Adjunctive behavior of the rat under periodic food delivery in a 24-hour environment

The behavior of 4 rats living in complex environments was monitored 24 h per day during free-feeding baseline and under conditions of periodic access to food. Under the periodic schedules, the minimum interfood interval (IFI) was increased from 16 to 512 sec in an ascending series. Periodic food produced robust overall increases in investigation of the feeder, drinking, general activity, and rearing, but not in wheel-running. The temporal distribution of behavior within the IFI was similar across subjects and supported the hypothesis that some responses were largely time-locked to the period immediately following eating, while other responses expanded to fill the interval. However, these response differences were not adequately captured by present classification schemes. Finally, the distribution of drinking following a food pellet strongly resembled the distribution of drinking following bouts of feeding in baseline. The results suggest that adjunctive behavior stems from three sources: (1) a simple increase in the number of opportunities for expression of normal preprandial and postprandial behavior, (2) an increase in the preprandial behavior directed toward the site of expected food, and (3) an increase in the postprandial distribution of both site-directed and more general exploratory behavior. These findings suggest that adjunctive behavior is not extraneous, but is an orderly distribution of responses ordinarily related to feeding and foraging for food.     

Text density level as a design variable in instructional displays

Presenting narrative text in computer-based instruction (CBI) is more difficult than in print lessons due to limited screen resolution and display area. The present research aimed at achieving a more compatible match between lesson content and the attributes of the presentation media. Subjects received either a print or CBI statistics lesson containing low-density (concise) narrative text, high-density (conventional) text, or the density type they preferred (learner-control). Results showed the low-density lesson to reduce completion time relative to the high-density version, while yielding equivalent achievement. Subjects receiving the lesson in the print mode had shorter completion times and higher achievement than their CBI counterparts. Attitude results showed that CBI was favorably regarded, but perceived as longer and slow-moving than print. Implications of results for designing instructional material in accord with CBI attributes and learner characteristics are discussed.     

Technology-enhanced Courses and a Mode III Organization of Instructional Work

Although information technology is increasingly used to deliver distance and conventional courses, there have been few studies of the effect of technology-enhanced education on the organization and purposes of academics’ instructional work. I explore this issue in undergraduate and masters level education through the vehicle of case analyses of technology-rich classes taught in a public research university in the United States. What the cases illustrate is an emergent pattern of what I am calling ‘Mode III’ instructional production, in which the production of a course involves a matrix of non-faculty support personnel, and may be oriented to commercial purposes reflective of an increasingly embedded academic capitalism in the new economy.

     

Longitudinal factor structure of the WISC‐III among students with disabilities

If the factor structure of a test does not hold over time (i.e., is not invariant), then longitudinal comparisons of standing on the test are not meaningful. In the case of the Wechsler Intelligence Scale for Children‐Third Edition (WISC‐III), it is crucial that it exhibit longitudinal factorial invariance because it is widely used in high‐stakes special education eligibility decisions. Accordingly, the present study analyzed the longitudinal factor structure of the WISC‐III for both configural and metric invariance with a group of 177 students with disabilities tested, on average, 2.8 years apart. Equivalent factor loadings, factor variances, and factor covariances across the retest interval provided evidence of configural and metric invariance. It was concluded that the WISC‐III was measuring the same constructs with equal fidelity across time which allows unequivocal interpretation of score differences as reflecting changes in underlying latent constructs rather than variations in the measurement operation itself. © 2001 John Wiley & Sons, Inc.     

Educational expenditures and student engagement: When does money matter?

The few studies focusing on the relationships between higher education expenditures and student outcomes have produced contradictory results. This study hypothesized that the lack of consistent relationships is a function of the fact that the effects of expenditures on outcomes are mediated by student engagement. Furthermore, it is expected that the relationships between expenditures and outcomes are contingent on the characteristics of the students and institutions being studied. The present research examined the relationships between higher education expenditures and students’ engagement in educationally purposeful activities, after controlling for a variety of student and institutional characteristics. Using data from a nationally representative sample of colleges and universities, the findings indicated that the relationships between expenditures and student engagement are very complex. Relationships differed by institutional control, students’ year in school, and the type of engagement measure included in the analysis.     

Using structural equation models with latent variables to study student growth and development

Calls for accountability, coupled with a desire to improve teaching and learning, have prompted many colleges and universities to consider ways of assessing the effects of postsecondary education on student growth and development. Despite widespread support for the concept of assessing student change, relatively few institutions have implemented this type of assessment, in part because of a concern about the best method of measuring change. This article describes the use of structural equation models with latent variables to assess the effects of education on change. Advantages of using structural equation models with latent variables include error-free measurement of change, direct tests of the assumptions underlying change research, along with the power and flexibility of maximum likelihood estimation. An analysis of data on freshman-to-senior gains provides evidence of the advantages of latent variable structural equation modeling and also suggests that the group differences identified by traditional analysis of variance and covariance techniques may be an artifact of measurement error.