Taste Aversion Learning Based on Swimming and Lithium Chloride Injection in Rats: Implications From Cross-familiarization Tests and Stimulus Selectivity1

In rats, swimming causes avoidance of the taste solution consumed immediately before the swimming. Several lines of research have shown that this taste avoidance reflects Pavlovian conditioned aversion based on correlations between the taste and swimming-induced nausea. The present research compared swimming-based taste aversion learning (TAL) with conventional TAL based on nausea-inducing lithium chloride (LiCl). By exploiting cross-familiarization techniques, Experiments 1A and 1B suggested that different physiological states are induced by swimming and LiCl. This claim was supported by Experiment 2, which reports stimulus selectivity in saccharin and sucrose aversions based on swimming and LiCl.     

Anticipatory nausea and vomiting among cancer patients: A Review

Abstract

Anticipatory nausea and vomiting (ANV), as a side-effect of cancer chemotherapy, is a well recognized phenomenon. The literature is reviewed for data on: prevalence rates, factors contributing to onset and psychological treatments used to attempt a remission in the symptoms. From the available evidence it appears that ANV is a substantial problem with one major review indicating an average combined prevalence of 32%. Although explicable using a conditioning model it has a complex aetiology with emotional and cognitive elements, as well as specific pharmacological factors, playing a role in onset. ANV appears to be responsive to psychologically-based treatment methods, with a good outcome overall. However, more process evaluation is needed in order to understand aetiologic and treatment mechanisms and to determine how best to treat cases of ANV with different aetiologies. It is considered that procedures for identifying and referring patients with ANV should be routinely incorporated into the care of cancer patients receiving repeated cycles of chemotherapy.     

A Mereological Challenge to Endurantism

In this paper, we argue that time travel is problematic for the endurantist. For it appears to be possible, given time travel, to construct a wall out of a single time travelling brick. This commits the endurantist to one of the following: (a) the wall is composed of the time travelling brick many times over; (b) the wall does not in fact exist at all; (c) the wall is identical to the brick. We argue that each of these options is unsatisfactory.     

Substitution effects in a generalized token economy with pigeons

Pigeons made repeated choices between earning and exchanging reinforcer‐specific tokens (green tokens exchangeable for food, red tokens exchangeable for water) and reinforcer‐general tokens (white tokens exchangeable for food or water) in a closed token economy. Food and green food tokens could be earned on one panel; water and red water tokens could be earned on a second panel; white generalized tokens could be earned on either panel. Responses on one key produced tokens according to a fixed‐ratio schedule, whereas responses on a second key produced exchange periods, during which all previously earned tokens could be exchanged for the appropriate commodity. Most conditions were conducted in a closed economy, and pigeons distributed their token allocation in ways that permitted food and water consumption. When the price of all tokens was equal and low, most pigeons preferred the generalized tokens. When token‐production prices were manipulated, pigeons reduced production of the tokens that increased in price while increasing production of the generalized tokens that remained at a fixed price. The latter is consistent with a substitution effect: Generalized tokens increased and were exchanged for the more expensive reinforcer. When food and water were made freely available outside the session, token production and exchange was sharply reduced but was not eliminated, even in conditions when it no longer produced tokens. The results join with other recent data in showing sustained generalized functions of token reinforcers, and demonstrate the utility of token‐economic methods for assessing demand for and substitution among multiple commodities in a laboratory context.     

Behavior analysis and neuroscience: Complementary disciplines

Behavior analysis and neuroscience are disciplines in their own right but are united in that both are subfields of a common overarching field—biology. What most fundamentally unites these disciplines is a shared commitment to selectionism, the Darwinian mode of explanation. In selectionism, the order and complexity observed in nature are seen as the cumulative products of selection processes acting over time on a population of variants—favoring some and disfavoring others—with the affected variants contributing to the population on which future selections operate. In the case of behavior analysis, the central selection process is selection by reinforcement; in neuroscience it is natural selection. The two selection processes are inter‐related in that selection by reinforcement is itself the product of natural selection. The present paper illustrates the complementary nature of behavior analysis and neuroscience through considering their joint contributions to three central problem areas: reinforcement—including conditioned reinforcement, stimulus control—including equivalence classes, and memory—including reminding and remembering.     

Rapid acquisition of choice and timing and the provenance of the terminal-link effect

Eight pigeons responded in a concurrent-chains procedure in which terminal-link schedules changed pseudorandomly across sessions. Pairs of terminal-link delays either summed to 15 s or to 45 s. Across sessions, the location of the shorter terminal link changed according to a pseudorandom binary sequence. On some terminal links, food was withheld to obtain start and stop times, measures of temporal control. Log initial-link response ratios stabilized within the first half of each session. Log response ratio was a monotonically-increasing but nonlinear function of programmed log terminal-link immediacy ratio. There was an effect of absolute terminal-link duration on log response ratio: For most subjects, preference for the relatively shorter terminal-link delay was stronger when absolute delays were long than when absolute delays were short. Polynomial regressions and model comparison showed that differences in degree of nonlinearity, not in sensitivity to log immediacy ratio, produced this effect. Temporal control of stop times was timescale invariant with scalar variability, but temporal control of start times was not consistent across subjects or terminal-link durations.     

Is Laughter the Best Medicine? Humor, Laughter, and Physical Health

This article examines research evidence for the popular idea that humor and laughter have beneficial effects on physical health. Potential theoretical mechanisms for such effects are discussed first. Empirical evidence for beneficial effects of humor and laughter on immunity, pain tolerance, blood pressure, longevity, and illness symptoms is then summarized. Overall, the evidence for health benefits of humor and laughter is less conclusive than commonly believed. Future research in this area needs to be more theoretically driven and methodologically rigorous.     

OBSERVING RESPONSES AND SERIAL STIMULI: SEARCHING FOR THE REINFORCING PROPERTIES OF THE S−

The control exerted by a stimulus associated with an extinction component (S−) on observing responses was determined as a function of its temporal relation with the onset of the reinforcement component. Lever pressing by rats was reinforced on a mixed random-interval extinction schedule. Each press on a second lever produced stimuli associated with the component of the schedule in effect. In Experiment 1 a response-dependent clock procedure that incorporated different stimuli associated with an extinction component of a variable duration was used. When a single S− was presented throughout the extinction component, the rate of observing remained relatively constant across this component. In the response-dependent clock procedure, observing responses increased from the beginning to the end of the extinction component. This result was replicated in Experiment 2, using a similar clock procedure but keeping the number of stimuli per extinction component constant. We conclude that the S− can function as a conditioned reinforcer, a neutral stimulus or as an aversive stimulus, depending on its temporal location within the extinction component.