Visualizing the dynamics of soil aggregation as affected by arbuscular mycorrhizal fungi.

Stable soils provide valuable ecosystem services and mechanical soil stability is enhanced by the presence of arbuscular mycorrhizal fungi (AMF). Soil aggregation, which is the major driver of mechanical soil stability, is often treated as a static phenomenon, even though aggregate turnover is continually ongoing. In fact, some breakdown of macroaggregates is necessary to allow new aggregate formation and inclusion of new organic matter into microaggregates. We determined how aggregate turnover times were affected by AMF by tracking movement of rare earth elements (REE), applied as their immobile oxides, between aggregate size classes, and using X-ray fluorescence microscopy to spatially localize REEs in a sample of aggregates. Here we show that AMF increased large macroaggregate formation and slowed down disintegration of large and small macroaggregates. Microaggregate turnover was increased in the presence of AMF. Internal aggregate organization suggested that although formation of microaggregates by accretion of soil to particulate organic matter is common, it is not the only mechanism in operation.

Some reflections on 25 years of the association for behavior analysis: Past, present, and future.

This paper offers some reflections on the discipline and profession of behavior analysis, as well as on the Association for Behavior Analysis (ABA), on the occasion of the association's 25th anniversary. It is based on a panel session conducted at the 1999 convention that included six past presidents of ABA (Donald M. Baer, Judith E. Favell, Sigrid S. Glenn, Philip N. Hineline, Jack Michael, and Edward K. Morris) and its current Executive Director and Secretary-Treasurer (Maria E. Malott). Among the topics addressed were (a) the survival of behavior analysis in university and cultural contexts, (b) the training of behavior-analytic researchers and practitioners, (c) relations between basic and applied research, (d) convergences between behavior analysis and other disciplines, (e) the structure and function of ABA, and (f) the importance of students for the future of the association, the discipline, and the profession. Questions from the audience raised issues concerning the relevance of major behavior-analytic journals, advances in behavior analysis since the death of B. F. Skinner, and the availability of accessible, popular material on applied behavior analysis.

The premack principle, response deprivation, and establishing operations.

This paper describes response deprivation as an establishing operation. In this context, we review the concept of establishing operation, in particular, its reinforcer-establishing and evocative effects; we place response deprivation in the literature on the reinforcing effects of behavioral activity, wherein response deprivation subsumes the Premack principle; we describe the reinforcer-altering and evocative effects of response deprivation; and we address a methodological concern about the evocative effect. In closing, we discuss some conceptual and empirical implications of the foregoing analyses.

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.

Behavior analysis and mechanism: One is not the other.

Behavior analysts have been called mechanists, and behavior analysis is said to be mechanistic; that is, they are claimed to be aligned with the philosophy of mechanism. What this means is analyzed by (a) examining standard and specialized dictionary and encyclopedia definitions and descriptions of mechanism and its cognates and (b) reviewing contemporary representations of the mechanistic worldview in the literature on the philosophy of psychology. Although the term mechanism and its cognates are sometimes an honorific (e.g., "natural science"), their standard meanings, usages, and functions in society, science, psychology, and philosophy do not aptly characterize the discipline. These terms mischaracterize how behavior analysts conceptualize (a) the behavior of their subjects and the individuals with whom they work and (b) their own behavior as scientists. Discussion is interwoven throughout about the nature of terms and definitions in science.

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.

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.

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.

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.

The history of behavior analysis: Some historiography and a bibliography.

This article has two main purposes. First, it introduces the discipline of historiography and, second, it provides a selected bibliography on the history of behavior analysis. In introducing the former in the context of the latter, four important methodological considerations involved in the process and product of historiography are described: The sources from which historical materials are drawn (i.e., primary, secondary, and tertiary) and three dimensions along which historiography is conducted and evaluated-internalist vs. externalist, great person vs. Zeitgeist, and presentist vs. historicist. Integrated throughout are four purposes for the historiography of behavior analysis, as well as an overview of the topics covered in the extant literature. The manuscript concludes with a listing of current bibliographic material by publication type and topic.

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.

Behavior analysis and public policy.

The Task Force on Public Policy was created to examine ways for behavior analysts to be more functional citizen scientists in the policymaking arena. This report informs readers about the contexts and processes of policymaking; and it outlines issues regarding the roles of behavior analysts in crating policy-relevant conceptual analyses, generating research data, and communicating policy-relevant information. We also discuss a possible role for the professional association in enhancing analysis, research, and advocacy on policies relevant to the public interest.

A history of the term radical behaviorism: From Watson to Skinner.

This paper describes the origins and evolution of the term radical behaviorism. John B. Watson's coining of behaviorism in 1913 is presented first, followed by a discussion of the uses of "radical" within psychology during these early years. When the term radical behaviorism first emerged in the early 1920s, its referent was Watson's behaviorism, most specifically his stance on consciousness. In the 1930s, B. F. Skinner described his own position with the term radical behaviorism in an unpublished manuscript, and then in 1945 first referred in print to his views as such. Today, radical behaviorism is generally applied to Skinner's views alone. The paper concludes with a brief discussion of a similarity in Watson's and Skinner's positions on consciousness, which seems a possible historical and philosophical connection between their respective radical behaviorisms.