationships; (2) chronic pain is perceived as the factor that removes meaning from the lives of sufferers; (3) medication is used to cope with pain, leading to addiction; (4) addiction results in greater loss of meaning; and (5) rediscovery of meaning takes place through a more complex understanding of the self that embraces suffering and thus is able to explain the interrelation of pain, emotions, and addiction. A change in self-understanding makes the reintegration of meaning possible.     

分类中相似性的理论与模型

相似性在分类的原型理论、样例理论、定义理论和理论解释观中都扮演着重要的角色。人们对相似性的研究由来已久,但是它在分类的领域中至今仍是一个相对模糊的概念,这部分地由于揭示相似性的真正机制将涉及到复杂的信息加工过程。本文以分类中的相似性为出发点介绍了近期相似性研究的一些理论与模型并在此基础上对概念和分类领域中的相似性研究进行了分析和总结。