Structural alterations of an ambiguous musical figure: the scale illusion revisited.

The scale illusion (Deutsch, 1975) shows the importance of frequency range in the perceptual organization of a sequence of notes. This paper includes three experiments on the scale illusion. Experiments 1 and 2 demonstrated that if the structure of the pattern of notes used in the original scale illusion study is altered slightly, by adding or subtracting a pair of notes from the ends of the sequence, there is a significant decrease in the rate of frequency-based responses, suggesting a weaker illusion. Experiment 3 investigated two features of the note patterns that may have led to this change. Specifically, it asked whether the decrease in the strength of the illusion is due to (1) the nature of the notes at the extremes of the frequency range and/or (2) the nature of the notes at the crossing point of the two scales. While both sources were found to affect the strength of the scale illusion, the former had a greater influence.     

Affect and persuasion: Mood effects on the processing of message content and context cues and on subsequent behaviour

Two experiments are reported examining the impact of recipients' mood on the processing of simple, everyday persuasive communications and on subsequent behaviour. Consistent with the general assumption that affective states may inform an individual about the state of its current environment, it was found that positive (as compared to neutral or negative) mood reduced subjects' motivation to systematically process both content information and contextual cues. Specifically, Experiment I demonstrated that, in a field setting, the behaviour of subjects who had been put in a good mood was less likely to reflect differences in message content than the behaviour of neutral mood subjects. Experiment 2 replicated and extended these findings, showing that good mood subjects' behaviour was uninfluenced by content as well as context information, whereas bad mood subjects did make use of both types of information. Subject's cognitive responses and evaluations paralleled the behavioural data. The results are discussed in terms of their compatibility with contemporary models of persuasion, and their implications for future research on mood and persuasion and on the interplay of affect and cognition in general are considered.     

Neurochemical knowledge in electroconvulsive therapy (ECT)

The paper is concerned with an attempt to generalize and categorize current hypotheses on the biochemical basis of ECT. The hypotheses are critically evaluated with respect to the relevance of their experimental fundamentals. Thus, certain hypotheses are valid only in a qualified sense. Particular interest is focussed on those conceptions which try to correlate ECT-induced changes in synaptic receptor sensitivities (up-/down-regulation) with super- resp. subsensitivity hypotheses of psychoses. In this connection, noradrenergic and opioid systems on the one hand, and the axis hypothalamus-hypophysis on the other hand seem to play a dominant role.     

Isotonic ordinal probabilistic models (ISOP)

The concept of an ordinal instrumental probabilistic comparison is introduced. It relies on an ordinal scale given a priori and on the concept of stochastic dominance. It is used to define a weakly independently ordered system, or isotonic ordinal probabilistic (ISOP) model, which allows the construction of separate sample-free ordinal scales on a set of subjects and a set of items. The ISOP-model is a common nonparametric theoretical structure for unidimensional models for quantitative, ordinal and dichotomous variables.Fundamental theorems on dichotomous and polytomous weakly independently ordered systems are derived. It is shown that the raw score system has the same formal properties as the latent system, and therefore the latter can be tested at the observed empirical level.I wish to thank 3 reviewers and 2 editors who contributed a lot to the readability and precision of the article.     

The effect of uncertainty on the detection of frequency modulation at low modulation rates

Frequency modulation detection performance is compared in two conditions of stimulus variability. The data show that when the modulation rate is randomized within an experimental block, performance is somewhat poorer than when the modulation rate is fixed. The results are interpreted within the framework of a template matching model for modulation detection. They suggest that a template is acquired in part from experimental context and in part from a multistage template matching process.     

Considerations in the choice of interobserver reliability estimates

Two types of interobserver reliability values may be needed in treatment studies in which observers constitute the primary data-acquisition system: trial reliability and the reliability of the composite unit or score which is subsequently analyzed, e.g., daily or weekly session totals. Two approaches to determining interobserver reliability are described: percentage agreement and "correlational" measures of reliability. The interpretation of these estimates, factors affecting their magnitude, and the advantages and limitations of each approach are presented.     

Family perception of interpersonal behavior as a predictor in eating disorders: a prospective, six-year followup study

This study assessed family perception patterns of interpersonal behavior in families with a daughter diagnosed with an eating disorder 6 years after treatment that used a prospective design. Family perception patterns of patients found to have a poor outcome at followup (n = 15) were compared with patients with a good outcome (n = 23), as well as a control group (n = 36). Using the system of multiple level observation of groups (SYMLOG), all 238 family members evaluated themselves and each other. The index patients with a poor outcome perceived themselves as friendlier and more positive than they were perceived by their families. In comparison to parents of daughters with a good outcome and the control group, parents of daughters in the poor outcome group perceived themselves to be less friendly than their partners perceived them to be. A rigid polarization of the perception of the index patient by family members and a discrepancy in this perception between the index patient and the rest of the family were found to be indicative of a poor prognosis. Implications for treatment based on family perception patterns of interpersonal behavior are discussed.     

Nonparametric IRT: Testing the bi-isotonicity of isotonic probabilistic models (ISOP)

Nonparametric tests for testing the validity of polytomous ISOP-models (unidimensional ordinal probabilistic polytomous IRT-models) are presented. Since the ISOP-model is a very general nonparametric unidimensional rating scale model the test statistics apply to a great multitude of latent trait models. A test for the comonotonicity of item sets of two or more items is suggested. Procedures for testing the comonotonicity of two item sets and for item selection are developed. The tests are based on Goodman-Kruskal's gamma index of ordinal association and are generalizations thereof. It is an essential advantage of polytomous ISOP-models within probabilistic IRT-models that the tests of validity of the model can be performed before and without the model being fitted to the data. The new test statistics have the further advantage that no prior order of items or subjects needs to be known.