A new axiomatization of portfolio theory

An axiomatization proposed by Coombs 1974 is shown to be insufficient for the representation of gambles in a risk × expected value space as described by Portfolio Theory. A new axiom system is given which is necessary and sufficient for this representation, and which implies the old axiomatization.     

Double forced compliance: a new paradigm in cognitive dissonance theory.

An experiment was conducted with a new paradigm of Festinger's (1957) theory of dissonance. This paradigm was used to test dissonance reduction following two behaviors, rather than just one as in the classic forced compliance paradigm. The first behavior involved refraining from smoking for one evening, and the second, convincing a peer that abstinence from smoking was not difficult. It was hypothesized that the dissonance reduction effect would be greater for a sample of French students who had executed both behaviors than for those who had executed only one. The results supported this hypothesis.     

Psychological applications on the internet: A discipline on the threshold of a new millennium

The rapid developments in computers and information technology over the past decade has had an impact on psychology, which has moved in this context from local computer applications to network applications that take advantage of the Internet. This article critically reviews various psychological applications in use on the Internet, with special emphasis given to their promises and advantages as well as to their shortcomings and problems. Specifically, 10 types of psychological Internet applications are reviewed: information resources on psychological concepts and issues; self-help guides; psychological testing and assessment; help in deciding to undergo therapy; information about specific psychological services; single-session psychological advice through e-mail or c-bulletin boards; ongoing personal counseling and therapy through e-mail; real-time counseling through chat, web telephony, and videoconferencing; synchronous and asynchronous support groups, discussion groups, and group counseling; and psychological and social research. Following a discussion of ethical and related concerns, a call is voiced for intensive research and international brainstorming.     

Spanning seven orders of magnitude: a challenge for cognitive modeling

Much of cognitive psychology focuses on effects measured in tens of milliseconds while significant educational outcomes take tens of hours to achieve. The task of bridging this gap is analyzed in terms of Newell's (1990) bands of cognition—the Biological, Cognitive, Rational, and Social Bands. The 10 millisecond effects reside in his Biological Band while the significant learning outcomes reside in his Social Band. The paper assesses three theses: The Decomposition Thesis claims that learning occurring at the Social Band can be reduced to learning occurring at lower bands. The Relevance Thesis claims that instructional outcomes at the Social Band can be improved by paying attention to cognition at the lower bands. The Modeling Thesis claims that cognitive modeling provides a basis for bridging between events on the small scale and desired outcomes on the large scale. The unit‐task level, at the boundary of the Cognitive and Rational Bands, is useful for assessing these theses. There is good evidence for all three theses in efforts that bridge from the unit‐task level to educational applications. While there is evidence for the Decomposition Thesis all the way down to the 10 millisecond level, more work needs to be done to establish the Relevance Thesis and particularly the Modeling Thesis at the lower levels.     

Discrete tense logic with infinitary inference rules and systematic frame constants: A Hilbert-style axiomatization

The paper deals with the problem of axiomatizing a system 1 of discrete tense logic, where one thinks of time as the set Z of all the integers together with the operations +1 (immediate successor) and -1 (immediate predecessor). 1 is like the Segerberg-Sundholm system W1 in working with so-called infinitary inference rules; on the other hand, it differs from W1 with respect to (i) proof-theoretical setting, (ii) presence of past tense operators and a now operator, and, most importantly, with respect to (iii) the presence in of so-called systematic frame constants, which are meant to hold at exactly one point in a temporal structure and to enable us to express the irreflexivity of such structures. Those frame constants will be seen to play a paramount role in our axiomatization of 1.The present contribution reports research done under the auspices of the Swedish Council for Research in the Humanities and the Social Sciences (HSFR), project On the Legal Concepts of Rights and Duties: an Analysis Based on Deontic and Causal Conditional Logic. I wish to thank the anonymous referee for his/her extremely patient and accurate revision work, and Krister Segerberg for his helpful suggestions.     

Lowering of an auditory threshold by a near threshold warning signal

Following previous experiments on the effect of suprathreshold “warning” signals in lowering the threshold for stimuli in another modality, we have used visual “warning” signals which are themselves within the threshold range. These near threshold “warnings” appear to act in exactly the same way as suprathreshold “warnings” provided they are seen. Very weak “warnings” have a reduced effect, probably because they are not always seen. The experiment is of interest in that it supports the theory that the effect is due to the “warning” signal reducing the subject's uncertainty about when the threshold stimulus will occur, and secondly because it indicates that under these conditions at least, the subject can attend effectively to two simultaneous near-threshold stimuli.     

Fixation identification: The optimum threshold for a dispersion algorithm

It is hypothesized that the number, position, size, and duration of fixations are functions of the metric used for dispersion in a dispersion-based fixation detection algorithm, as well as of the threshold value. The sensitivity of the I-DT algorithm for the various independent variables was determined through the analysis of gaze data from chess players during a memory recall experiment. A procedure was followed in which scan paths were generated at distinct intervals in a range of threshold values for each of five different metrics of dispersion. The percentage of points of regard (PORs) used, the number of fixations returned, the spatial dispersion of PORs within fixations, and the difference between the scan paths were used as indicators to determine an optimum threshold value. It was found that a fixation radius of 1° provides a threshold that will ensure replicable results in terms of the number and position of fixations while utilizing about 90% of the gaze data captured.     

Restricted thresholds for interval orders: A case of nonaxiomatizability by a universal sentence

Let $\text{P}$_n be the class of all finite interval orders that can be interval-represented using no more than n interval lengths or threshold levels. Thus $\text{P}$₁ is the class of finite semiorders, and $\text{P}$, the union of the $\text{P}$_n, is the class of finite interval orders. While each of $\text{P}$₁ and $\text{P}$ is axiomatizable by a universal sentence in first-order logic, no $\text{P}$_n for $\text{n ≧ 2}$ is axiomatizable in the same sense.     

Pediatric do-not-attempt-resuscitation orders and public schools: a national assessment of policies and laws

Some children living with life-shortening medical conditions may wish to attend school without the threat of having resuscitation attempted in the event of cardiopulmonary arrest on the school premises. Despite recent attention to in-school do-not-attempt-resuscitation (DNAR) orders, no assessment of state laws or school policies has yet been made. We therefore sought to survey a national sample of prominent school districts and situate their policies in the context of relevant state laws. Most (80%) school districts sampled did not have policies, regulations, or protocols for dealing with student DNARs. A similar majority (76%) either would not honor student DNARs or were uncertain about whether they could. Frequent contradictions between school policies and state laws also exist. Consequently, children living with life-shortening conditions who have DNARs may not have these orders honored if cardiopulmonary arrest were to occur on school premises. Coordinated efforts are needed to harmonize school district, state, and federal approaches in order to support children and families' right to have important medical decisions honored.     

Double Margins:

No abstract available for this article.     

Limulus psychophysics: Increment threshold

Prior temporal summation work had indicated that the sensory code for certain behaviors (in bothLimulus and humans) can be understood if one suggests that the central nervous system analyzes the integral of the photoreceptor potential. An independent test of this suggestion is available because (inLimulus) the physiological increment threshold function obtained from the receptor potential integral is inflected, whereas that obtained from the initial transient peak of the receptor potential is not. The behavioral increment threshold function was measured inLimulus and found to be inflected. Fechner’s scaling assumption (that equally detectable stimulus increments are mediated by sensory signals of equal size) was supported by the fact that a theoretical function, which was calculated from the receptor integral intensity-response function by using Fechner’s scaling assumption, was able to fit the behavioral increment threshold function quite well. Furthermore, the variability of the behavioral data was proportional to the receptor integral variability. A seasonal effect was observed: Fall animals were more sensitive and had a higher criterion than winter animals. These findings permit the specification of the rerceptor potential that mediates this particular behavior at threshold: It has a steady-state amplitude of 7 mV in winter and 16 mV in fall. Taken in conjunction with the results of earlier temporal summation work indicating that the threshold receptor potential is 4.5 sec long, this specification implies that at least some behaviors are mediated by large, long sensory signals, which have properties very different from those of small, short signals, particularly with regard to both linearity and their relative dependence on time vs. energy.     

Helping traumatized warriors: Mobilizing emotions,unsettling orders

Within the span of a week in late November 2013, three Canadian Forces members committed suicide. Another suicide was reported in early December. This spate of soldiers taking their own lives caused uproar among military families and suicide survivors. Our interest in these suicides is the discourses around helping traumatized warriors and veterans that seem to be circulating both in tandem and at odds with one another. We draw on Michel Foucault's ideas about discourse, truth games, and parrhēsia to unravel some of the complicated connections within the discourse of helping traumatized soldiers. Using the analytical method of audiography, we make the case for understanding these discourses as parts of authoritative narratives and echoed narratives. We pay close attention to the embeddedness of emotion in the discursive practices of help-seeking and help-offering and to the mobilization of emotion within the asymmetries in the practice of power. We close with comments about the mediated effects of military and state hierarchies in discourses of helping traumatized warriors.     

Apparent fluctuations of a sensory threshold

An account is given of a method for the nearly continuous recording of sensory thresholds and other psycho-physical variables. Its application to the difference-threshold for sound-intensity is described. It is found that this threshold, so recorded, shows irregular fluctuations in time, excursions of up to 100 per cent, being commonly present. There is no prima facie indication of any regular periodicity in the fluctuations. No evidence was found of any general trend in amount of fluctuation throughout a half-hour period of observation. Nor, except in one subject, was there any tendency for the amount of fluctuation to increase or decrease over a series of six half-hour periods of observation. There are marked, and fairly consistent, differences between individual subjects as regards the amount and pattern of fluctuation. The possible locus and causes of these effects are briefly considered.     

Set representations of orders and a structural equivalent of saturation

Set representations are useful in the theory of knowledge spaces. A set representation of an order is an isomorphic mapping of its base set into the power set of some set ordered by set inclusion. Such a representation is basic if the union of the representing sets of the predecessors of an element contains strictly less elements than the representing set of this element, and it is parsimonious if the difference is exactly one element. This paper investigates the properties of the minimal number of elements which must be used in a parsimonious representation. This value is studied for several order operations. Moreover, orders which allow essentially only one parsimonious set representation are structurally characterized. These orders are called saturated. Finally, the way to apply these results to knowledge spaces are outlined.     

Changes in threshold level produced by a signal preceding or following the threshold stimulus

In a previous experiment (Howarth and Treisman, 1958) it was shown that when a warning preceded a stimulus by a fixed interval, the threshold level for the stimulus was higher the longer the fixed interval. A model of this effect was proposed, assuming that the threshold criterion adopted by the subject at any moment was modified by his estimate of the probability of a stimulus at that moment.

Three predictions are derived and tested. It is found that: the standard deviation of the response is constant despite the shifts in threshold induced; the threshold continues to fall as the interval from warning to stimulus is decreased to zero, with the lowest threshold when the warning signal and the stimulus are simultaneous; and that a warning signal following the stimulus by an interval of less than 0 5 to 1 sec. also lowers the threshold.     

Information and preference in partial orders: A bimatrix representation

This paper presents a bimatrix structure for examining ordinal partial rankings. A set of axioms is given similar to those of Kemeny and Snell (1962) and Bogart (1973), which uniquely determines the distance between any pair of such rankings. Thel ¹ norm is shown to satisfy this set of axioms, and to be equivalent to the Kemeny and Snell distance on their subspace of weak orderings. Consensus formation is discussed.This research was supported by a NSERC grant A8966.