Preference for signaled over unsignaled shock schedules: Ruling out asymmetry and response fixation as factors

Experiment 1 tested whether a “symmetrical” choice procedure yields results different from those previously reported using the “unidirectional” standard changeover procedure (e.g., Badia & Culbertson, 1972). Subjects could change at any time from unsignaled to signaled shock by pressing a lever and from signaled to unsignaled shock by pressing a second lever. Results were identical to those of the standard procedure and showed that the standard procedure is fully adequate. Experiment 2 tested whether choice of high density signaled shock over low-density unsignaled shock (Badia, Coker, & Harsh, 1973) resulted from initial training with equal-density schedules. Subjects were trained and tested with signaled shock twice as dense as unsignaled shock. Three of four subjects strongly preferred the signaled condition, thus ruling out carry-over and “response fixation” as alternative explanations.     

Experiences extended across time: Evaluation of moments and episodes

Intuitions relating to outcomes extended over time are examined. Utility integration is proposed as a normative rule for the evaluation of extended episodes. In Experiment 1, subjects explicitly compared aversive experiences of varying durations. By several measures, disutility was a marginally decreasing function of episode duration, even for experiences that were thought to become increasingly aversive. This pattern is a qualitative violation of the integration rule. In Experiment 2, subjects made global evaluations of a hypothetical person's aversive experiences, on the basis of a series of subjective ratings of discomfort made at periodic intervals. The results showed an extreme sensitivity to improving or deteriorating trend and a striking neglect of duration. The final moments of an extended episode appear to exert a strong influence on the overall judgment. This leads to violations of monotonicity when adding some moments of moderate pain reduces judgments of global aversiveness.     

External analyses of preference models

Using Carroll's external analysis, several studies have found that unfolding models account for more, although seldom significantly more, variance in preferences than Tucker's vector model. In studies of sociometric ratings and political preferences, the unfolding model again rarely outpredicted the vector model by a significant amount. Yet on cross-validation, the unfolding model consistently accounted for more variance. Results suggest that sometimes significance tests are less sensitive than cross-validation procedures to the small but consistent superiority of the unfolding model. Future researchers may wish to use significance tests and cross-validation techniques in comparing models.     

On a metric,unidimensional unfolding model for attitudinal and developmental data

If stimulus responses are linearly related to squared distances between stimulus scale values and person scores along a latent continuum, (a) the stimulus × stimulus correlation matrix will display a simplex-like pattern, (b) the signs of first-order partial correlations can be specified in an empirically testable manner, and (c) the variables will have a semicircular, two-factor structure. Along the semicircle, variables will be ordered by their positions on the latent dimension. The above results suggest procedures for examining the appropriateness of the model and procedures for ordering the stimuli. Applications to developmental and attitudinal data are discussed. This research was supported by a grant from the Graduate School of the University of Minnesota to the author and by a grant from the U. S. Public Health Service (Grant No. 1-R01-MH27861-01) to Dr. James Rest, Principal Investigator.     

Answer Sets and Qualitative Optimization

One of the major reasons for the success of answer set programmingin recent years was the shift from a theorem proving to a constraintprogramming view: problems are represented such that stablemodels, respectively answer sets, rather than theorems correspondto solutions. This shift in perspective proved extremely fruitfulin many areas. We believe that going one step further from a"hard" to a "soft" constraint programming paradigm, or, in otherwords, to a paradigm of qualitative optimization, will proveequally fruitful. In this paper we try to support this claimby showing that several generic problems in logic based problemsolving can be understood as qualitative optimization problems,and that these problems have simple and elegant formulationsgiven adequate optimization constructs in the knowledge representationlanguage.     

Body image and size perceptions of Mexican American women

Purpose was to examine in Mexican American women the influences of age, weight, socioeconomic status and acculturation level on body image, perceptions of attractive and acceptable female shapes, and tolerance for overweight and obesity. Participants were 276 Mexican American women. Age, body mass index, socioeconomic status, and acculturation level were measured. The Figure Rating Scale was used to assess body image, preferences for body size, and perceptions of underweight to obese and acceptable body sizes. Significant effects for acculturation level and current weight were found. Women who were more Anglo oriented showed greater preference for thinner figures. As compared to normal weight women, obese women chose larger figures as ideal, realistic, attractive, and thinnest acceptable. Findings point to the impact of acculturation and obesity on body image and size perceptions. Health professionals working with Mexican Americans should consider each individual's current weight and level of acculturation.     

Effects of Participant’s Choice of Different Digital Interventions on Outcomes for Binge-Spectrum Eating Disorders: A Pilot Doubly Randomized Preference Trial

It is unclear whether offering individuals a choice between different digital intervention programs affects treatment outcomes. To generate initial insights, we conducted a pilot doubly randomized preference trial to test whether offering individuals with binge-spectrum eating disorder a choice between two digital interventions is causally linked with superior outcomes than random assignment to these interventions. Participants with recurrent binge eating were randomized to either a choice (n = 77) or no-choice (n = 78) group. Those in the choice group could choose one of the two digital programs, while those in the no-choice group were assigned a program at random. The two digital interventions (a broad and a focused program) took 4 weeks to complete, were based on cognitive-behavioral principles and have demonstrated comparable efficacy, but differ in scope, content, and targeted change mechanisms. Most participants (79%) allocated to the choice condition chose the broad program. While both groups experienced improvements in primary (Eating Disorder Examination Questionnaire global scores and number of binge eating episodes over the past month) and secondary outcomes (dietary restraint, body image concerns, etc.), no significant between-group differences were observed. The two groups did not differ on dropout rates, nor on most indices of intervention engagement. Findings provide preliminary insights towards the role of client preferences in digital mental health interventions for eating disorders. Client preferences may not determine outcomes when digital interventions are based on similar underlying principles, although larger trials are needed to confirm this.     

Multidimensional unfolding analyses of ranking data for groups

One probabilistic version of Coombs' unfolding model called the MMUR (Marginalization model for the Multidimensional Unfolding analysis of Ranking data) is extended to treat ranking data for groups. One favorable feature of the model is that it can both take into consideration individual differences without estimating the subject parameters and capture the differences between the groups in a systematic manner. Another advantage lies in the fact that one can see the group differences in the geometrical point configuration, since the model shows how the ideal points of the groups differ from each other in space. Four applications are provided which demonstrate that the model is useful for clarifying systematic differences in this type of data.     

A COMPARISON OF REINFORCER ASSESSMENT METHODS: THE UTILITY OF VERBAL AND PICTORIAL CHOICE PROCEDURES

We compared three methods of stimulus preference assessment for verbal children and specifically evaluated the utility of a verbal choice procedure for assessing relative reinforcer value. Using a token system, relative preference for five categories of reinforcers, representing 15 different stimuli, was assessed by three methods: a reinforcer survey, a verbal stimulus-choice questionnaire, and a pictorial stimulus-choice procedure. Results showed that the verbal and pictorial stimulus-choice assessments accurately identified high- and low-preference categories for 3 of 4 participants. Survey results alone often rated multiple categories as high preference, were less likely to identify low-preference categories, and were less likely to correspond with the results of a reinforcer assessment.     

Children’s developing views of social excluders: A dissociation between social evaluation and partner preference

When facing social exclusion, children seek to strengthen existing social connections and form new ones. This study asked whether they also make strategic choices about the targets of their affiliative goals. Three- to six-year-olds (N = 69; 36 female; mostly non-Hispanic White) observed characters acting inclusively or exclusively. All ages viewed excluders more negatively than includers, but only five- and six-year-olds preferred includers as play partners. Despite easily detecting and remembering exclusion events, younger children expressed no play partner preference. Children's verbal justifications revealed that older children choose partners more carefully and draw on a richer understanding of exclusion. More generally, the initial dissociation between social evaluation and preference formation underscores that these are distinct processes with different developmental trajectories.