Testing for selectivity in the dependence of random variables on external factors

Random variables A and B, whose joint distribution depends on factors (x,y), are selectively influenced by x and y, respectively, if A and B can be represented as functions of, respectively, (x,S_A,C) and (y,S_B,C), where S_A,S_B,C are stochastically independent and do not depend on (x,y). Selective influence implies selective dependence of marginal distributions on the respective factors: thus no parameter of A may depend on y. But parameters characterizing stochastic interdependence of A and B, such as their mixed moments, are generally functions of both x and y. We derive two simple necessary conditions for selective dependence of (A,B) on (x,y), which can be used to conduct a potential infinity of selectiveness tests. One condition is that, for any factor values x,x^′ and y,y^′,

s_xy≤s_xy^′+s_x^′y^′+s_x^′y,     

Overt and Hidden Processes in 20th Century Music

For the purpose of contributing to a clarification of the term “process”, different kinds of musical processes are investigated: A rule-determined phase shifting process in Steve Reich's Piano Phase (1966), a model for an indeterminate composition process in John Cage's Variations II (1961), a number of evolution processes in György Ligeti's In zart fliessender Bewegung (1976), and a generative process of fractal nature in Per Nørgård's Second Symphony (1970). In conclusion I propose that six process categories should be included in a typology of processes: Rule-determined, goal-directed and indeterminate transformation processes, and rule-determined, goal-directed and indeterminate generative processes.     

Effect of family environment and donor source on patient quality of life following renal transplantation.

The authors examined the degree to which the supportiveness of a patient's family environment predicts change in quality of life following renal transplantation. The sample consisted of 95 patients receiving renal grafts from either a living donor or a cadaveric donor. Patients were initially assessed prior to transplantation with follow-up assessment occurring an average of 5.5 months after transplantation. Among patients receiving a living-donor kidney, those reporting a more supportive family environment exhibited reduced depression, improved mobility, and improved social functioning. However, those living-donor recipients reporting less family support exhibited increased depression and diminished mobility and social functioning after transplantation. Patients receiving a kidney from a cadaveric donor showed modest improvements in quality of life regardless of the degree of family support.     

Testing unidimensionality in polytomous Rasch models

A fundamental assumption of most IRT models is that items measure the same unidimensional latent construct. For the polytomous Rasch model two ways of testing this assumption against specific multidimensional alternatives are discussed. One, a marginal approach assuming a multidimensional parametric latent variable distribution, and, two, a conditional approach with no distributional assumptions about the latent variable. The second approach generalizes the Martin-Löf test for the dichotomous Rasch model in two ways: to polytomous items and to a test against an alternative that may have more than two dimensions. A study on occupational health is used to motivate and illustrate the methods.The authors would like to thank Niels Keiding, Klaus Larsen and the anonymous reviewers for valuable comments to a previous version of this paper. This research was supported by a grant from the Danish Research Academy and by a general research grant from Quality Metric, Inc.     

A new definition of well-behaved discrimination functions

A discrimination function shows the probability or degree with which stimuli are discriminated from each other when presented in pairs. In a previous publication [Kujala, J.V., & Dzhafarov, E.N. (2008). On minima of discrimination functions. Journal of Mathematical Psychology, 52, 116–127] we introduced a condition under which the conformity of a discrimination function with the law of Regular Minimality (which says, essentially, that “being least discriminable from” is a symmetric relation) implies the constancy of the function’s minima (i.e., the same level of discriminability of every stimulus from the stimulus least discriminable from it). This condition, referred to as “well-behavedness,” turns out to be unnecessarily restrictive. In this note we give a significantly more general definition of well-behavedness, applicable to all Hausdorff arc-connected stimulus spaces. The definition employs the notion of the smallest transitively and topologically closed extension of a relation. We provide a transfinite-recursive construction for this notion and illustrate it by examples.     

Regular Minimality and Thurstonian-type modeling

A Thurstonian-type model for pairwise comparisons is any model in which the response (e.g., “they are the same” or “they are different”) to two stimuli being compared depends, deterministically or probabilistically, on the realizations of two randomly varying representations (perceptual images) of these stimuli. The two perceptual images in such a model may be stochastically interdependent but each has to be selectively dependent on its stimulus. It has been previously shown that all possible discrimination probability functions for same–different comparisons can be generated by Thurstonian-type models of the simplest variety, with independent percepts and deterministic decision rules. It has also been shown, however, that a broad class of Thurstonian-type models, called “well-behaved” (and including, e.g., models with multivariate normal perceptual representations whose parameters are smooth functions of stimuli) cannot simultaneously account for two empirically plausible properties of same–different comparisons, Regular Minimality (which essentially says that “being least discriminable from” is a symmetric relation) and nonconstancy of the minima of discrimination probabilities (the fact that different pairs of least discriminable stimuli are discriminated with different probabilities). These results have been obtained for stimulus spaces represented by regions of Euclidean spaces. In this paper, the impossibility for well-behaved Thurstonian-type models to simultaneously account for Regular Minimality and nonconstancy of minima is established for a much broader notion of well-behavedness applied to a much broader class of stimulus spaces (any Hausdorff arc-connected ones). The universality of Thurstonian-type models with independent perceptual images and deterministic decision rules is shown (by a simpler proof than before) to hold for arbitrary stimulus spaces.     

TESTIMONY,MEMORY AND THE LIMITS OF THE A PRIORI

Philosophical Studies -     

Parental characteristics and interactional dysfunction in families with child behavior problems: A preliminary investigation

Thirty-six families with a preteenage behavior problem child were assessed on measures of marital discord, parental psychopathology, and three parental cognitive factors: knowledge of behavioral principles, tolerance for child deviancy, and expectations regarding their child's behavior. Nine nonproblem families with demographic characteristics similar to the problem families were also assessed. Correlational analyses across all families revealed a strong association between marital discord and the parental index of child behavior problems. While a number of significant associations were discovered between the various measures of marital discord, parental psychopathology, and parental cognitive factors, no other measure besides marital discord was associated with parental perception of child behavior problems. The nonproblem families and 15 of the problem families also participated in home observations obtained through random audio recordings during high interaction periods. These observational data indicated a significant relationship between parental perception of child behavior problems and parental negative behavior toward the child, but no significant relationship between parental perception of child behavior problems and child behavior, even when child behavior was weighted by parents' reactions to that behavior. Through sequential analysis, several contingent relations between parent and child behavior were discovered. Findings are discussed in relation to family systems theory.     

The relationship between treatment exposure times and changes in stuttering frequency during contingent stimulation

Four adult stutterers were exposed to 60 consecutive minutes of verbal contigent stimulation. In each session subjects spoke until a stuttering frequency stability criterion was met (baserate) followed by 60 min of exposure to the word wrong presented contingently upon each instance of stuttering. The data were analyzed according to changes in stuttering which occured following 20, 40, and 60 min of treatment exposure. The results revealed that stuttering frequency was reduced for all subjects during all three 20-min segments of the treatment condition. The only significant reductions in stuttering frequency, however, occured within the first 20 min of treatment.     

Children's perceptions of parental behaviors

Children's perceptions of positive and negative parental behaviors were assessed using a newly-developed scale, the Parent Perception Inventory (PPI). Reliability and validity were examined across a sample of 75 children aged 5 to 13 using additional measures administered to the children and measures completed by their parents. The scale showed acceptable levels of internal consistency. No effects of children's age were apparent, but effects of the child's and parent's gender were found. Boys reported more positive parental behaviors, particularly for fathers, and children reported more negative (disciplinary) behaviors by mothers. PPI scores were predictably related to child's self-concept and behavior problems (convergent validity) and generally unrelated to measures of child's achievement (discriminant validity). As predicted by family systems theory, children from nondistressed families viewed their parents as behaving more similarly on the PPI than did children from distressed families.