Indefinite probability statements

Conclusion Indefinite probability statements can be analysed in terms of statements which attribute probability to propositions. Therefore, there is no need to find a special place in probability theory for them; once we have an adequate account of statements that straightforwardly attribute probability to propositions, we will automatically have an adequate account of indefinite probability statements.     

An analysis of visual detection by temporal probability summation

The probability of detection by temporal probability summation (TPS) is derived assuming a non-white Gaussian noise process, characterised by a finite second spectral moment λ₂; the assumption of stationary noise is discussed with respect to neurophysiological findings suggesting multiplicative noise for individual neurons. The usual white-noise assumption is shown to imply inconsistent detection models. d^′-estimates for 2AFC-experiments do not depend on the value of λ₂ and do not differ from those derived from the standard SDT-assumptions, in contrast to d^′-estimates for yes-no-experiments, which depend on the probability of false alarms. Estimates of properties of a visual channel depend on whether detection is by TPS or temporal peak detection (TPD); it is argued that TPD is not a special case of TPS, and that subjects chose a TPS- or a TPD-strategy depending on experimental conditions.     

A postulate-based analysis of comparative preference statements

There has been a growing interest in the study of preferences for their utility in solving problems related to decision making. Most of the preference representation languages developed in the literature are based on comparative preference statements since they offer a simple and intuitive way for expressing preferences. They can be further interpreted following different semantics, imparting a greater flexibility on how outcomes can be compared. So far the main objective has been to rank-order the set of outcomes given a set of comparative preference statements and one or several semantics. Tackling this problem from a different angle, we look into the behavioural aspects of the preference semantics and statements by attempting to formalise the intuition behind them using postulates studied in preference logics and non-monotonic reasoning. We select the postulates w.r.t. three criteria: coherence, syntax independence and inference. Thus, our analysis provides a means to determine those properties that are satisfied for a given preference semantics.     

Incompatibility statements

In the context of worlds with infinitely many bearers of utility, we argue that several collections of natural Utilitarian principles--principles which are certainly true in the classical finite Utilitarian context and which any Utilitarian would find appealing--are inconsistent.     

An optimum value for detection probability

In many psychoacoustic experiments, an experimenter wishes to determine the effects of one or more treatments Ito the subjects, or to the stimuli, or to both) with as little experimental labor as possible. The experimenter is often able to control the similarity of the stimuli and is thus free to choose a base level of performance before the treatment is applied. On the basis of the model presented in this paper, the base level of performance that best enables any change in performance due to the treatment to be detected is predicted. A relatively high base-level performance of 95% correct discrimination results from the model, although practical constraints may dictate a somewhat lower value. An experiment (involving pitch discrimination) that provides data supporting the model is also reported. The model is applicable only to the two-alternative/forced-choice experimental paradigm.     

Self-Monitoring negative statements

We examined the effects of a self-monitoring program on reducing the frequency of negative statements of a student with mild mental retardation who was enrolled in a self-contained classroom at a middle school. A changing criterion design was used within a multiple baseline design across two classroom periods. Additionally, the frequency of positive statements was reported. The results showed a decrease in the number of negative statements, and an increase in the number of positive statements. Maintenance data collected up to 8 weeks after the program ended indicated that the student continued to emit positive rather than negative statements. The use of this procedure to decelerate undesirable behavior is discussed.     

An evidential support accumulation model of subjective probability

A model of cue-based probability judgment is developed within the framework of support theory. Cue diagnosticity is evaluated from experience as represented by error-free frequency counts. When presented with a pattern of cues, the diagnostic implications of each cue are assessed independently and then summed to arrive at an assessment of the support for a hypothesis, with greater weight placed on present than on absent cues. The model can also accommodate adjustment of support in light of the baserate or prior probability of a hypothesis. Support for alternatives packed together in a "residual" hypothesis is discounted; fewer cues are consulted in assessing support for alternatives as support for the focal hypothesis increases. Results of fitting this and several alternative models to data from four new multiple-cue probability learning experiments are reported.     

Consequence analysis: Its effects on verbal statements about an environmental project

Typically, citizens lack relevant information concerning possible consequences of proposed environmental projects. Despite federal requirements for citizen participation in decisions about proposed roadway projects, no systematic procedures exist for educating citizens as to the possible consequences of such projects. The effects of a consequence analysis procedure on community residents' verbal statements about the favorability of a proposed roadway project were assessed. The consequence analysis procedure involved asking residents to rate the desirability and magnitude of each of 48 possible consequences of the proposed roadway project. Following the intervention, overall ratings of favorability of the project changed for nine of ten residents. Community residents' ratings of the quality of participants' justifications of their position on the roadway issue provided evidence of generalization to this collateral behavior.     

An efficient procedure for selecting equal probability samples

FORTRAN code that implements an algorithm for selecting equal probability samples is given. The procedure is brief and decides to include or not include a record as it is called. Consequently, storage requirements are minimal. The procedure gives the exact number of values specified, with each record in the population having an equal probability for inclusion in the sample, including the last.     

On validating observation statements

Summary The author discusses various concepts of observation statements, subjecting to closer examination that concept according to which an observation statement is a statement with all terms interpreted directly. The logical analysis of direct interpretation, identified with the so called ostensive definition, results in the conclusion that the denotation of predicates is determined by this procedure in a very slight degree. Consequently, observation statements affirming a predicate so interpreted of objects not identical with the standard objects referred to in the ostensive definition cannot be validated.