Social overstimulation reduces subsequent aggression in Betta splendens

This paper examines the waning of intense aggressive behaviors in Siamese fighting fish subjected to continuous visual social stimulation. Damaging biting during subsequent fighting was dramatically reduced in fish which had been surrounded for several weeks by conspecifics, even though the overstimulated fish performed only opercular and fin displays to the fish surrounding them, not biting. The latency to opercular display was diminished, but the rate once opercular display began was not significantly different. In the 18 encounters observed, a socially overstimulated fish never dominated a control fish. This result suggests a visually mediated mechanism, which reduces biting tendency when there is prolonged, inescapable visual exposure to mildly aggression-releasing stimuli similar to those which trigger biting in live encounters. © 1994 Wiley-Liss, Inc.     

On Modal Logics Characterized by Models with Relative Accessibility Relations: Part II

This work is divided in two papers (Part I and Part II). In Part I, we introduced the class of Rare-logics for which the set of terms indexing the modal operators are hierarchized in two levels: the set of Boolean terms and the set of terms built upon the set of Boolean terms. By investigating different algebraic properties satisfied by the models of the Rare-logics, reductions for decidability were established by faithfully translating the Rare-logics into more standard modal logics (some of them contain the universal modal operator).In Part II, we push forward the results from Part I. For Rare-logics with nominals (present at the level of formulae and at the level of modal expressions), we show that the constructions from Part I can be extended although it is technically more involved. We also characterize a class of standard modal logics for which the universal modal operator can be eliminated as far as satifiability is concerned. Although the previous results have a semantic flavour, we are also able to define proof systems for Rare-logics from existing proof systems for the corresponding standard modal logics. Last, but not least, decidability results for Rare-logics are established uniformly, in particular for information logics derived from rough set theory.Since this paper is the continuation of Part I, we do not recall here the definitions of Part I although we refer to them.     

STIMULUS EFFECTS ON LOCAL PREFERENCE: STIMULUS—RESPONSE CONTINGENCIES,STIMULUS—FOOD PAIRING,AND STIMULUS—FOOD CORRELATION

Four pigeons were trained in a procedure in which concurrent‐schedule food ratios changed unpredictably across seven unsignaled components after 10 food deliveries. Additional green‐key stimulus presentations also occurred on the two alternatives, sometimes in the same ratio as the component food ratio, and sometimes in the inverse ratio. In eight experimental conditions, we varied the contingencies surrounding these additional stimuli: In two conditions, stimulus onset and offset were noncontingent; in another two, stimulus onset was noncontingent, and offset was response contingent. In four conditions, both stimulus onset and offset were contingent, and in two of these conditions the stimulus was simultaneously paired with food delivery. Sensitivity to component food ratios was significantly higher when stimulus onset was response contingent compared to when it was noncontingent. Choice changes following food delivery were similar in all eight conditions. Choice changes following stimuli were smaller than those following food, and directionally were completely determined by the food‐ratio:stimulus‐ratio correlation, not by the stimulus contingency nor by whether the stimulus was paired with food or not. These results support the idea that conditional reinforcers may best be viewed as signals for next‐food location rather than as stimuli that have acquired hedonic value, at least when the signals are differential with respect to future conditions.     

Differential reinforcement of alternative behavior increases resistance to extinction: clinical demonstration, animal modeling, and clinical test of one solution

Basic research with pigeons on behavioral momentum suggests that differential reinforcement of alternative behavior (DRA) can increase the resistance of target behavior to change. This finding suggests that clinical applications of DRA may inadvertently increase the persistence of target behavior even as it decreases its frequency. We conducted three coordinated experiments to test whether DRA has persistence-strengthening effects on clinically significant target behavior and then tested the effectiveness of a possible solution to this problem in both a nonhuman and clinical study. Experiment 1 compared resistance to extinction following baseline rates of reinforcement versus higher DRA rates of reinforcement in a clinical study. Resistance to extinction was substantially greater following DRA. Experiment 2 tested a rat model of a possible solution to this problem. Training an alternative response in a context without reinforcement of the target response circumvented the persistence-strengthening effects of DRA. Experiment 3 translated the rat model into a novel clinical application of DRA. Training an alternative response with DRA in a separate context resulted in lower resistance to extinction than employing DRA in the context correlated with reinforcement of target behavior. The value of coordinated bidirectional translational research is discussed.     

A decision model for steady-state choice in concurrent chains

Grace and McLean (2006) proposed a decision model for acquisition of choice in concurrent chains which assumes that after reinforcement in a terminal link, subjects make a discrimination whether the preceding reinforcer delay was short or long relative to a criterion. Their model was subsequently extended by Christensen and Grace (2008, 2009a, 2009b) to include effects of initial- and terminal-link duration on choice. We show that an expression for steady-state responding can be derived from the decision model, which enables a model for choice that provides an account of archival data that is equal or superior to the contextual choice model (Grace, 1994) and hyperbolic value-added model (Mazur, 2001) in terms of goodness of fit, parsimony, and parameter invariance. The success of the steady-state decision model validates the strategy of understanding acquisition phenomena as a bridge toward explaining choice at the molar level.     

Dual effects on choice of conditioned reinforcement frequency and conditioned reinforcement value

Pigeons were presented with a concurrent‐chains schedule in which the total time to primary reinforcement was equated for the two alternatives (VI 30 s VI 60 s vs. VI 60 s VI 30 s). In one set of conditions, the terminal links were signaled by the same stimulus, and in another set of conditions they were signaled by different stimuli. Choice was in favor of the shorter terminal link when the terminal links were differentially signaled but in favor of the shorter initial link (and longer terminal link) when the terminal links shared the same stimulus. Preference reversed regularly with reversals of the stimulus condition and was unrelated to the discrimination between the two terminal links during the nondifferential stimulus condition. The present results suggest that the relative value of the terminal‐link stimuli and the relative rate of conditioned reinforcer presentation are important influences on choice behavior, and that models of conditioned reinforcement need to include both factors.     

Examining the generality of children's preference for contingent reinforcement via extension to different responses, reinforcers, and schedules

Studies that have assessed whether children prefer contingent reinforcement (CR) or noncontingent reinforcement (NCR) have shown that they prefer CR. Preference for CR has, however, been evaluated only under continuous reinforcement (CRF) schedules. The prevalence of intermittent reinforcement (INT) warrants an evaluation of whether preference for CR persists as the schedule of reinforcement is thinned. In the current study, we evaluated 2 children's preference for contingent versus noncontingent delivery of highly preferred edible items for academic task completion under CRF and INT schedules. Children (a) preferred CR to NCR under the CRF schedule, (b) continued to prefer CR as the schedule of reinforcement became intermittent, and (c) exhibited a shift in preference from CR to NCR as the schedule became increasingly thin. These findings extend the generality of and provide one set of limits to the preference for CR. Applied implications, variables controlling preferences, and future research are discussed.     

Increasing seat belt use in service vehicle drivers with a gearshift delay

This study evaluated a device that prevents drivers from shifting vehicles into gear for up to 8 s unless seat belts are buckled. Participants were 101 commercial drivers who operated vans, pickups, or other light trucks from the U.S. and Canada. The driver could escape or avoid the delay by fastening his or her seat belt before shifting out of park. Unbelted participants experienced either a constant delay (8 s) or a variable delay (M = 8 s). A 16‐s delay was introduced for those U.S. drivers who did not show significant improvement. Seat belt use increased from 48% to 67% (a 40% increase) for U.S. drivers and from 54% to 74% (a 37% increase) for Canadian drivers. The fixed delay was more effective for U.S. drivers than the variable delay, but there was no difference between these two delay schedules for Canadian drivers. After the driver fastened his or her seat belt, it tended to remain fastened for the duration of the trip.     

Increasing response diversity in children with autism

Repetitive and invariant behavior is a diagnostic feature of autism. We implemented a lag reinforcement schedule to increase response diversity for 6 participants with autism aged 6 to 10 years, 4 of whom also received prompting plus additional training. These procedures appeared to increase the variety of building-block structures, demonstrating that an intervention that includes differential reinforcement can increase response diversity for children with an autism spectrum disorder.     

Spoon distance fading with and without escape extinction as treatment for food refusal

Little is known about the characteristics of meals that serve as motivating operations (MOs) for escape behavior. In the current investigation, we showed that the distance at which a therapist held a spoon from a child's lips served as an MO for escape behavior. Based on these results, we implemented spoon distance fading, compared fading with and without escape extinction (EE), and compared fading plus EE to EE alone. Initially, inappropriate mealtime behavior decreased during fading, but this effect was not maintained as fading progressed. Inappropriate mealtime behavior was lower initially when we combined fading and EE relative to EE alone, but acceptance increased more rapidly with EE than with fading plus EE. These results suggest that a number of mealtime characteristics might function as MOs for escape behavior and that analyses of MOs may be useful for developing treatments for food refusal.