bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFECTS OF EXPERIENCE ON PREFERENCE BETWEEN FORCED AND FREE CHOICE
Authors: Ono Koichi
Published: March 2006

Preference between forced choice and free choice in concurrent‐chain schedules of reinforcement was investigated in pigeons after exposure to particular combinations of terminal links. In Experiment 1, in which terminal links always ended with reinforcers, one of three pairs of terminal links was arranged as preexposure: (a) both terminal links had only one key (forced choice), (b) both terminal links had two keys (free choice), or (c) a combination of forced and free choice was arranged across sessions. In test sessions following the preexposure, pigeons' preferences rapidly shifted to the terminal links with which they had no recent experience. In Experiment 2, the same procedure was repeated except that each terminal link ended intermittently with reinforcers with a probability of .5 and there was no terminal‐link arrangement with a combination of free and forced choice. Pigeons showed the same preference changes as in Experiment 1, but the preference changes did not appear immediately at the beginning of test sessions. These data suggest that recent previous experience was a more important determinant of preference than the difference between forced‐choice and free‐choice terminal links.
A COMPUTATIONAL MODEL OF SELECTION BY CONSEQUENCES
Authors: McDowell J. J.
Published: March 2006

Darwinian selection by consequences was instantiated in a computational model that consisted of a repertoire of behaviors undergoing selection, reproduction, and mutation over many generations. The model in effect created a digital organism that emitted behavior continuously. The behavior of this digital organism was studied in three series of computational experiments that arranged reinforcement according to random‐interval (RI) schedules. The quantitative features of the model were varied over wide ranges in these experiments, and many of the qualitative features of the model also were varied. The digital organism consistently showed a hyperbolic relation between response and reinforcement rates, and this hyperbolic description of the data was consistently better than the description provided by other, similar, function forms. In addition, the parameters of the hyperbola varied systematically with the quantitative, and some of the qualitative, properties of the model in ways that were consistent with findings from biological organisms. These results suggest that the material events responsible for an organism's responding on RI schedules are computationally equivalent to Darwinian selection by consequences. They also suggest that the computational model developed here is worth pursuing further as a possible dynamic account of behavior.
UNIT PRICE AND CHOICE IN A TOKEN‐REINFORCEMENT CONTEXT
Authors: Foster Theresa A. , Hackenberg Timothy D.
Published: March 2006

Pigeons were exposed to multiple and concurrent second‐order schedules of token reinforcement, with stimulus lights serving as token reinforcers. Tokens were produced and exchanged for food according to various fixed‐ratio schedules, yielding equal and unequal unit prices (responses per unit food delivery). On one schedule (termed the standard schedule), the unit price was held constant across conditions. On a second schedule (the alternative schedule), the unit price was either the same or different from the standard. Under conditions with unequal unit prices, near‐exclusive preference for the lower unit price was obtained. Under conditions with equal unit prices, the direction and degree of preference depended on ratio size (number of responses per exchange period). When this ratio differed, strong preferences for the smaller ratio were observed. When this ratio was equal, preferences were nearer indifference. Response rates on the multiple schedule were generally consistent with the preference data in showing sensitivity to ratio size. Results are discussed in terms of a unit‐price model that includes handling and reinforcer immediacy as additional costs. On the whole, results show that preferences were determined primarily by delay to the exchange period.
TRANSFER TO INTERMEDIATE FORMS FOLLOWING CONCEPT DISCRIMINATION BY PIGEONS: CHIMERAS AND MORPHS
Authors: Ghosh Natasha , Lea Stephen E. G. , Noury Malia
Published: March 2006

Two experiments examined pigeons' generalization to intermediate forms following training of concept discriminations. In Experiment 1, the training stimuli were sets of images of dogs and cats, and the transfer stimuli were head/body chimeras, which humans tend to categorize more readily in terms of the head part rather than the body part. In Experiment 2, the training stimuli were sets of images of heads of dogs and cats, and the intermediate stimuli were computer‐generated morphs. In both experiments, pigeons learned the concept discrimination quickly and generalized with some decrement to novel instances of the categories. In both experiments, transfer tests were carried out with intermediate forms generated from both familiar and novel exemplars of the training sets. In Experiment 1, the pigeons' transfer performance, unlike that of human infants exposed to similar stimuli, was best predicted by the body part of the stimulus when the chimeras were formed from familiar exemplars. Spatial frequency analysis of the stimuli showed that the body parts were richer in high spatial frequencies than the head parts, so these data are consistent with the hypothesis that categorization is more dependent on local stimulus features in pigeons than in humans. There was no corresponding trend when the chimeras were formed from novel exemplars. In Experiment 2, when morphs of training stimuli were used, response rates declined smoothly as the proportion of the morph contributed by the positive stimulus fell, although results with morphs of novel stimuli were again less orderly.
MATCHING: ITS ACQUISITION AND GENERALIZATION
Authors: Crowley Michael A. , Donahoe John W.
Published: March 2006

Choice typically is studied by exposing organisms to concurrent variable‐interval schedules in which not only responses controlled by stimuli on the key are acquired but also switching responses and likely other operants as well. In the present research, discriminated key‐pecking responses in pigeons were first acquired using a multiple schedule that minimized the reinforcement of switching operants. Then, choice was assessed during concurrent‐probe periods in which pairs of discriminative stimuli were presented concurrently. Upon initial exposure to concurrently presented stimuli, choice approximated exclusive preference for the alternative associated with the higher reinforcement frequency. Concurrent schedules were then implemented that gave increasingly greater opportunities for switching operants to be conditioned. As these operants were acquired, the relation of relative response frequency to relative reinforcement frequency converged toward a matching relation. An account of matching with concurrent schedules is proposed in which responding exclusively to the discriminative stimulus associated with the higher reinforcement frequency declines as the concurrent stimuli become more similar and other operants—notably switching—are acquired and generalize to stimuli from both alternatives. The concerted effect of these processes fosters an approximate matching relation in commonly used concurrent procedures.
THE TRANSFORMATION OF CONSEQUENTIAL FUNCTIONS IN ACCORDANCE WITH THE RELATIONAL FRAMES OF SAME AND OPPOSITE
Authors: Whelan Robert , Barnes‐Holmes Dermot
Published: March 2006

Although the literature on reinforcement in behavioral psychology is extensive, few studies have examined the derived transformation of reinforcing functions in accordance with equivalence classes, and no published research has yet examined the derived transformation of consequential functions in accordance with nonequivalence relations. In the present study, which consisted of four experiments, the basic preparation was as follows. First, an arbitrary stimulus, B2, was established as a conditioned punisher, using direct stimulus pairing. Following nonarbitrary relational training, designed to establish SAME and OPPOSITE contextual cues, subjects were exposed to arbitrary relational training using these contextual cues to establish A1 as the same as B1 and C1, and as opposite to B2 and C2. Subsequently, C2 (based on its Same relation with B2) functioned as a punisher and C1 (based on its Opposite relation with B2) functioned as a reinforcer in a simultaneous discrimination task. Critically, the C1 stimulus acquired reinforcing functions, based on the derived relation of Opposite, although no such function had actually been established for any member of the network. Furthermore, these effects were observed across ABA reversals in the baseline contingencies.
WITHIN‐SESSION DELAY‐OF‐REINFORCEMENT GRADIENTS
Authors: Reilly Mark P. , Lattal Kennon A.
Published: March 2006

Within‐session delay‐of‐reinforcement gradients were generated with pigeons by progressively increasing delays to reinforcement within each session. In Experiment 1, the effects of imposing progressive delays on variable‐interval and fixed‐interval schedules were investigated while controlling for simultaneous decreases in reinforcer rate across the session via a within‐subject yoked‐control procedure. Rate of key pecking decreased as a negatively decelerated function of delay of reinforcement within a session. These rate decreases were greater than those during a yoked‐interval session in which the rate of immediate reinforcement decreased at the same rate as it did under the progressive‐delay procedure. In Experiment 2, delay‐of‐reinforcement gradients were shallower when the progressive delay intervals were signaled by a blackout than when they were unsignaled. The delay gradients obtained in each experiment were similar to those generated under conditions in which different delays of reinforcement are imposed across blocks of sessions. The present procedure offers a technique for rapidly generating delay‐of‐reinforcement gradients that might serve as baselines for assessing the effects of other behavioral and pharmacological variables.
RELATIONAL OPERANTS: PROCESSES AND IMPLICATIONS: A RESPONSE TO PALMER'S REVIEW OF RELATIONAL FRAME THEORY
Authors: Hayes Steven C. , Barnes‐Holmes Dermot
Published: March 2006

Palmer has recently criticized Relational Frame Theory (RFT) on the grounds that it has developed data in search of a principle. In this reply, we show that he has done so by attacking fundamental concepts within behavior analysis itself, including the functional nature of an operant and contingencies of reinforcement as a behavioral process. His claim that RFT appeals to new behavioral principles to explain the development of relational operants is shown to be incorrect: As with any operant, RFT appeals to a history of contacted consistencies in contingencies across multiple exemplars to explain them. New principles only emerge later as a logically necessary extension of such operants if they exist—a view that Palmer failed to address or appreciate. Palmer's desire to see the use of methods other than matching‐to‐sample is proper but already largely satisfied in the empirical literature on RFT. We show Palmer's defense of Skinner's definition of verbal behavior to be illogical and unresponsive to the empirical challenge behavior analysis faces. Palmer's alternative common sense mediational associationistic account is another in more than a century of such accounts, all of which have failed empirically. At its root, Palmer's criticism is based on a mechanistic philosophy that is hostile to a traditional functional behavior analytic approach.
GENERIC RESPONSE CLASSES AND RELATIONAL FRAME THEORY: RESPONSE TO HAYES AND BARNES‐HOLMES
Authors: Palmer David C.
Published: March 2006

Hayes and Barnes‐Holmes (2004) assert that the concept of a topographically unconstrained response class, the concept that carries the explanatory burden of relational frame theory, appeals to no new principles. Operants are properly defined functionally. I argue that they have stretched the concept of the generic response class beyond its appropriate limits. Skinner conceived of response classes as empirically defined units, mutually interchangeable in quantitative functions. The notion of overarching, generalized operants is an uncritical, analogical extension of this concept. I hold that the conceptual work of relational frame theory is incomplete, that a statement of principle is necessary, even if not new. Finally, I distinguish a supposed commitment to a philosophical “mediationism” from a valid inquiry about mediating behavior; that is, behavior with stimulus products that participate in the control of the behavior of primary interest.
INDEPENDENCE OF TERMINAL‐LINK ENTRY RATE AND IMMEDIACY IN CONCURRENT CHAINS
Authors: Berg Mark E. , Grace Randolph C.
Published: March 2006

In Phase 1, 4 pigeons were trained on a three‐component multiple concurrent‐chains procedure in which components differed only in terms of relative terminal‐link entry rate. The terminal links were variable‐interval schedules and were varied across four conditions to produce immediacy ratios of 4: 1, 1:4, 2:1, and 1:2. Relative terminal‐link entry rate and relative immediacy had additive and independent effects on initial‐link response allocation, and the data were well‐described by a generalized‐matching model. Regression analyses showed that allowing sensitivity to immediacy to vary across components produced only trivial increases in variance accounted for. Phase 2 used a three‐component concurrent‐schedules procedure in which the schedules were the same as the initial links of Phase 1. Across two conditions, the relative reinforcer magnitude was varied. Sensitivity to relative reinforcer rate was independent of relative magnitude, confirming results of prior studies. Sensitivity to relative reinforcer rate in Phase 2 did not vary systematically across subjects compared to sensitivity to relative entry rate in Phase 1, and regression analyses confirmed again that only small increases in variance accounted for were obtained when sensitivities were estimated independently compared with a single estimate for both phases. Overall, the data suggest that conditioned and primary reinforcers have functionally equivalent effects on choice and support the independence of relative terminal‐link entry rate and immediacy as determiners of response allocation. These results are consistent with current models for concurrent chains, including Grace's (1994) contextual choice model and Mazur's (2001) hyperbolic value‐added model.
TYPICALITY EFFECTS IN CONTINGENCY‐SHAPED GENERALIZED EQUIVALENCE CLASSES
Authors: Galizio Mark , Stewart Katherine L. , Pilgrim Carol
Published: March 2006

Two experiments were conducted using match‐to‐sample methodologies in an effort to model lexical classes, which include both arbitrary and perceptual relations between class members. Training in both experiments used a one‐to‐many mapping procedure with nonsense syllables as samples and eight sets of abstract stimuli as comparisons. These abstract stimuli differed along a number of dimensions, four of which were critical to the experimenter‐defined class membership. Stimuli in some comparison sets included only one of the class‐defining features, but stimuli in other sets included two, three, or all four of the critical features. After mastery of the baseline training, three types of probe tests were conducted: symmetry, transitivity/equivalence, and novel probe tests in which the training nonsense syllables served as samples, and comparisons were novel abstract stimuli that included one or more of the class‐defining features. Symmetry and transitivity/equivalence probe tests showed that the stimuli used in training became members of equivalence classes. The novel stimuli also became class members on the basis of inclusion of any of the critical features. Thus these probe tests revealed the formation of open‐ended generalized equivalence classes. In addition, typicality effects were observed such that comparison sets with more critical features were learned with fewer errors, responded to more rapidly, and judged to be better exemplars of the class. Contingency‐shaped stimulus classes established through a match‐to‐sample procedure thus show several important behavioral similarities to natural lexical categories.
EFFECTS OF ANORECTIC DRUGS ON FOOD INTAKE UNDER PROGRESSIVE‐RATIO AND FREE‐ACCESS CONDITIONS IN RATS
Authors: Le Sage Mark G. , Stafford David , Glowa John R.
Published: March 2006

The effects of two anorectic drugs, dexfenfluramine and phentermine, on food intake under different food‐access conditions were examined. Experiment 1 compared the effects of these drugs on food intake under a progressive‐ratio (PR) schedule and free‐access conditions. Dexfenfluramine decreased food intake under both conditions, but the doses required to decrease intake under free‐access conditions were higher than those required to reduce intake under the PR condition. Intermediate doses of phentermine sometimes increased breaking points, and higher doses decreased them. Phentermine decreased food intake at the same doses under both access conditions. Thus the potency of dexfenfluramine, but not phentermine, to decrease food‐maintained behavior depended upon the food‐access condition. Experiment 2 used a novel mixed progressive‐ratio schedule of food delivery to study the duration of drug effects. Sessions consisted of five components separated by 3‐hr timeouts. The ratio requirement reset at the beginning of each component and a new breaking point was obtained. Both dexfenfluramine and phentermine dose‐dependently decreased breaking points early in the session. In some rats, compensatory increases in breaking point were observed. That is, breaking points later in the session increased over control levels, resulting in no change in the total number of food pellets earned for the session compared to control. The present findings suggest that the effects of some anorectic drugs depend upon the access conditions for food; increasing the effort to obtain food may enhance their ability to decrease food‐maintained behavior.
EFFECTS OF COCAINE ON PERFORMANCE UNDER FIXED‐INTERVAL SCHEDULES WITH A SMALL TANDEM RATIO REQUIREMENT
Authors: Pinkston Jonathan W. , Branch Marc N.
Published: March 2006

Daily administration of cocaine often results in the development of tolerance to its effects on responding maintained by fixed‐ratio schedules. Such effects have been observed to be greater when the ratio value is small, whereas less or no tolerance has been observed at large ratio values. Similar schedule‐parameter‐dependent tolerance, however, has not been observed with fixed‐interval schedules arranging comparable interreinforcement intervals. This experiment examined the possibility that differences in rate and temporal patterning between the two types of schedule are responsible for the differences in observed patterns of tolerance. Five pigeons were trained to key peck on a three‐component multiple (tandem fixed‐interval fixed‐ratio) schedule. The interval values were 10, 30, and 120 s; the tandem ratio was held constant at five responses. Performance appeared more like that observed under fixed‐ratio schedules than fixed‐interval schedules. Effects of various doses of cocaine given weekly were then determined for each pigeon. A dose that reduced responding was administered prior to each session for 50 days. A reassessment of effects of the range of doses revealed tolerance. The degree of tolerance was similar across components of the multiple schedule. Next, the saline vehicle was administered prior to each session for 50 days to assess the persistence of tolerance. Tolerance diminished in all subjects. Overall, the results suggested that schedule‐parameter‐dependent tolerance does not depend on the temporal pattern of responding engendered by fixed‐ratio schedules.
THE ETYMOLOGY OF BASIC CONCEPTS IN THE EXPERIMENTAL ANALYSIS OF BEHAVIOR
Authors: Dinsmoor James A.
Published: March 2006

The origins of many of the basic concepts used in the experimental analysis of behavior can be traced to Pavlov's (1927/1960) discussion of unconditional and conditional reflexes in the dog, but often with substantial changes in meaning (e.g., stimulus, response, and reinforcement). Other terms were added by Skinner (1938/1991) to describe his data on the rate of lever pressing in the rat (e.g., operant conditioning, conditioned reinforcement, negative reinforcement, and response induction and differentiation) and key pecking in the pigeon (shaping). The concept of drive, however, has largely disappeared from the current literature.
STEPS AND PIPS IN THE HISTORY OF THE CUMULATIVE RECORDER
Authors: Lattal Kennon A.
Published: March 2006

From its inception in the 1930s until very recent times, the cumulative recorder was the most widely used measurement instrument in the experimental analysis of behavior. It was an essential instrument in the discovery and analysis of schedules of reinforcement, providing the first real‐time analysis of operant response rates and patterns. This review traces the evolution of the cumulative recorder from Skinner's early modified kymographs through various models developed by Skinner and his colleagues to its perfection in the 1950s, and then into the 1960s when it proliferated as different scientific instrument companies began marketing their own models of the cumulative recorder. With the rise of digital computers, the demise of the cumulative recorder as a scientific instrument was inevitable; however, the value of the cumulative record as a monitoring device to assess schedule control of behavior continues. The cumulative recorder remains, along with the operant conditioning chamber, an icon of Skinner's approach to psychology.
SIGNAL‐DETECTION ANALYSES OF CONDITIONAL DISCRIMINATION AND DELAYED MATCHING‐TO‐SAMPLE PERFORMANCE
Authors: Alsop Brent
Published: March 2006

Quantitative analyses of stimulus control and reinforcer control in conditional discriminations and delayed matching‐to‐sample procedures often encounter a problem; it is not clear how to analyze data when subjects have not made errors. The present article examines two common methods for overcoming this problem. Monte Carlo simulations of performance demonstrated that both methods introduced systematic deviations into the results, and that there were genuine risks of drawing misleading conclusions concerning behavioral models of signal detection and animal short‐term memory.
SHIPS THAT PASS IN THE NIGHT
Authors: Donahoe John W.
Published: March 2006

A major source of tension between Staddon's The new behaviorism and Baum's Review is that the former was written for a general audience but the latter evaluates it as a technical work. Be that as it may, the central issue—Skinner's conception of the role of theory in behavior analysis—is inadequately portrayed in both the book and the review. The two primary sources of difficulty arise from failures to honor Skinner's distinction between experimental analysis and interpretation and to appreciate Skinner's views on events that are not observable at the behavioral scale of measurement.
MODERN MOLAR BEHAVIORISM AND THEORETICAL BEHAVIORISM: RELIGION AND SCIENCE
Authors: Malone John C.
Published: March 2006

Baum and staddon disagree on the status of internal states in behavior analysis. Baum advocates molar behaviorism, treating behavior in temporally extended segments and so avoiding the need for internal states. Staddon argues that internal states merely represent the effects of different histories and that their use brings behavior analysis in line with the established sciences. The dispute is one form of the age‐old molar—molecular controversy that characterized Aristotle's disagreement with Plato. Both molar and molecular analyses have their place, but molar behaviorism may apply more naturally to a variety of phenomena, ranging from the matching law and avoidance learning to socalled “higher mental processes.” When molecular analysis involves internal states, as in Staddon's Theoretical Behaviorism (or New Behaviorism), misunderstanding will be inevitable and behaviorism will be seen as one more instance of the mediational theories in which psychology has long been mired. Such theories have long dominated the physical sciences, where their usefulness is indisputable, but psychology is far behind the physical sciences and nonmediational molar behaviorism better suits a discipline that lacks the methods and the data of the established sciences.
BEHAVIORISM MAKES ITS DEBUT: A REVIEW OF LATTAL AND CHASE'S BEHAVIOR THEORY AND PHILOSOPHY
Authors: Zuriff G. E.
Published: March 2006

Behavior Theory and Philosophy, masterfully edited by Lattal and Chase, is a collection of 21 papers by major behaviorists, presented and discussed at a conference on the intersection of philosophy and behavior analysis held at West Virginia University in 2000. The chapters in Part I are devoted to philosophy of science (causality, constructs, theory, explanation, reductionism) and the relations among behavior analysis and several contemporary philosophical movements (humanism, empiricism, pragmatism, selectionism, analytic philosophy). Part II examines behavior‐analytic interpretations of mentalistic concepts (intention, imagination, ethics, cognition). Part III presents extensions and applications of basic research in behavior analysis (verbal behavior, creativity, development, education, disability, and corporate culture). The publication of this book signals that behaviorism has developed mature philosophical foundations.
MORPHINE TOLERANCE AS A FUNCTION OF RATIO SCHEDULE: RESPONSE REQUIREMENT OR UNIT PRICE?
Authors: Hughes Christine E. , Sigmon Stacey C. , Pitts Raymond C. , Dykstra Linda A.
Published: March 2006

Key pecking by 3 pigeons was maintained by a multiple fixed‐ratio 10, fixed‐ratio 30, fixed‐ratio 90 schedule of food presentation. Components differed with respect to amount of reinforcement, such that the unit price was 10 responses per 1‐s access to food. Acute administration of morphine, l‐methadone, and cocaine dose‐dependently decreased overall response rates in each of the components. When a rate decreasing dose of morphine was administered daily, tolerance, as measured by an increase in the dose that reduced response rates to 50% of control (i.e., the ED50 value), developed in each of the components; however, the degree of tolerance was smallest in the fixed‐ratio 90 component (i.e., the ED50 value increased the least). When the l‐methadone dose‐effect curve was redetermined during the chronic morphine phase, the degree of cross‐tolerance conferred to l‐methadone was similar across components, suggesting that behavioral variables may not influence the degree of cross‐tolerance between opioids. During the chronic phase, the cocaine dose‐effect curve shifted to the right for 2 pigeons and to the left for 1 pigeon, which is consistent with predictions based on the lack of pharmacological similarity between morphine and cocaine. When the morphine, l‐methadone, and cocaine dose‐effect curves were redetermined after chronic morphine administration ended, the morphine and l‐methadone ED50s replicated those obtained prior to chronic morphine administration. The morphine data suggest that the fixed‐ratio value (i.e., the absolute output) determines the degree of tolerance and not the unit price.
EFFECTS OF REINFORCEMENT HISTORY ON RESPONSE RATE AND RESPONSE PATTERN IN PERIODIC REINFORCEMENT
Authors: López Florente , Menez Marina
Published: March 2006

Several researchers have suggested that conditioning history may have long‐term effects on fixed‐interval performances of rats. To test this idea and to identify possible factors involved in temporal control development, groups of rats initially were exposed to different reinforcement schedules: continuous, fixed‐time, and random‐interval. Afterwards, half of the rats in each group were studied on a fixed‐interval 30‐s schedule of reinforcement and the other half on a fixed‐interval 90‐s schedule of reinforcement. No evidence of long‐term effects attributable to conditioning history on either response output or response patterning was found; history effects were transitory. Different tendencies in trajectory across sessions were observed for measures of early and late responding within the interreinforcer interval, suggesting that temporal control is the result of two separate processes: one involved in response output and the other in time allocation of responding and not responding.
UNSIGNALED DELAY OF REINFORCEMENT, RELATIVE TIME, AND RESISTANCE CHANGE
Authors: Shahan Timothy A. , Lattal Kennon A.
Published: March 2006

Two experiments with pigeons examined the effects of unsignaled, nonresetting delays of reinforcement on responding maintained by different reinforcement rates. In Experiment 1, 3‐s unsignaled delays were introduced into each component of a multiple variable‐interval (VI) 15‐s VI 90‐s VI 540‐s schedule. When considered as a proportion of the preceding immediate reinforcement baseline, responding was decreased similarly for the three multiple‐schedule components in both the first six and last six sessions of exposure to the delay. In addition, the relation between response rates and reinforcement rates was altered such that both parameters of the single‐response version of the matching law (i.e., k and Re) were decreased. Experiment 2 examined the effects of unsignaled delays ranging from 0.5 s to 8.0 s on responding maintained by a multiple VI 20‐s VI 120‐s schedule of reinforcement. Response rates in both components increased with brief unsignaled delays and decreased with longer delays. As in Experiment 1, response rates as a proportion of baseline were affected similarly for the two components in both the first six and last six sessions of exposure to the delay. Unlike delays imposed between two stimulus events, the effects of delays between responses and reinforcers do not appear to be attenuated when the average time between reinforcers is longer. In addition, the disruptions produced by unsignaled delays appear to be inconsistent with the general finding that responding maintained by higher rates of reinforcement is less resistant to change.
Management of the Patient Who Smokes and the Diabetic Patient in the Dental Office
Authors: Kunzel Carol , Lalla Evanthia , Lamster Ira B.
Published: March 2006

Background: Approaches to patient care consistent with a greater emphasis on the importance of risk factors associated with periodontal disease should include measures to reduce risk. In this article, we investigate the extent to which periodontists' and general practice dentists' (GPs) behaviors and attitudes reflect current understanding of the most important environmental risk factor for periodontitis (smoking) and the most important systemic disease risk factor for periodontitis (diabetes mellitus).

Methods: A mail survey of active periodontists and GPs in the Northeastern United States was conducted during the fall of 2002. Random samples of periodontists and GPs listed in the designated Northeastern states were drawn from the 2002 American Academy of Periodontology Directory and the 2001 American Dental Directory, respectively. Responses were received from 103 periodontists (for a response rate of 73%) and from 105 GPs (for a response rate of 80%).

Results: Although periodontists generally perform risk identification and management behaviors for patients who smoke or who have diabetes more frequently than GPs, both groups tend to engage in activities that inquire, discuss, and inform more than they tend to undertake measures to control or manage these risk factors. Rates of proactive patient management activities are quite low in both clinician groups.

Conclusions: There is a need to increase periodontists' and GPs' involvement in the active management of the patient who smokes and in the diabetic patient. Such actions can be expected to result in improved periodontal and general health outcomes.
Inhibition of Experimental Gingivitis in Beagle Dogs With Topical Mercaptoalkylguanidines
Authors: Paquette David W. , Rosenberg Adam , Lohinai Zsolt , Southan Garry J. , Williams Ray C. , Offenbacher Steven , Szabó Csaba
Published: March 2006

Background: Nitric oxide is a free radical produced in host tissues by constitutive and inducible forms of the enzyme nitric oxide synthase. Nitric oxide plays physiological roles, but it is also involved in the pathophysiology of several inflammatory conditions, including arthritis, ulcerative colitis, and circulatory shock. Local increases in inducible nitric oxide synthase (iNOS) and reactive nitrogen products have also been demonstrated in humans and animals with periodontal disease. This masked, randomized, placebo‐controlled preclinical investigation examined the effect of two mercaptoalkylguanidines, mercaptoethylguanidine (MEG) and guanidinoethyldisulfide (GED), which are iNOS inhibitors and reactive nitrogen scavenging compounds, on the development of experimental gingivitis in beagle dogs.

Methods: Fifteen female, 1‐year‐old beagles first completed a 2‐week dose‐escalation experiment during which a maximum tolerated dose was determined for MEG and GED gels. Thereafter, all animals were brought to optimal gingival health by mechanical scaling, followed by rigorous daily toothbrushing over a 4‐week washout period. Experimental gingivitis was then induced, with cessation of plaque control and institution of a soft diet over 8 weeks. Beagles randomly received 0.3% MEG, 0.3% GED, or placebo (vehicle) gels, topically applied twice daily to premolar teeth. Gingival inflammation, bleeding tendency, and supragingival plaque were clinically measured at baseline and at 2, 3, 4, 6, and 8 weeks. Comparisons among groups and between group pairs (active versus placebo) were made using Kruskal‐Wallis tests.

Results: From baseline to day 7, all groups expressed similar indices. Thereafter, significant and time‐dependent increases in the plaque index (PI), gingival index (GI), and percentage of bleeding on probing (%BOP) were observed in placebo‐treated beagles. Mean GI scores for beagles treated with GED or MEG gels remained at or below baseline levels for the entire treatment period. At weeks 2, 3, 4, and 8, GI scores were significantly lower for MEG and GED groups compared to the placebo group (P <0.05). In addition, MEG and GED gels significantly reduced gingival bleeding responses by 8 weeks (P <0.05). Although placebo‐treated beagles demonstrated %BOP scores of 43% at week 8, GED‐ and MEG‐treated beagles exhibited %BOP scores of 21% and 26%, respectively. Since no statistical difference among PI scores was noted for any of the time points, neither mercaptoalkylguanidine appeared to affect supragingival plaque levels.

Conclusion: The data from this preclinical study indicate that mercaptoalkylguanidines, topically administered, may significantly reduce experimental gingivitis in the beagle dog.
No Association Between Selected Candidate Gene Polymorphisms and Severe Chronic Periodontitis
Authors: Wohlfahrt Johan C. , Wu Tianxia , Hodges James S. , Hinrichs James E. , Michalowicz Bryan S.
Published: March 2006

Background: Chronic periodontitis (CP) risk is influenced by environmental and genetic factors. Using a case‐control design, we tested for associations between CP and selected DNA sequence variations (single nucleotide polymorphisms [SNPs]) in or near genes coding for proteins that play a role in the pathogenesis of this disease.

Methods: DNA was analyzed from 219 whites who were examined clinically. Cases (N = 137) were ≥35 years of age with eight or more teeth having ≥5 mm of proximal clinical attachment loss. Controls (N = 82) were ≥45 years of age with minimal or no proximal attachment loss or pocketing. Nine diallelic polymorphisms (gene and SNP descriptor) were studied in subjects: cytotoxic T‐lymphocyte antigen‐4 (CTLA‐4, 49 A>G), human β‐defensin‐1 (DEFB1, 692 G>A), intercellular adhesion molecule‐1 (ICAM‐1, 1548 A>G), Fas ligand (fasL, −844 C>T), inducible costimulator (ICOS, 3990 G>T), interleukin‐6 (IL‐6, −174 G>C), cysteine‐cysteine chemokine receptor‐5 (CCR5, 59653 C>T), osteoprotegerin (OPG, 245 T>G), and osteopontin (OPN, 707 C>T). Genotypes were determined using an automated fluorogenic 5′‐nuclease, polymerase chain reaction‐based assay. Gender and smoking history (pack‐years) were included as covariates in logistic regression analyses.

Results: Heavy smoking (>10 pack‐years) and male gender were significantly associated with disease (P <0.001). For all SNPs tested, the allele frequencies and distributions of genotypes did not differ between cases and controls (P >0.05). No unadjusted or adjusted odds ratios (comparing genotypes in cases versus controls) were significantly different than 1.0 (P >0.05) under any additive, dominant, or recessive inheritance model.

Conclusions: None of the SNPs tested were strongly associated with generalized severe chronic periodontitis in North American whites. A potentially more fruitful approach in future studies will be to test for associations between periodontitis and haplotype blocks constructed from either multiple SNPs in candidate gene regions or from panels of markers that span the entire genome.
The Extent of Alveolar Bone Loss Is Associated With Impaired Glucose Tolerance in Japanese Men
Authors: Saito T. , Murakami M. , Shimazaki Y. , Matsumoto S. , Yamashita Y.
Published: March 2006

Background: The treatment of periodontal disease in diabetic patients is reported to have a beneficial effect on their glucose control. A recent study indicated that having deep pockets is significantly associated with past development of glucose intolerance in non‐diabetic individuals using an oral glucose tolerance test (OGTT). These findings suggest that periodontal disease is a risk factor for diabetes, although more evidence is needed.

Methods: A total of 193 Japanese men aged 50 to 54 years with at least 10 teeth were examined as part of a comprehensive health examination before retirement from the Japan Self‐Defense Force. Alveolar bone loss of the posterior teeth was measured on a panoramic x‐ray film. An OGTT was administered and impaired glucose tolerance (IGT) and diabetes were defined. The relationships between the mean ratio of alveolar bone loss to root length and OGTT results were analyzed after adjusting for known risk factors for diabetes.

Results: The proportion of subjects with IGT increased significantly in the subjects with higher tertiles of alveolar bone loss (P <0.05). In the multivariate logistic regression analysis excluding diabetic subjects, the adjusted OR for IGT to normal glucose tolerance (NGT) increased in subjects with higher tertiles of alveolar bone loss (P for trend = 0.03). In the subjects with the highest tertile of alveolar bone loss, the adjusted OR for IGT to NGT was 4.27 (95% confidence interval [CI]: 1.41 to 12.9; P = 0.01).

Conclusion: The degree of alveolar bone loss is significantly associated with IGT, suggesting that periodontitis with alveolar bone loss is associated with impaired glucose tolerance.
Treatment of Class III Furcation Defects With Expanded Polytetrafluoroethylene Membrane Associated or Not With Anorganic Bone Matrix/Synthetic Cell‐Binding Peptide: A Histologic and Histomorphometric Study in Dogs
Authors: Roriz Virgílio M. , Souza Sérgio L.S. , Taba Mário , Palioto Daniela B. , Grisi Márcio F.M.
Published: March 2006

Background: Up until now, no predictable periodontal regeneration of Class III furcation defects has been demonstrated after treatment with different available techniques. Recently, a bone graft enriched with a peptide was developed and has shown satisfactory results when applied in intrabony defects. The aim of this study was to compare the use of expanded polytetrafluoroethylene (ePTFE) membrane associated (test group) or not (control group) with anorganic bovine‐derived bone matrix (ABM)/synthetic peptide, in the treatment of Class III furcation defects in dogs.

Methods: Six mongrel dogs were used in this study, and the second and fourth mandibular lower premolars were extracted. Class III furcation defects were surgically created in the third premolars and filled with impression material. Afterwards, the defects were surgically assessed for debridement and root planing. Teeth were randomly assigned into test and control groups. The membranes were removed after 4 weeks, and the animals were sacrificed 12 weeks later.

Results: Comparisons between groups by the Wilcoxon signed rank test showed no statistically significant differences in the parameters evaluated. In the control group, a new bone area (NBA) of 41.71% ± 24.07%, connective tissue area (CTA) of 36.34% ± 15.50%, and epithelium tissue area (ETA) of 9.39% ± 5.85% were observed. The new cementum extension (NCE) was 24.16% ± 13.18%. The test group presented an NBA of 31.84% ± 12.58%, CTA of 47.72% ± 11.33%, ETA of 9.17% ± 6.81%, and an NCE of 30.13% ± 16.43%.

Conclusion: There was no statistically significant difference between the two therapies: ePTFE membrane associated with ABM/synthetic peptide flow or ePTFE membrane only.
Periodontal Status in Patients With Gingival Mucous Membrane Pemphigoid
Authors: Tricamo Melissa B. , Rees Terry D. , Hallmon William W. , Wright John M. , Cueva Marco A. , Plemons Jacqueline M.
Published: March 2006

Background: Mucous membrane pemphigoid (MMP) describes an autoimmune disease with a range of variants, including those with oral, ocular, and cutaneous lesions. Persistent oral lesions, lack of effective oral hygiene, and plaque accumulation may increase the risk of long‐term periodontal disease. However, to our knowledge, no studies have evaluated the relationship between the presence of gingival MMP and periodontal health. The purpose of this study was to evaluate the possible impact of gingival pemphigoid lesions on the human periodontium.

Methods: Twenty patients with histologic confirmation of subepithelial separation with or without direct immunofluorescence testing were randomly chosen to participate in a study evaluating their periodontal status. Parameters evaluated included plaque score, gingival index, bleeding index, probing depths, recession, clinical attachment level, mobility, furcation involvement, number of missing teeth, and Machtei criteria, a previously defined criteria for periodontitis. Individuals matched with respect to age, gender, and smoking history were selected and evaluated for the same parameters.

Results: MMP patients had statistically significant larger mean gingival index scores than age, gender, and smoking history matched controls. Plaque scores, bleeding index, mobility, furcations, clinical attachment level, recession, and periodontal status did not show statistically significant differences between MMP and control patients. A statistically significant difference in plaque index was found when patients with MMP in treatment were compared to patients with MMP in remission. Among patients with MMP, those diagnosed >5 years in the past had statistically significantly greater Class I furcation involvement and recession on facial and lingual surfaces of teeth.

Conclusions: A relationship was found to suggest that patients with MMP exhibit more gingival inflammation than a control population. Among patients with MMP, patients currently in treatment have higher plaque indices than those in remission and not receiving treatment. Furthermore, when comparing patients with MMP who received a diagnosis >5 years in the past to those with a diagnosis in the past 5 years, statistically significantly greater Class I furcation and facial and lingual recession were measured. Long‐term follow‐up in this population may provide additional information as to periodontal progression in MMP versus control patients.
Esthetic Buccal Flap for Correction of Buccal Fenestration Defects During Flapless Immediate Implant Surgery
Authors: Steigmann Marius , Wang Hom‐Lay
Published: March 2006

Background: Clinically, it is a tremendous challenge to create natural gingival esthetics after immediate or delayed implant placement. Hence, flapless immediate implant surgery has been proposed to overcome the shortfalls of these techniques. Nonetheless, one of the major limitations for this technique is its inability to correct localized horizontal/vertical deficiency, dehiscence, or fenestration without jeopardizing esthetic outcomes. Therefore, the aim of this paper was to present a new flap design, the esthetic buccal flap (EBF), aimed at overcoming this potential problem while maintaining the optimal esthetic appearance.

Methods: Five consecutively EBF‐treated patients with simultaneous implant placement were included in this pilot case study. Clinical measurements were taken at the time of prosthesis insertion and 6 and 12 months after surgery. These included soft tissue height, papillae appearance, scar appearance, and mid‐buccal probing depth.

Results: Data obtained from this pilot case study showed that soft tissue height was preserved, and papillae appearance remained the same as at presurgery. No scar tissue was reported in any cases. Mid‐buccal probing depths remained consistent throughout the study.

Conclusion: The results indicate that EBF, together with simultaneously guided bone augmentation, allows clinicians to correct apical buccal fenestration defects while maintaining the supraosseous soft tissue during flapless immediate implant surgery.
Antibody Responses to Porphyromonas gingivalis Hemagglutinin A and Outer Membrane Protein in Chronic Periodontitis
Authors: Kobayashi Tetsuo , Kaneko Susumu , Tahara Tomoyuki , Hayakawa Mitsuo , Abiko Yoshimitsu , Yoshie Hiromasa
Published: March 2006

Background: Hemagglutinin and outer membrane protein (OMP) are major virulence factors associated with colonization of Porphyromonas gingivalis in the gingival crevice. The genes for the 200‐kDa antigenic protein (200‐kDa AP) and 40‐kDa OMP of P. gingivalis have been successfully cloned. Additionally, the 200‐kDa AP gene has been shown to constitute the hemagglutinin A (hagA) gene of P. gingivalis. Therefore, this study was constructed to evaluate the distributions and serum levels of immnoglobulin G (IgG) antibodies specific for 200‐kDa AP and 40‐kDa OMP in periodontitis patients.

Methods: Fifty patients with chronic periodontitis and 59 controls without periodontal destruction were enrolled in this study. We cloned the genes for 200‐kDa AP and 40‐kDa OMP from P. gingivalis and constructed the purified recombinant proteins. Serum levels of IgG subclass antibodies specific for both recombinant 200‐kDa and 40‐kDa OMP were determined in patients and controls by an enzyme‐linked immunosorbent assay (ELISA).

Results: The serum IgG subclass distribution for patients and controls was IgG1 > IgG4 > IgG2 > IgG3 in the anti‐200‐kDa AP response, which was almost identical to that in the anti‐40‐kDa OMP response. The patient group showed significantly higher serum IgG responses to the 40‐kDa OMP than the control group (P <0.01). In contrast, IgG subclass responses to the 200‐kDa AP were not different between the patients and controls. Serum levels of antibodies reactive with both 200‐kDa and 40‐kDa proteins did not have a significant association with mean probing depth.

Conclusion: These results suggested that serum IgG responses against P. gingivalis OMP rather than the hagA may be more active in chronic periodontitis.