Reasoning about the future: Doom and Beauty

According to the Doomsday Argument we have to rethink the probabilities we assign to a soon or not so soon extinction of mankind when we realize that we are living now, rather early in the history of mankind. Sleeping Beauty finds herself in a similar predicament: on learning the date of her first awakening, she is asked to re-evaluate the probabilities of her two possible future scenarios. In connection with Doom, I argue that it is wrong to assume that our ordinary probability judgements do not already reflect our place in history: we justify the predictive use we make of the probabilities yielded by science (or other sources of information) by our knowledge of the fact that we live now, a certain time before the possible occurrence of the events the probabilities refer to. Our degrees of belief should change drastically when we forget the date—importantly, this follows without invoking the “Self Indication Assumption”. Subsequent conditionalization on information about which year it is cancels this probability shift again. The Doomsday Argument is about such probability shifts, but tells us nothing about the concrete values of the probabilities—for these, experience provides the only basis. Essentially the same analysis applies to the Sleeping Beauty problem. I argue that Sleeping Beauty “thirders” should be committed to thinking that the Doomsday Argument is ineffective; whereas “halfers” should agree that doom is imminent—but they are wrong.     

Space-time relationism in Newtonian and relativistic physics

I argue that there is natural relationist interpretation of Newtonian and relativistic non-quantum physics. Although relationist, this interpretation does not fall prey to the traditional objections based on the existence of inertial effects.     

Is Expressed Emotion a Specific Risk Factor for Depression or a Nonspecific Correlate of Psychopathology?

Five Minute Speech Sample Expressed Emotion (FMSS-EE) was examined in families of youth with depressive disorders, nondepressed youth with attention deficit/hyperactivity disorder (ADHD), and community controls screened for the absence of depression and ADHD. Consistent with the hypothesis that FMSS-EE shows some specificity as a risk factor for depression, rates of critical EE were significantly higher among mothers of youth with depression as compared to mothers of nondepressed youth with ADHD, or mothers of controls. When both mothers' and fathers' scores were used to generate family EE ratings, rates of overall EE and critical EE were significantly higher for the depressed group than the control group, but the nondepressed ADHD group did not differ significantly from the other groups. Results support the hypothesis that critical EE in mothers shows some specificity as a risk factor or correlate of depression in youth.     

Organizational Politics,Perceived Control,and Work Outcomes: Boundary Conditions on the Effects of Politics1

This investigation examined the moderating influences of perceived control (i. e., personal control and job self‐efficacy) on relationships between perceptions of organizational politics and organizational commitment, job satisfaction, intention to turnover, and job stress. Although results failed to support predictions concerning the interaction of perceptions of organizational politics and personal control, some support was found for predictions concerning the interactive influence of perceptions of organizational politics and job self‐efficacy on outcomes. Data from 189 hotel managers supported the hypothesized interactive effects of perceptions of organizational politics and job self‐efficacy for the outcomes of organizational commitment and job satisfaction. These results suggest that job self‐efficacy exacerbates the relationship between perceived politics and certain dysfunctional attitudes.     

A variable-selection heuristic for K-means clustering

One of the most vexing problems in cluster analysis is the selection and/or weighting of variables in order to include those that truly define cluster structure, while eliminating those that might mask such structure. This paper presents a variable-selection heuristic for nonhierarchical (K-means) cluster analysis based on the adjusted Rand index for measuring cluster recovery. The heuristic was subjected to Monte Carlo testing across more than 2200 datasets with known cluster structure. The results indicate the heuristic is extremely effective at eliminating masking variables. A cluster analysis of real-world financial services data revealed that using the variable-selection heuristic prior to the K-means algorithm resulted in greater cluster stability.     

Disease status in African American single mothers with HIV: the role of depressive symptoms.

The association between depressive symptoms and 2 measures of HIV disease status in 73 African American single mothers was examined. Hierarchical multiple regression analyses revealed that clinician-rated depressive symptoms predicted subjective, but not objective, parameters of disease status 12 to 14 months later. More symptoms of depression at the 1st assessment predicted an increase in physical complaints over the course of the study. Results suggest that researchers and clinicians interested in enhancing quality of life among African American single mothers with HIV infection, an understudied population within the HIV-AIDS literature, should consider both subjective and objective measures of the disease.     

Increasing volunteering at a residential facility: An experimental evaluation of a volunteer assistance program

A helpful component for comprehensive residential services for developmentally disabled persons is volunteer assistance. This investigation involved the evaluation of a program developed to increase the amount of volunteer assistance provided to a public residential facility. The program consisted of three types of related procedures: systematic volunteer recruitment steps, specific volunteer activities at the facility, and consequence/recognition for the volunteer assistance. The program was successively implemented to involve students as volunteers from two local universities, and resulted in an increase in new students volunteering from both universities. Additionally, the frequency with which the students volunteered at the residential facility increased substantially from both universities relative to control periods during which the volunteer program was not in effect. Results are discussed in terms of the benefits of volunteers and continued research to increase involvement of other prospective groups of volunteers.     

The occurrence of an increase in correlation with explicit selection

It is generally believed that correlations and standard deviations measured within an explicitly selected group must be smaller than those within an applicant population. A small data set is used to show that this is not always true, and that both validity and reliability estimates within a selected group can exceed those within the applicant population. The increase in correlation within the explicitly selected group is tied to an increase in standard deviation of the predictor in the selected group. This conclusion extends Levin's (1972) result for the case of incidental selection, selection on an unmeasured third variable. If possible, theoretical derivations should not be limited to the case where the predictor standard deviation in the applicant population exceeds that in the selected group. When such a situation occurs in observed data, it cannot be immediately dismissed as an artifact.The author would like to thank Mark L. Davison and other reviewers for their comments on earlier drafts of the paper. An anonymous reviewer provided a better example than the original one, resulting in a more general conclusion.This work was supported in part by a Dissertation Fellowship from the University of Minnesota.