The logic of viewpoints

In this paper a propositional logic of viewpoints is presented. The language of this logic consists of the usual modal operatorsL (of necessity) andM (of possibility) as well as of two new operatorsA andR. The intuitive interpretations ofA andR are “from all viewpoints” and “from some viewpoint”, respectively. Semantically the language is interpreted by using Kripke models augmented with sets of “viewpoints” and with a new alternativeness relation for the operatorA. Truth values of formulas are evaluated with respect to a world and a viewpoint. Various axiomatizations of the logic of viewpoints are presented and proved complete. Finally, some applications are given.     

Nondeterministic three-valued logic: Isotonic and guarded truth-functions

Nondeterministic programs occurring in recently developed programming languages define nondeterminate partial functions. Formulas (Boolean expressions) of such nondeterministic languages are interpreted by a nonempty subset of {T (“true”), F (“false”), U (“undefined)}. As a semantic basis for the propositional part of a corresponding nondeterministic three-valued logic we study the notion of a truth-function over {T, F, U} which is computable by a nondeterministic evaluation procedure. The main result is that these truth-functions are precisely the functions satisfying four basic properties, called \( \subseteq \) -isotonic, \( \subseteq \) ^?-isotonic, hereditarily guarded, and hereditarily guard-using, and that a function satisfies these properties iff it is explicitly definable (in a certain normal form) from “if..then..else..fi”, binary choice, and constants.     

The contribution of music vs instructions in the Musical Mood Induction Procedure

The relative contribution of the instructions and the music to the effects of the Musical Mood Induction Procedure (MMIP) were investigated. Using an experimental procedure which minimised covert experimenter bias, subjects performed under both elation and depression mood inductions in one of four conditions: music present or absent by mood change instructions present or absent, using a crossover design. Results indicated that instructions were both necessary and sufficient to produce change on mood sensitive measures. Mood change effects were reduced by controlling for the effect of subjects who responded so as not to ‘louse-up’ the experiment. The MMIP seems to be much less musical than the name implies. Further research is needed to determine which aspects of the instructions contribute most to the changes on mood sensitive measures.     

Encoding dimensions of subject-performed tasks

Summary In an experiment modelled upon the classical paradigm on release from proactive interference (PI), subjects were required to remember series of actions they had performed (e.g., roll the ball, fold the paper). The objects involved in these subject-performed tasks (SPTs) served as a basis for build-up and release of PI. The objects used in the first few trials of the experiment belonged to the same class (e.g., parts of the body), causing a build up of PI. A shift to a different class of objects (e.g., kitchen utensils) along four different dimensions (taxonomic category, weight, color, and size) was introduced to cause a release of PI. On the basis of PI-release experiments with words it was expected that shifts in taxonomic category would result in a greater release than shifts within any of the physical dimensions. However, the results revealed that the amount of PI release was, in general, larger than expected, and essentially the same for all four dimensions investigated. The results are discussed in terms of the nature of the memory representation of SPTs, and with regard to possible processing differences between SPTs and verbal information. In addition, methodological suggestions for furthering the understanding of the encoding and storage of action events are advanced.     

Measuring the quality of life: Why,how and what?

In this paper three questions concerning quality of life in medicine and health care are analysed and discussed: the motives for measuring the quality of life, the methods used in assessing it, and the definition of the concept. The purposes of the study are to find an ethically acceptable motive for measuring the quality of life; to identify the methodological advantages and disadvantages of the most prevalent current methods of measurement; and to present an approach towards measuring and defining the quality of life which evades the difficulties encountered and discussed. The analysis comprises measurements both in the clinical situation concerning individual patients and in research concerning whole populations. Three motives are found for evaluating the quality of human life: allocation of scarce medical resources, facilitating clinical decision making, and assisting patients towards autonomous decision making. It is argued that the third alternative is the only one which does not evoke ethical problems. As for the methods of evaluation, several prevalent alternatives are presented, ranging from scales of physical performance to more subtle psychological questionnaires. Clinical questionnaires are found to fail to provide a scientific foundation for universally measuring the quality of life. Finally, the question of definition is tackled. The classical distinction between need-based and want-based theories of human happiness is presented and discussed. The view is introduced and defended that neither of these approaches can be universally preferred to the other. The difficulty with the need approach is that it denies the subjective aspects of human life; whereas the problem of the want approach is that it tends to ignore some of the objective realities of the human existence. In conclusion, it is argued that the choice of methods as well as definitions should be left to the competent patients themselves — who are entitled, if they so wish, to surrender the judgement to the medical personnel. Technical factors as well as the requirements of respect for autonomy and informed consent support this conclusion.     

Modeling semantic memory: Effects of presenting semantic information in different modalities

How is semantic information from different modalities integrated and stored? If related ideas are encountered in French and English, or in pictures and sentences, is the result a single representation in memory, or two modality-dependent ones? Subjects were presented with items in different modalities, then were asked whether or not subsequently presented items were identical with the former ones. Subjects frequently accepted translations and items semantically consistent with those presented earlier as identical, although not as often as they accepted items actually seen previously. The same pattern of results was found when the items were French and English sentences, and when they were pictures and sentences. The results can be explained by the hypothesis that subjects integrate information across modalities into a single underlying semantic representation. A computer model, embodying this hypothesis, made predictions in close agreement with the data.