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The extent to which a stimulus exerts control over behavior depends largely on its informativeness. However, when reinforcers have discriminative properties, they often exert less control over behavior than do other less reliable stimuli such as elapsed time. We investigated why less reliable cues in the present often overshadow stimulus control by more reliable cues presented in the recent past, by manipulating the reliability and duration of stimulus presentations. Five pigeons worked on a modified concurrent schedule in which the location of the response that produced the last reinforcer was a discriminative stimulus for the likely time and location of the next reinforcer. In some conditions, either the location of the previous reinforcer, or the location of the next reinforcer, was signaled by a red key light. This stimulus was either Brief, occurring for 10 s starting a fixed time after the most recent reinforcer, or Extended, being present at all times between food deliveries. Brief and Extended stimuli that signaled the same information had a similar effect on choice when they were present, but control by Brief stimuli weakened as time since stimulus offset elapsed. Control was divided among stimuli in the present and recent past according to the apparent reliability of the information signaled about the next reinforcer. More reliable stimuli in the present degraded, but did not erase, control by less reliable stimuli presented in the recent past. Thus, we conclude that less reliable stimuli in the present control behavior to a greater degree than do more reliable stimuli in the recent past because these more reliable stimuli are forgotten, and hence their relation to the likely availability of food cannot be discriminated.

Obesity is a major public health problem, which, like many forms of addiction, is associated with an elevated tendency to choose smaller immediate rather than larger delayed rewards, a response pattern often referred to as excessive delay discounting. Although some accounts of delay discounting conceptualize this process as impulsivity (placing the emphasis on overvaluing the smaller immediate reward), others have conceptualized delay discounting as an executive function (placing the emphasis on delayed rewards failing to retain their value). The present experiments used a popular animal model of obesity that has been shown to discount delayed rewards at elevated rates (i.e., obese Zucker rats) to test two predictions that conceptualize delay discounting as executive function. In the first experiment, acquisition of lever pressing with delayed rewards was compared in obese versus lean Zucker rats. Contrary to predictions based on delay discounting as executive function, obese Zucker rats learned to press the lever more quickly than controls. In the second experiment, progressive ratio breakpoints (a measure of reward efficacy) with delayed rewards were compared in obese versus lean Zucker rats. Contrary to the notion that obese rats fail to value delayed rewards, the obese Zucker rats' breakpoints were (at least) as high as those of the lean Zucker rats.

Multilevel modeling provides the ability to simultaneously evaluate the discounting of individuals and groups using indifference point data. After considering the conditions when weaknesses emerge in estimating individual discounting as a prelude to estimating group discounting, examples are provided that indicate that multilevel modeling improves estimation in the presence of variability and missing data, and when trying to fit two‐parameter discounting functions. Concrete examples of how to fit nonlinear multilevel models are provided to help researchers in the adoption of these methods.

Professionals recommend parents engage in distracting activities to mitigate negative effects of inconsolable infant crying (e.g., Deyo, Skybo, & Carroll, 2008; Goulet et al., 2009). We evaluated the availability of alternative activities on six undergraduates’ tolerance for a recorded infant cry; three students tolerated the cry longer when distracting activities were available. Our results show that distracting activities could decrease the aversiveness of inconsolable infant crying for some individuals; additional research in natural caregiving situations will help determine the generality and social validity of this finding.

The unique relationship between dog and owner has been demonstrated in several experimental procedures, including tests in which dogs are left alone or with a stranger, tests of dogs’ appeasement or social approach when petted by their owner or a stranger, and their ability to learn when taught by their owner or a stranger. In all cases, dogs responded differently to their owner, which has been referred to as a specific attachment, and likely a product of a prolonged history of reinforcement. In the current study, we used a concurrent choice paradigm in which dogs could interact with two people, both of whom provided the same petting interaction, to test whether owned dogs would prefer their owner over a stranger and whether the familiarity of the testing context would influence preference. We also investigated whether shelter and owned dogs tested with two strangers would show a preference between strangers and whether that preference would be similar in magnitude to any preference between the owner and stranger. Owned dogs preferred to interact with their owners when in an unfamiliar context, but allocated more time to the stranger in a familiar context. Both shelter and owned dogs tested with two strangers showed a magnitude of preference for one stranger over the other similar to owned dogs’ preference for owners in an unfamiliar context. These results parallel what has been found in strange situation tests with owned dogs tested with their owners, but the strength of preference shown for one of two strangers indicates dogs can form a preference for one person quickly.

Despite the success of exposure‐based psychotherapies in anxiety treatment, relapse remains problematic. Resurgence, the return of previously eliminated behavior following the elimination of an alternative source of reinforcement, is a promising model of operant relapse. Nonhuman resurgence research has shown that higher rates of alternative reinforcement result in faster, more comprehensive suppression of target behavior, but also in greater resurgence when alternative reinforcement is eliminated. This study investigated rich and lean rates of alternative reinforcement on response suppression and resurgence in typically developing humans. In Phase 1, three groups (Rich, n = 18; Lean, n = 18; Control, n = 10) acquired the target response. In Phase 2, target responding was extinguished and alternative reinforcement delivered on RI 1 s, RI 3 s, and extinction schedules, respectively. Resurgence was assessed during Phase 3 under extinction conditions for all groups. Target responding was suppressed most thoroughly in Rich and partially in Lean. Target responding resurged in the Rich and Lean groups, but not in the Control group. Between groups, resurgence was more pronounced in the Rich group than the Lean and Control groups. Clinical implications of these findings, including care on the part of clinicians when identifying alternative sources of reinforcement, are discussed.

In this study, we manipulated mastery criterion form (rolling or block) and stringency (across 6 or 12 trials) and measured the emergence of derived relations. College students learned neuroanatomy equivalence classes and experienced one of two rolling mastery criteria (6 or 12 consecutive correct responses) or a block mastery criterion (12 trials in a block) during training. The study found that block and rolling mastery criteria produced similar outcomes. Effectiveness was hampered when the criterion was less stringent.

Research on stimulus–stimulus pairing to induce novel vocalizations in nonverbal children has typically employed response‐independent pairing (RIP) procedures to condition speech sounds as reinforcers. The purpose of the present study was to evaluate the effects of a response‐contingent pairing (RCP) procedure on the vocalizations of three nonverbal boys diagnosed with autism spectrum disorder. During RCP, adult‐delivered sounds that were either paired with a preferred item (target sounds) or not (nontarget sounds) were presented contingent on a button‐press response. In Experiment 1, RCP was compared with an RIP procedure, in which the timing of sound presentations was yoked to the preceding RCP session. RCP produced a greater effect on all participants' target vocalizations than RIP. Experiment 2 demonstrated the effects of differential reinforcement of the vocalizations induced in Experiment 1. The results suggest that RCP may develop vocalizations more reliably than RIP procedures.

The purpose of this study was to investigate the effects of signaled transitions from relatively rich to lean conditions of food reinforcement on drinking concurrently available water or sucrose‐sweetened water in rats. Past research demonstrated that these negative incentive shifts produce behavioral disruption in the form of extended pausing on fixed‐ratio schedules. Four male Long‐Evans rats operated on a two‐component multiple fixed‐ratio fixed‐ratio schedule. In one manipulation, the ratio was held constant and the components arranged either a large six‐pellet reinforcer (rich) or small one‐pellet reinforcer (lean). In a second manipulation, the components both produced a one‐pellet reinforcer but differed in terms of the ratio requirement, with the rich and lean conditions corresponding to relatively small and large ratios. In both manipulations, components were pseudorandomly presented to arrange four transitions signaled by retractable levers: lean‐to‐lean, lean‐to‐rich, rich‐to‐rich, and rich‐to‐lean (the negative incentive shift). During experimental conditions, a bottle with lickometer was inserted in the chamber, providing concurrent access either to tap water or a 10% sucrose solution. The negative incentive shift produced considerably more drinking than the other transitions in all rats during both manipulations. The level of drinking was not polydipsic; rather, it appears that the negative incentive shift enhanced the value of concurrently available reinforcers relative to food reinforcement.