The proper role of clusters in mathematical models of continuous recall

Previous research has shown that the number of words cumulatively recalled (N) at time (t) is a negatively accelerated function that reaches an asymptote as t → ∞. Research has also shown that the increase in N with t occurs in bursts or clusters. Several models purport to account for this cumulative recall curve in terms of cluster characteristics. The present research shows that previous models have not in fact successfully linked continuous recall to cluster characteristics. This research demonstrates that cluster models need to employ three empirical characteristics of clusters: T_b, the time between clusters; T_w, the average time between words within a cluster; and W_c, the number of words within a cluster. It is shown that these three quantities determine the cumulative recall curve, and these three quantities may in turn be characterized by four parameters. Of these four parameters, only three actually characterize the cumulative recall curve. Two parameters determine the initial slope and final asymptote of the curve, while a third parameter, which we introduce for the first time, characterizes the curve's shape. This latter parameter may be interpreted as the ratio ofthe time spent in retrieving and discarding a cluster that has been previously recalled to the amount of time spent in retrieving and outputting a newly encountered cluster. It is pointed out that previous success in fitting the cumulative recall data with a two-parameter function may be explained by the fact that this parameter lies in a restricted range about unity. Further experimental work is suggested to elucidate the behavior of this new parameter. Two models are then proposed to account for these characteristics of clusters and the shape of the recall curve.     

Nonmetric maximum likelihood multidimensional scaling from directional rankings of similarities

A maximum likelihood estimation procedure is developed for multidimensional scaling when (dis)similarity measures are taken by ranking procedures such as the method of conditional rank orders or the method of triadic combinations. The central feature of these procedures may be termed directionality of ranking processes. That is, rank orderings are performed in a prescribed order by successive first choices. Those data have conventionally been analyzed by Shepard-Kruskal type of nonmetric multidimensional scaling procedures. We propose, as a more appropriate alternative, a maximum likelihood method specifically designed for this type of data. A broader perspective on the present approach is given, which encompasses a wide variety of experimental methods for collecting dissimilarity data including pair comparison methods (such as the method of tetrads) and the pick-M method of similarities. An example is given to illustrate various advantages of nonmetric maximum likelihood multidimensional scaling as a statistical method. At the moment the approach is limited to the case of one-mode two-way proximity data, but could be extended in a relatively straightforward way to two-mode two-way, two-mode three-way or even three-mode three-way data, under the assumption of such models as INDSCAL or the two or three-way unfolding models.The first author's work was supported partly by the Natural Sciences and Engineering Research Council of Canada, grant number A6394. Portions of this research were done while the first author was at Bell Laboratories. MAXSCAL-4.1, a program to perform the computations described in this paper can be obtained by writing to: Computing Information Service, Attention: Ms. Carole Scheiderman, Bell Laboratories, 600 Mountain Ave., Murray Hill, N.J. 07974. Thanks are due to Yukio Inukai, who generously let us use his stimuli in our experiment, and to Jim Ramsay for his helpful comments on an earlier draft of this paper. Confidence regions in Figures 2 and 3 were drawn by the program written by Jim Ramsay. We are also indebted to anonymous reviewers for their suggestions.     

The fantasy-reality distinction in televised violence: Modifying influences on children's aggression

Fifth-grade and kindergarten boys and girls were exposed to a violent televised episode that was introduced as a fictional portrayal (fantasy condition) or as a news broadcast (reality condition). Additional groups were given no information (no-instructional-set condition) about the violent stimulus or were not exposed to the violent episode (no-TV condition). Aggressive responses and helping responses were recorded immediately following exposure. Boys were most aggressive in the reality and no-TV conditions. They were less aggressive in the noinstructional-set condition and least aggressive in the fantasy condition. In almost direct contrast, girls were most aggressive in the fantasy and no-instructional-set conditions and least aggressive in the reality and no-TV conditions. A posteriori analyses of this interaction effect revealed that girls were less aggressive than boys in the no-TV condition and in the reality condition, but not in the fantasy condition nor the no-instructional-set condition. These effects held for both older and younger children.     

Can Constructive Mathematics be Applied in Physics?

The nature of modern constructive mathematics, and its applications, actual and potential, to classical and quantum physics, are discussed.     

Does the Total Principle have any Repugnant Implications?

On the Total Principle, the best state of affairs ( ceteris paribus ) is the one with the greatest net sum of welfare value. Parfit rejects this principle, because he believes that it implies the Repugnant Conclusion, the conclusion that for any large population of people, all with lives well worth living, there will be some much larger population whose existence would be better, even though its members all have lives that are only barely worth living. Recently, however, a number of philosophers have suggested that the Total Principle does not imply the Repugnant Conclusion provided that a certain axiological view (namely, the 'Discontinuity View') is correct. Nevertheless, as I point out, there are three different versions of the Repugnant Conclusion, and it appears that the Total Principle will imply two of the three even if the Discontinuity View is correct. I then go on to argue that one of the two remaining versions turns out not to be repugnant after all. Second, I argue that the last remaining version is not, as it turns out, implied by the Total Principle. Thus, my arguments show that the Total Principle has no repugnant implications.     

Religion and the five factor model of personality: An exploratory investigation using a Canadian university sample

The purpose of the present study was to examine the relation of religion, defined in terms of religious affiliation, religious involvement and religious orientation, to the five factor model of personality as measured by the NEO Personality Inventory-Revised using a religiously heterogeneous sample of 1129 Canadian university students. Results indicate that NEO-PI-R Agreeableness and Conscientiousness domains are significantly related to and affected by religion as measured across all three operationalizations of the construct used, though some sex differences were observed. Contrary to expectation, Neuroticism was found to differ as a function of religious affiliation with persons, particularly females, reporting No Religion obtaining significantly higher scores than those persons reporting a formal religious institution for their affiliation. Findings involving Extraversion were also inconsistent with hypotheses; Extraversion did not significantly relate to any form of religion measured. Openness was found to be largely unassociated with religion except for a significant negative correlation with a measure of extrinsic religious orientation. The article concludes with a discussion of the implications of the findings in relation to existing literature and Eysenck's hypothesis that religiousness is a function of conditionability and tender-minded attitudes. Limitations of the study and suggestions for future research are also overviewed.     

Historical Origins of Argumentum ad Consequentiam

What are the historical origins of the argumentum ad consequentiam, the argument from (or literally, to) consequences, sometimes featured as an informal fallacy in logic textbooks? As shown in this paper, knowledge of the argument can be traced back to Aristotle (who did not treat it as a fallacy, but as a reasonable argument). And this type of argument shows a spotty history of recognition in logic texts and manuals over the centuries. But how it got into the modern logic textbooks as a fallacy remains somewhat obscure. Its modern genesis is traced to the logic text of James McCosh (1879).     

Profiles of Dialogue for Evaluating Arguments from Ignorance

This investigation uses the technique of the profile of dialogue as a tool for the evaluation of arguments from ignorance (also called lack-of-evidence arguments, negative evidence, ad ignorantiam arguments and ex silentio arguments). Such arguments have traditionally been classified as fallacies by the logic textbooks, but recent research has shown that in many cases they can be used reasonably. A profile of dialogue is a connected sequence of moves and countermoves in a conversational exchange of a type that is goal-directed and can be represented in a normative model of dialogue. Selected case studies are used to probe special features of using the profile technique as applied to arguments from ignorance of a kind that occur frequently in everyday conversational exchanges. One of these special features is the use of Gricean implicature. Another is the need to use negative profiles of argument.