Choice vs. Preference: The Effects of Choice and No Choice of Preferred and Non Preferred Spelling Tasks on the Academic Behavior of Students with Disabilities

The effects of choice and no choice of preferred and non preferred instructional activities on the academic behavior of 3 students with disabilities were investigated. Participant preferences for spelling tasks were assessed and an ABCDEF design was used to examine choice and preference within 6 experimental conditions: a) choice of preferred tasks, b) choice of non preferred tasks, c) no choice of preferred tasks, d) no choice of non preferred tasks, e) no choice of preferred tasks (yoked-control), and f) no choice of non preferred tasks (yoked-control). Results indicate that all 3 participants had higher levels of task engagement when working with preferred tasks, regardless of a choice or no choice format. The findings from this investigation contribute to the growing body of research that focuses on developing interventions that are responsive to individual student preferences.     

Normativity,Guardianship, and the Elderly

The concept of guardianship, its associated principles, distinctions, and articulation of the legal needs of the elderly are introduced via a review of well-canvassed criticisms of Canadian guardianship legislation. Claims that the reformed legislation of Alberta, Quebec, and British Columbia represent models of adequate adult guardianship compared with traditional (archaic lunacy) law are examined. This paper argues that these renovated models exhibit a dubious normative advance over traditional legislation. Specifically, the normative presuppositions of the reformed legislation, such as, restriction to an autonomy-paternalism framework, and the norms of the liberal individual and state, obscure important issues in at least two key areas which challenge the models' assumptions; namely, assessment and legal competence and assessment and need. The development of guardianship laws and of social arrangements that are more responsive to the life experiences of the elderly requires critical re-articulation of the nature of individuals and their communities.     

How western scrub-jays (Aphelocoma californica) select a nut: effects of the number of options, variation in nut size, and social competition among foragers

Western scrub-jays (Aphelocoma californica) often visually assess and handle several whole (unshelled) peanuts before selecting one to transport and cache; this behavior is a search for a preferred heavy nut. I repeatedly video-taped individually identifiable jays as they landed on a feeding platform and chose from presentations of peanuts that varied in the number of items or in the distribution of sizes. I examined how differences among these presentations and a bird’s social status affected the amount of assessment and the economic consequences of choice. I also examined the specific patterns of handling peanuts, called sampling, to quantify the degree to which sampling sequences were typified by repeated comparisons among sampled peanuts (retrospective sampling), or sequential assessment and rejection of peanuts (prospective sampling). Peanut assessment was more extensive and prospective when there were many options from which to choose than when there were few. Peanut assessment was more extensive and retrospective when options were similar in size than when they varied. Scrub-jays were more likely to make repeated comparisons immediately before selecting a peanut than elsewhere in a sampling sequence. Subordinate scrub-jays, who were at the greatest risk of pre-emption by competitors, assessed peanuts less extensively and were more prospective in their sampling than dominants. Unless peanuts were very similar in size, jays were more accurate at selecting a high-quality peanut and achieved a higher rate of food storage than if they had not assessed. These results show that scrub-jays can adaptively modify how they search to improve their rate of food storage, and also suggest some of the specific search tactics used by jays when assessing peanuts. Received: 26 April 1999 / Accepted after revision: 10 October 1999     

A comparison of presession and within-session reinforcement choice.

Single- and concurrent-operants procedures were used to evaluate the effects of two reinforcement conditions on the free-operant responding of 3 individuals with developmental disabilities and 1 with attention deficit disorder. In the presession choice condition, prior to each session the participant chose one item from an array of three different highly preferred stimuli. This item was delivered by the experimenter on each reinforcer delivery during that session. In the within-session choice condition, each reinforcer delivery consisted of placing an array of three different highly preferred stimuli in front of the participant, who was allowed to select one. Only one of the two reinforcement conditions was in effect for any particular session in single-operant phases. Buttons associated with each reinforcement condition were present, and the participant could allocate responses to one or the other in concurrent-operants phases. Data showed substantially more responding to the button associated with within-session choice than presession choice during concurrent-operants phases. This effect was not as apparent during single-operant phases, suggesting that a concurrent-operants procedure provided the more sensitive evaluation of within-session and presession reinforcer choice effects.     

Selecting K of N alternatives

In some decision contexts (e.g. graduate admissions) the task to select a subset of k distinct alternatives from among the N > k > 1 options available. For moderate values of N and k, the number of possible subsets of size k becomes quite large. Assuming alternatives are evaluated using consistent, though not explicit weights, selecting k, rather than 1, empirically excludes a substantial proportion (more than 80%) of the subsets; unfortunately to the unaided decision maker it is not obvious which subsets should be excluded. The tendency of subjects to select excludable subsets can be called an ‘infeasibility’ bias. The experimental evidence surprisingly shows no ‘infeasibility’ bias, as subjects overwhelmingly chose non-excluded selections.     

SOCIAL INTERACTIONS IN THREE SUPPORTED EMPLOYMENT OPTIONS: A COMPARATIVE ANALYSIS

Controversy exists over the benefits that workers with severe disabilities accrue under different supported employment options. This study focused upon one benefit of supported employment: social integration. Direct observation procedures were used to assess the social interactions of 37 adults with severe disabilities in 18 employment programs representing three different supported employment contexts (individual, enclave, and work crew). Results indicated that workers employed in individual and enclave programs had significantly more contact with nondisabled persons than did members of work crews. No differences were detected in the social contact rate between disabled and nondisabled workers in individual versus enclave sites. Furthermore, few differences in type of interactions across the three different work options were revealed. Results suggest that both individual and enclave models are capable of facilitating social integration. However, characteristics of specific job sites, more so than the employment model per se, may determine whether a particular employment setting is conducive to social integration.     

Statistical inference for multiple choice tests

Finite sample inference procedures are considered for analyzing the observed scores on a multiple choice test with several items, where, for example, the items are dissimilar, or the item responses are correlated. A discrete p-parameter exponential family model leads to a generalized linear model framework and, in a special case, a convenient regression of true score upon observed score. Techniques based upon the likelihood function, Akaike's information criteria (AIC), an approximate Bayesian marginalization procedure based on conditional maximization (BCM), and simulations for exact posterior densities (importance sampling) are used to facilitate finite sample investigations of the average true score, individual true scores, and various probabilities of interest. A simulation study suggests that, when the examinees come from two different populations, the exponential family can adequately generalize Duncan's beta-binomial model. Extensions to regression models, the classical test theory model, and empirical Bayes estimation problems are mentioned. The Duncan, Keats, and Matsumura data sets are used to illustrate potential advantages and flexibility of the exponential family model, and the BCM technique.The authors wish to thank Ella Mae Matsumura for her data set and helpful comments, Frank Baker for his advice on item response theory, Hirotugu Akaike and Taskin Atilgan, for helpful discussions regarding AIC, Graham Wood for his advice concerning the class of all binomial mixture models, Yiu Ming Chiu for providing useful references and information on tetrachoric models, and the Editor and two referees for suggesting several references and alternative approaches.     

Comparing the predictive powers of alternative multiple regression models

Mean squared error of prediction is used as the criterion for determining which of two multiple regression models (not necessarily nested) is more predictive. We show that an unrestricted (or true) model witht parameters should be chosen over a restricted (or misspecified) model withm parameters if (P _t ² ?P _m ² )>(1?P _t ² )(t?m)/n, whereP _t ² andP _m ² are the population coefficients of determination of the unrestricted and restricted models, respectively, andn is the sample size. The left-hand side of the above inequality represents the squared bias in prediction by using the restricted model, and the right-hand side gives the reduction in variance of prediction error by using the restricted model. Thus, model choice amounts to the classical statistical tradeoff of bias against variance. In practical applications, we recommend thatP ² be estimated by adjustedR ² . Our recommendation is equivalent to performing theF-test for model comparison, and using a critical value of 2?(m/n); that is, ifF>2?(m/n), the unrestricted model is recommended; otherwise, the restricted model is recommended.     

Perception: The interface between cognition and the external world

In contrast to researchers who emphasize the distinction between perception and cognition it is claimed that the perceptual system is closely intertwined with cognition and with our comprehension of the external world. This claim is supported by evidence for two characteristic features of human information processing. One of these features is the use of mental models. If mental models are assumed to be anchored in the perceptual system it will not be necessary to assume a "little man in the head" who reads off the model. Moreover, perceptually based mental models will provide a referential semantics by anchoring mentally represented concepts in the external world. The other feature is the use of perceptually based perspectives in cognition, such as actor or observer perspectives in social cognition. It is concluded that human beings consistently interact within the real world--also when they are just thinking--and that this becomes possible via perceptual processes.     

Principal component analysis with external information on both subjects and variables

A method for structural analysis of multivariate data is proposed that combines features of regression analysis and principal component analysis. In this method, the original data are first decomposed into several components according to external information. The components are then subjected to principal component analysis to explore structures within the components. It is shown that this requires the generalized singular value decomposition of a matrix with certain metric matrices. The numerical method based on the QR decomposition is described, which simplifies the computation considerably. The proposed method includes a number of interesting special cases, whose relations to existing methods are discussed. Examples are given to demonstrate practical uses of the method.The work reported in this paper was supported by grant A6394 from the Natural Sciences and Engineering Research Council of Canada to the first author. Thanks are due to Jim Ramsay, Haruo Yanai, Henk Kiers, and Shizuhiko Nishisato for their insightful comments on earlier versions of this paper. Jim Ramsay, in particular, suggested the use of the QR decomposition, which simplified the presentation of the paper considerably.