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Biomedical subjects

E K Morris

Publications and source records attributed to E K Morris.

10 recordsLinked to original sources
PubMed1997

The generation and maintenance of schedule-induced polydipsia in normal male rats without weight reduction.

Experiment One demonstrated that two normal male Sprague-Dawley rats (approximately 60 days old) with free access to food and two control rats whose weights were held constant by dietary restriction acquired schedule-induced polydipsia (SIP) in daily 33-35 min sessions of fixed-time 60-s food delivery. Three of the rats showed rapid acquisition of SIP; the fourth acquired SIP more slowly and consumed less per session the other three rats. After a 36-40 day period without sessions, the constant-weight rats showed a 37% decrease in overall consumption due to reduced drinking bout length. The SIP of the free-feeding rats was not affected by the interruption. After 90-100 periodic food delivery sessions, all subjects consumed an average of 11.2-12.2 mL per session compared with 1.8-4.8 mL per session in baseline sessions with massed food presentations. Experiment Two replicated the acquisition phase of Experiment One using two non-weight-reduced rats of the age and size of those typically used in SIP studies (approximately 30 weeks old). Both acquired SIP, although one showed only a small average increase in consumption per session over baseline (2.8 mL/session under periodic food vs. 0.8 mL following massed-food presentations). Before weight reduction, the stronger drinker consumed approximately 8.8 mL per session compared with an average of 0.6 mL per session in baseline. After weight reduction, both exhibited strong SIP (18-19 mL per session in the final five sessions). This study demonstrates that weight reduction is not a necessary condition for the generation and maintenance of SIP in rats.

Animals↗
PubMed1992

Case histories in the great power of steady misrepresentation.

The widespread misrepresentation of behaviorism in the scientific and popular literature has caused its contributions to the understanding of behavior to be systematically ignored or denied. This misrepresentation is manifested, in large part, as a form of academic folklore that codifies erroneous accounts of behaviorism's assumptions, findings, and goals. This article examines three representative "case histories" of the academic folklore about behaviorism: its alleged environmentalism, totalitarian aims, and intellectual intolerance. Because academic folklore has been highly resistant to the corrective efforts of behaviorists, explicit strategies are suggested for identifying and correcting folklore and for promoting more effective interdisciplinary communication.

Behaviorism↗
PubMed1992

Sequences of spaced responses: Behavioral units and the role of contiguity.

Sequences of temporally spaced responses were reinforced to investigate the effects of delay of reinforcement on the formation of functional behavioral units. In Experiment 1, rats' two- and three-response demarcated sequences of left and right lever presses were reinforced such that different response distributions would occur depending on whether the sequences themselves or individual responses were functional units. The matching law could thus be obeyed either by individual responses or by sequences, but not by both; intermediate results were possible. Both regular (nonretractable) and retractable levers were used; the retractable levers precluded the occurrence of insufficiently spaced responses. At a minimum interresponse time of 5 s for regular levers and 7 s for retractable ones, matching results were intermediate, with greater evidence of sequence conditionability in the two-response sequences than in the three-response sequences. In Experiment 2, the required minimum interresponse spacing for two-response retractable-lever sequences was varied in an attempt to locate the sequence matching threshold. This attempt was unsuccessful, but the sequences (instead of individual responses) more closely obeyed the matching law. In the shortest spaced condition, conditional probability data on Lag 1 sequence emission order showed marked, highly similar patterning for all rats, indicating sequential control of the sequences. Post hoc definition of the behavioral unit in these studies is ambiguous. Although reinforcement contiguity was important, aspects of the results could support both molar- and molecular-level interpretations.

Journal Article↗
PubMed1991

Cost per case comparison of back injury claims of chiropractic versus medical management for conditions with identical diagnostic codes.

This study assessed the total cost per case of chiropractic claims and medical claims for conditions with identical diagnostic codes. The sample consisted of 3062 claims or 40.6% of the 7551 estimated back injury claims from the 1986 Workers' Compensation Fund of Utah. For the total data set, cost for care was significantly more for medical claims, and compensation costs were 10-fold less for chiropractic claims.

Adult↗
PubMed1991

The effects of schedule history and the opportunity for adjunctive responding on behavior during a fixed-interval schedule of reinforcement.

The effects of schedule history and the availability of an adjunctive response (polydipsia) on fixed-interval schedule performance were investigated. Two rats first pressed levers under a schedule of food reinforcement with an interresponse time greater than 11 s, and 2 others responded under a fixed-ratio 40 schedule. All 4 were then exposed to a fixed-interval 15-s schedule. Water was continuously available under these conditions, but after responding became stable on the fixed-interval schedule, access was experimentally manipulated. With water freely available, subjects did not display characteristic fixed-interval response rates and patterns (i.e., scalloping or break-and-run). Instead, they exhibited predictable, stable patterns of behavior as a function of their schedule histories: Subjects with the interresponse-time history exhibited low response rates, and those with the fixed-ratio history exhibited high rates. Manipulating the amount of water available resulted in marked changes in response rates for rats with the interresponse-time history but not for those with the fixed-ratio history. The results illustrate the multiple causation of behavior by its previous and current schedules of reinforcement and other concurrent factors.

Animals↗
PubMed1988

Teachers' instructions and children's compliance in preschool classrooms: a descriptive analysis.

This study presents a methodology for collecting detailed naturalistic data on preschool teachers' instructions and children's compliance and a descriptive analysis of variables related to instruction rate and compliance probability. In preschools, teachers and children were observed across a variety of classroom activities. Kindergarten and first-grade teachers also were observed to permit a comparison of instructional behavior between preschool and early elementary settings. Among teachers, instructions varied in frequency but displayed consistencies in form. For example, teachers more often phrased instructions as imperatives than as questions or declaratives and directed more instructions to individuals than to groups. Teachers' instructional behavior varied across preschool activities and between preschool and elementary grades. Children's compliance was related to the context of an instruction, but not to its form. In addition to providing information about naturally occurring instructional events, the results illustrate the effects of context on teacher and child behavior and suggest directions for future descriptive and experimental research.

Child↗