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Response disequilibrium is the perturbation of unconstrained behavior with a contingency. For example, the imposition of advertisements before or after viewing TikTok videos. The purpose of this laboratory analogue was to determine the effects of two such response disequilibrium conditions: (1) which required participants to view 5 s increments of advertisements to access 2 s increments of TikTok videos and (2) which required participants to view 5 s increments of TikTok videos to access 15 s increments of advertisements. The disequilibrium condition in (1) is called a response deficit due to the restricted access to TikTok videos relative to baseline while (2) is called a response excess due to the overabundance of advertisements relative to baseline. Additionally, participants had access to a third activity that was freely available throughout. Participants could browse images of TikTok video thumbnails while in deficit and excess. As predicted, participants increased their viewing of advertisements when TikTok was in deficit and decreased their viewing of TikTok when advertisements were in excess. Furthermore, some participants substituted TikTok with browsing during the excess of advertisements. This investigation has implications for a behavioral economic analysis of social media use and the contingency management of time spent on these platforms. • Time spent viewing advertisements increased when TikTok videos were in deficit. • Time spent viewing TikTok videos decreased when advertisements were in excess. • Time spent browsing video thumbnails increased when advertisements were in excess. [ABSTRACT FROM AUTHOR]

Two experiments examined the hedonic responses conditioned to odor cues in the phenomenon of taste-potentiated odor aversion. Experiment 1 analyzed the microstructure of licking behavior during voluntary consumption. A tasteless odor (amyl acetate) was delivered to rats either diluted in water or mixed with saccharin before being injected with LiCl. At test, subjects which had received the odor-taste compound during conditioning showed both lower odor consumption and lick cluster size, a result indicating an increased negative evaluation of the odor. Experiment 2 examined the orofacial reactions elicited by the odor as index of its hedonic impact. During conditioning, the rats were intraorally infused with either the odor alone or the odor-saccharin compound before being injected with LiCl. At test, they were infused with the odor and their orofacial responses video recorded. More aversive orofacial responses were elicited by the odor cue in rats that had compound conditioning, again a result indicating a strengthened negative hedonic reactivity compared to animals experiencing odor aversion conditioning alone. Taken together, these results indicate that taste-mediated potentiation of odor aversion conditioning impacts on the acquisition of conditioned hedonic reactions as well as consumption. • Conditioned hedonic responses in taste-potentiated odor aversion. • Odor-taste compound conditioning enhances negative hedonic reactivity to the odor. • Odor hedonics assessed by licking behavior analysis and orofacial reactivity. • Integration of olfactory and gustatory cues in flavor aversion learning. [ABSTRACT FROM AUTHOR]

Across three experiments, participants underwent conditioning sequences where the self-referential term I AM (Conditioned Stimulus, or CS+) or a scrambled counterpart M IA (CS-) was paired with either neutral (Unconditioned Stimulus, or US-) or positive attributes (US+). CS and US were presented under subliminal and/or visible conditions. A normalized indicator of affective shift and an explicit self-esteem measure were deployed as outcome measures. In Experiment 1 (N = 60), subliminal CS+ followed by visible US+ produced a significant affective shift only. Experiment 2 (N = 59) presented CS and US under subliminal conditions, which did not influence either outcome measure. In Experiment 3 (N = 60), visible CS appeared with visible US, which resulted in a significant effect on explicit self-esteem only. These findings highlight the central roles of CS and/or US visibility towards influencing reported affect and self-esteem. We theorize that configural components of subliminally presented stimuli can become perceptually encoded and influence self-related affect non-consciously. • Pairing subliminal self-referential terms with visible attributes exclusively enhanced affect across Experiment 1. • Pairing visible self-referential terms with visible attributes exclusively enhanced self-esteem across Experiment 3. • Differential effects on affect and self-esteem were governed by differential awareness of self-referential terms. • As per realist learning theory, elements and their configurations were non-consciously encoded. [ABSTRACT FROM AUTHOR]

• Decision-making is a characteristic of intelligence not previously observed in snails. • We demonstrate that when hungry enough snails detect and eat novel substances but reject familiar ones if sated. • This species can therefore be used as a model for studying the cognitive capacities of higher species. • The fact that snails decide whether to eat a given food or not implies that they may be misled. • This could be helpful for a more efficient deployment of baits that are currently used to protect crops. The foraging behaviour of gastropod molluscs usually involves complex decisions that provide a model for the study of high-order cognitive processes. Land snails tested for food-finding in the laboratory, however, have shown an invariable feeding pattern: novel foods are mostly missed (i.e. just found by chance) whilst familiar foods, due to a type of conditioned attraction, are always located and ingested. This effect, known as Food-attraction conditioning , has led to the conclusion that, regardless of their hunger level, land snails are both willing to eat anything at any moment and also blind to the odours of novel foods. An alternative account of these findings emerges from the fact that the snails are usually tested whilst in a moderate state of hunger, so that they benefit from feeding on known foods but not from taking the risk of feeding on those that are unknown. The present experiments suggest that it is the case. Snails of the invasive species Theba pisana were tested for food-finding according to their seasonal cycle in a laboratory located in their native Mediterranean region. Subjects collected at the beginning of their aestivation period succeed in locating novel food items after being deprived for a long period (45 days), but ignored a conditioned food when they were sated with this food at the end of their lethargy. The results allow us to conclude that the feeding behaviour of snails is the product of a complex cost-benefit analysis in which their motivational state and the stimuli they perceive (and the memory of such stimuli), are evaluated. Finally, we anticipate that these results will be of use in increasing the efficiency of current baits employed for the protection of crops. [ABSTRACT FROM AUTHOR]

• Participants associated sensors with attacking spaceships in a video game while being monitored with an eye tracker. • Participants showed sign tracking and attended to the predictive sensors. • Participants showed a conditioned visual search and attended to the areas where the spaceship would appear. • Pupillary dilation responses were observed, but did not appear to be contingent on stimulus covariations. • Implications of outcome searching for studies of learning, attention, and goal anticipation are discussed. Two experiments used eye tracking to examine visual searching for expected outcomes in humans during an associative-learning task. In both, participants learned to press keys on a keyboard to activate weapons to repel invading spaceships in the presence of predictive "sensors." In both experiments, eye tracking showed that participants came to direct their overt visual attention to the portions of the screen where the spaceship would arrive during the presentation of the sensor in a cue-specific manner. Participants also directed attention to the weapon that was used to repel the spaceship. The same results were observed regardless of whether participants were responding on the keyboard, or not (Experiment 2). Pupil dilations occurred to the appearance of the spaceship from the first trial and occurred to the predictive sensor stimuli on later trials in both experiments, suggesting that they might be conditioned responses. In Experiment 2 participants again looked for the expected outcome, but dilations to the predictive stimuli were shown to be an artifact of responding and not due to conditioning. The discussion involves the implications for investigating attention to predictive stimuli using eye trackers, roles of context in behavior, and the utility of outcome searching and pupil dilations as indexes of learning. [ABSTRACT FROM AUTHOR]

Previous nonhuman studies have reported that sign-tracking to a conditioned stimulus (CS) is increased when the intertrial interval (ITI) duration is increased. Separate studies indicate that individual differences in sign-tracking (vs. goal-tracking) at a fixed ITI (and CS duration) is predictive of the conditioned reinforcer efficacy of the CS. The present study evaluates, for the first time, if increasing the ITI increases rats' sign-tracking and the conditioned reinforcing efficacy of the CS. Forty-five female rats were randomly assigned to one of three groups that completed appetitive Pavlovian training with ITIs of 14, 24, or 96 s. Subsequently, they completed tests of conditioned reinforcement. Replicating previous findings, longer ITIs increased sign-tracking to a lever-CS and, extending the literature, conditioned reinforcer efficacy of that CS was highest at the longest ITI used during Pavlovian training. Implications for behavioral interventions using conditioned reinforcement are discussed. • Sign-tracking is predictive of conditioned reinforcer efficacy. • Intertrial intervals during Pavlovian training were manipulated (14, 24, or 96 s). • Longer intertrial intervals systematically increase sign-tracking. • Longer intertrial intervals yielded the most effective CS/conditioned reinforcer. [ABSTRACT FROM AUTHOR]

• Early-life auditory experience and the type of song stimuli on the Zenk response in the auditory forebrain of female zebra finches. • Unlearned response biases to conspecific song elements depend on previous auditory experience. • Early experience appears to modulate the expression of innate biases. The auditory forebrain regions caudo-medial nidopallium (NCM) and caudo-medial mesopallium (CMM) of songbirds exhibit differential expression of the immediate-early gene ZENK in response to playback of different song stimuli, and dependent on early-life auditory experience. Similarly, song preferences depend both on auditory experience and unlearned biases for particular song features. We explored the contributions of early-life auditory experience and the type of song stimuli on the Zenk response in the auditory forebrain of female zebra finches. Females were raised in three different early tutoring conditions: conspecific tutors that sang isolate song, heterospecific tutors, or conspecific tutors that sang wild-type song. At maturity, these females were exposed to one of five different playback conditions: wild-type song, isolate song, tutor song, heterospecific song, or white noise. Subsequently, the number of cells immunoreactive for ZENK in CMM and NCM was measured. We predicted that birds exposed to conspecific song early in life, and during the song playback in adulthood, would have the highest neural response. Instead, we found that the Zenk response varied across playback conditions with the highest response to conspecific wild-type and conspecific isolate song. In addition, we found a main effect of tutoring, with the lowest overall Zenk response in females tutored by males singing isolate song. Most importantly, there was a significant interaction in that females tutored by wild-type conspecific or heterospecific songs showed a similar increased response to zebra finch songs (wild-type or isolate), but females tutored by isolate song showed no differential response to conspecific song and only showed elevated Zenk response to the particular songs they were tutored with. Combined, our results indicate that unlearned response biases to conspecific song elements depend on previous auditory experience. That is, early experience appears to modulate the expression of innate biases. [ABSTRACT FROM AUTHOR]

Highlights • Chickadees fail to modify behaviour in response to temperature cues. • Modulation of behaviour is essential for the exploitation of resources. • Previously observed population differences are likely due to local adaptation. Abstract Birds overwintering at northern latitudes face challenging environments in which refined cognitive and behavioural responses to environmental stimuli could be a benefit. Populations of the same species from different latitudes have been shown to differ in their cognitive and behavioural responses, and these differences have been attributed to local adaptation. However, individuals overwintering at intermediate latitudes experience great breadth and variation in environmental conditions, and thus it is reasonable that these individuals would alter their responses based on current conditions. To determine within-species responses to environmental conditions we sampled birds from a single population at an intermediate latitude and assessed their problem solving abilities and their responses to novelty. We held birds overwinter in one of three experimental temperature regimes and assessed problem solving abilities and responses to novel stimuli in the spring. We found that overwinter temperature had no effect on problem solving ability. We also show that overwinter temperature had no effect on an individual's response to novelty. These findings strengthen the argument that differences in these behaviours seen at the population level are in fact driven by local adaptation, and that current environmental condition may have limited effects on these behaviours. [ABSTRACT FROM AUTHOR]

Highlights • Reviews the current status of the behavior system for sexual learning. • In addition to reviewing research with quail (which was the focus of prior paper), in this treatment research with rats is also incorporated into the characterization of the behavior system. • Unlike prior papers which dealt primarily with sexual learning in males, in this review we also discuss in detail sexual learning in females. • For the first time the characterization of the sexual learning system includes detailed information on how learning facilitates fertilization and reproductive success. • Although much progress has been made in characterizing the sexual learning system, we include an extensive section discussing areas for future research. • A new perspective on how sexual learning can contribute to evolutionary change is included. Abstract In this paper we review and update evidence relevant to formulating a behavior system for sexual learning. We emphasize behavioral rather than neurobiological evidence and mechanisms. Our analysis focuses on three types of responses or response modes: general search, focal search, and consummatory or copulatory behavior. We consider how these response modes are influenced by three categories of stimuli: spatially distributed contextual cues, arbitrary localized stimuli, and species-typical cues provided by the sexual partner. We characterize behavior control by these types of stimuli before and after various Pavlovian conditioning procedures in which the unconditioned stimulus is provided by copulation with a sexual partner. The results document extensive Pavlovian modifications of sexual behavior. These conditioning effects reflect new conditioned responses that come to be elicited by various categories of stimuli. In addition, the conditioning of contextual cues and localized stimuli facilitate sexual responding to species-typical cues. Thus, learning experiences enhance how the species-typical cues of a sexual partner stimulate sexual behavior. These modulatory conditioning effects not only produce significant behavioral changes but also increase rates of fertilization of eggs and numbers of offspring produced. These latter findings suggest that sexual learning can lead to differential reproductive success, which in turn can contribute to evolutionary change. [ABSTRACT FROM AUTHOR]

Highlights • Definitions and descriptions of Pavlovian conditioning refer frequently to "neutral stimuli". • Evidence suggests that would-be conditioned stimuli (CSs) are not neutral prior to conditioning. • Influence of CS type on conditioned responses is consistent with a behavior systems account. • Pavlovian conditioning does not require a neutral stimulus. • Neutral stimuli may not even exist. Abstract For almost a century, the idea that neutral stimuli acquire meaning by association with biologically-relevant stimuli has been a fixture of psychologists' descriptions of Pavlovian conditioning. A potential problem with this view is that there exists unambiguous data against the notion that conditioned stimuli (CSs) are neutral prior to conditioning. The results of studies that examined the effect of the type of CS on the form of the conditioned response (CR) are consistent with a behavior systems framework, which supposes that the physical characteristics of the CS interact with an animal's evolved stimulus sensitivities and response tendencies related to the unconditioned stimulus (US) and other features of the training situation to influence the form of the CR. Empirically, Pavlovian conditioning does not require a neutral stimulus. Conceptually, it is unclear that neutral stimuli even exist. Definitions and descriptions of Pavlovian conditioning should avoid referring to neutral stimuli. [ABSTRACT FROM AUTHOR]

When a target conditioned stimulus (CS A) is paired with an unconditioned stimulus in the presence of a second, conditioned stimulus (CS B) during compound conditioning trials, the associative strength of CS B can influence the magnitude of the conditioned response (CR) to CS A. For example, extinction of the competing, nontarget CS B can influence the CR to CS A. An enhancement of the CR to the target CS A due to extinction of the nontarget CS B after compound conditioning is sometimes referred to as “recovery from overshadowing” – a type of retrospective revaluation. The present experiments examined retrospective revaluation effects using a conditioned taste aversion procedure. The experiments obtained an effect on the CR to CS A following extinction of CS B. The results are discussed with respect to the comparator hypothesis, within-compound associations, and retrieval as well as other relationships between the target CS and nontarget CS. [ABSTRACT FROM AUTHOR]

This study assesses the recovery of the conditioned response (CR) due to a contextual change (renewal effect) in the Cornu aspersum , using the appetitive Pavlovian Conditioning of Tentacle Lowering procedure. Snails experienced an odorous conditioned stimulus (CS) paired with food (conditioning), followed by the exposition to the CS without any consequence (extinction). Then, they were exposed to the CS in a different context from the extinction one (renewal test). The contexts were three types of illumination. In Experiment 1a, the conditioning was performed in context A, the extinction was conducted in context B and the renewal test was performed in context A. For Experiment 1b, the conditioning and extinction were conducted in context A and renewal was performed in context B. In Experiment 1c, three dissimilar contexts were used for each experimental phase: context A for the conditioning, context B for the extinction and context C for the renewal. In Experiment 2, the renewal magnitude was compared among the three paradigms (ABA, AAB and ABC). Experiments 1a, 1b and 1c showed a recovery of the CR when subjects experienced a contextual change and Experiment 2 showed equivalent levels of renewal in the three paradigms. Learning processes and theories involved are discussed. • This study provides a replica of ABA renewal and the first evidence of AAB and ABC renewal in invertebrates. • The light can be used as context cue. • Experiment 2 show an equivalent magnitude of the renewal effect among the three paradigms. • The explanations of the Acquisition and the Retrieval theories about the renewal effect are debated. • The invertebrates nervous system can process the context as well as the vertebrates one. [ABSTRACT FROM AUTHOR]

• Earthworms (Aporrectodea longa) were conditioned with an odorous conditioned stimulus. • Group paired showed more conditioned responses than groups backward and unpaired. • This experiment supports a method to study cue competition learning in earthworms. The study of associative learning in invertebrates has become an essential tool for exploring their cognitive abilities and for studying the biological bases of learning and memory. In this experiment with earthworms, we paired a rose odour conditioned stimulus (CS) with a bright light unconditioned stimulus (US). After these pairings, the head retraction response — which is initially elicited by the bright light — is eventually evoked by the rose odour. This is the first demonstration of classical conditioning of an odour in earthworms (vibrations are usually employed as CSs), using a procedure that enables us to rule out an explanation in terms of pseudoconditioning. [ABSTRACT FROM AUTHOR]

The consolidation of behavioral sequences into relatively ballistic habits is thought to involve the formation of stimulus – response associations. Typically, the stimuli in these associations are assumed to be exteroceptive, i.e., external to the organism. However, responses, themselves, also possess stimulus properties that can mediate behavior. Indeed, these “proprioceptive cues” have long been hypothesized to underlie habit formation (Hull, 1934a, 1934b). One such stimulus involves the time durations between responses – a stimulus termed interresponse time (IRT). We hypothesize that IRTs can come to serve as stimuli that differentially control response elements during habit formation. To examine this hypothesis we report on two experiments that asked whether CD-1 mice utilize IRTs to structure behavior in a two-choice environment. In experiment 1, eight mice were exposed to a free-operant concurrent variable-interval (VI) 30-s VI 60-s reinforcement schedule. We found that switch and stay responses were differentially correlated with IRT durations. In Experiment 2 we directly and differentially reinforced stay/switch responses based on IRT durations in a two-lever procedure. For four of the subjects, the probability of receiving reinforcement after switch responses was proportional to IRT duration. For five of the subjects, these reinforcement probabilities were inversely proportional to IRT duration. Regardless, all of our subjects learned to emit IRT-mediated switching behavior that matched the reinforcement contingencies. Together, Experiments 1 and 2 provide the first evidence of which we are aware that IRTs can come to control sequential choice behavior in mice. [ABSTRACT FROM AUTHOR]

The present study demonstrates the contribution of spatial contiguity in the formation of associations between two neutral stimuli. Using human participants, we used visual conditioned stimuli (CSs) in a sensory preconditioning design in which simultaneous CS2-CS1 pairings and CS4-CS3 pairings were interspersed during Phase 1, followed by sequential CS1-US+ (i.e., CS1-pleasant US) and CS3-US- − (i.e., CS3-unpleasant US) pairings during Phase 2. The conditioned response was a shift in the gaze of the participants to the location where the US+ (i.e., short video clip) appeared. Distances between CS2 and CS1 and between CS4 and CS3 were manipulated. Our results showed a greater response to CS2 when the Phase 1 stimuli were adjacent rather than separated by 100 pixels. Implications for the role of spatial contiguity in associative learning are discussed. [ABSTRACT FROM AUTHOR]

Operant behavior appears to be organized in bouts of responses, whose parameters are differentially sensitive to various manipulations. This study investigated potential differential effects of three forms of operant response disruption—extinction (EXT), non-contingent reinforcement (NCR), and prefeeding (PRE)—on response bouts. In Experiment 1, Wistar Kyoto rats (WKY) were trained on a tandem variable-time (VT) 120 s fixed-ratio (FR) 5 schedule of reinforcement; after stability was established, their responding was disrupted for three sessions with one of the three disrupters (EXT, NCR, or PRE). In Experiment 2, Long Evans (LE) rats were trained on a tandem VT 240 s FR 5 to stability, and their responding disrupted with EXT or NCR. In EXT and NCR, response rates declined significantly and progressively over the course of the session, primarily due to a declining bout-initiation rate in EXT, and to fewer responses per bout in NCR. In contrast, a session-wide drop in response rate was observed in PRE, primarily due to a reduction in bout-initiation rate at the start of the session. These findings suggest that each form of disruption differentially impacts dissociable aspects of behavior. Theories of behavioral persistence should account for these functional relations, which appear to be obscured in response rate measures. [ABSTRACT FROM AUTHOR]

Resurgence is typically defined as an increase in a previously extinguished target behavior when a more recently reinforced alternative behavior is later extinguished. Some treatments of the phenomenon have suggested that it might also extend to circumstances where either the historic or more recently reinforced behavior is reduced by other non-extinction related means (e.g., punishment, decreases in reinforcement rate, satiation, etc.). Here we present a theory of resurgence suggesting that the phenomenon results from the same basic processes governing choice. In its most general form, the theory suggests that resurgence results from changes in the allocation of target behavior driven by changes in the values of the target and alternative options across time. Specifically, resurgence occurs when there is an increase in the relative value of an historically effective target option as a result of a subsequent devaluation of a more recently effective alternative option. We develop a more specific quantitative model of how extinction of the target and alternative responses in a typical resurgence paradigm might produce such changes in relative value across time using a temporal weighting rule. The example model does a good job in accounting for the effects of reinforcement rate and related manipulations on resurgence in simple schedules where Behavioral Momentum Theory has failed. We also discuss how the general theory might be extended to other parameters of reinforcement (e.g., magnitude, quality), other means to suppress target or alternative behavior (e.g., satiation, punishment, differential reinforcement of other behavior), and other factors (e.g., non- contingent versus contingent alternative reinforcement, serial alternative reinforcement, and multiple schedules). [ABSTRACT FROM AUTHOR]

Pavlovian conditioning is sensitive to the temporal relationship between the conditioned stimulus (CS) and the unconditioned stimulus (US). This has motivated models that describe learning as a process that continuously updates associative strength during the trial or specifically encodes the CS–US interval. These models predict that extinction of responding is also continuous, such that response loss is proportional to the cumulative duration of exposure to the CS without the US. We review evidence showing that this prediction is incorrect, and that extinction is trial-based rather than time-based. We also present two experiments that test the importance of trials versus time on the Partial Reinforcement Extinction Effect (PREE), in which responding extinguishes more slowly for a CS that was inconsistently reinforced with the US than for a consistently reinforced one. We show that increasing the number of extinction trials of the partially reinforced CS, relative to the consistently reinforced CS, overcomes the PREE. However, increasing the duration of extinction trials by the same amount does not overcome the PREE. We conclude that animals learn about the likelihood of the US per trial during conditioning, and learn trial-by-trial about the absence of the US during extinction. Moreover, what they learn about the likelihood of the US during conditioning affects how sensitive they are to the absence of the US during extinction. [ABSTRACT FROM AUTHOR]

Historically, there has been considerable interest in a large variety of forms of associative interference. However, various factors including interest in clinical application and perhaps recent funding priorities have resulted in a narrowed focus on one particular instance of interference, extinction, with relative neglect of other types of interference. We have been using the existing literature and conducting new experiments to determine whether there is a consistent set of rules governing the occurrence and persistence of two-phase associative interference across (a) proactive and retroactive interference, (b) cue and outcome interference, (c) the type of training in phase 1 (excitatory, inhibitory, or simple nonreinforcement), and (d) the type of training in phase 2 (excitatory, inhibitory, or simple nonreinforcement). Our hope is that a return to more general questions concerning associative interference might reveal broad truths concerning the nature of forgetting. Identifying global principles of associative interference may also help us better appreciate the nature of extinction, including how it can be enhanced and made more enduring, as well as how it can be minimized and made more fleeting. [ABSTRACT FROM AUTHOR]

Two experiments with rats examined relapse of an operant behavior that occurred after the behavior was suppressed by reinforcing (incentivizing) an alternative behavior. In the first phase, a target response (R1) was reinforced. In a treatment phase, R1 was still reinforced, but a new response (R2) was introduced and associated with a larger reinforcer. As in human contingency management treatments, incentivizing R2 this way was effective at suppressing R1. However, when R2’s reinforcement was discontinued, there was a robust and immediate relapse to R1. Experiment 1 found that the strength of R1 during relapse testing was not different from that seen in a no treatment control. Experiment 2 found that relapse could nevertheless be reduced by presenting reinforcers not contingent on responding during the test. Either the reinforcer for R1 or the reinforcer for R2 (which were qualitatively different types of food pellets) were effective. The experiments introduce a laboratory method for studying relapse and how to prevent it after contingency management treatments, and suggest at least one treatment that discourages relapse. The incentivized choice paradigm differs from other models of relapse of operant behavior (e.g., resurgence, renewal, reinstatement) in that it does not focus on the return of behaviors that are inhibited by extinction. [ABSTRACT FROM AUTHOR]

A review of different investigators’ definitions of resurgence revealed several common features: First, characteristics of the resurgent, or target, response, such as its transience; magnitude; time course within and across sessions; and relativity to a baseline response rate are not mentioned. Second, the target response is described as being established through its reinforcement in the first, or Training, phase of a resurgence procedure. Third, the target response must be eliminated as an alternative response is reinforced in the second, Alternative Reinforcement, phase of a resurgence procedure. Fourth, the alternative response must be extinguished during the Resurgence Test phase. Fifth, none of the definitions allude to any contribution of stimulus variables to resurgence. When reconsidered in light of contemporary research germane to these features, none of the reviewed definitions sufficiently reflect important variables in the generation and assessment of resurgence. The review concludes with a proposed working definition that takes into account contemporary research involving all of the aforementioned factors. [ABSTRACT FROM AUTHOR]

Following training with verbal stimulus relations involving A is greater than B and B is greater than C, verbally-competent individuals reliably select A > C when asked “which is greater, A or C?” (i.e., verbal transitive inference). This result is easy to interpret. Nonhuman animals and humans with and without intellectual disabilities have been exposed to nonverbal transitive-inference procedures involving trained arbitrary stimulus relations. Following the training of A + B-, B + C-, C + D-, and D + E-, B reliably is selected over D (i.e., nonverbal transitive inference). Such findings are more challenging to interpret. The present research explored accounts of nonverbal transitive inference based in transitive inference per se, reinforcement, such as value-transfer theory, and operant stimulus control. In Experiment 1, college students selected B > G following the training of A + B-, B + C-, C + D-///E + F-, F + G-, and G + H- (where///signifies the omission of D + E-). In Experiment 2, college students selected B > G following the training of A + B-, B + C-, C + D-///E + F-, F + G-, and G + X- (where X refers to 10 stimuli that alternated across trials). In Experiment 3, college students selected G > B following the training of Y + B-, B + C-, C + D-///E + F-, F + G-, and G + X- (where Y and X refer to 10 stimuli, respectively, that alternated across trials). These findings are discussed in the context of operant stimulus control by offering an approach based in stimulus B typically acquiring only a select stimulus control topography. [ABSTRACT FROM AUTHOR]

Rats were trained under a discrete-trials adjusting-magnitude schedule in which a response on lever A delivered either a larger or a smaller reinforcer ( q A1 and q A2 ) with equal probability, while a response on B delivered a reinforcer whose size q B was adjusted according to the rats’ choices. When A was preferred in a given block of trials, q B was increased in the following block; when B was preferred, q B was reduced in the following block. The oscillating changes in q B , analysed by the Fourier transform, could be described by a power spectrum with a dominant period of about 50 trial blocks. With q A1 held constant, the equilibrium value of q B ( q B(50) ) was monotonically related to q A2 , and exceeded the arithmetic mean of q A1 and q A2 when q A1 was substantially greater than q A2 . A model derived from the multiplicative model of intertemporal choice provided a post hoc description of the data. Simulation of block-by-block changes in q B derived from the model were generally consistent with the experimental data. Implications of the results for models of risky choice and for future use of the schedule in neurobehavioural experiments are discussed. [ABSTRACT FROM AUTHOR]

The effect of lever height on the temporal organization of reinforced lever pressing was examined. Lever pressing was reinforced on a variable-interval 30-s schedule in rats, with lever height manipulated across six successive conditions. Parameters of the organization of responses in bouts (bout length distribution, bout-initiation rate, within-bout rate, and sequential dependency) were estimated. These estimates revealed (1) a qualitative change in the distribution of IRTs and their sequential dependency when the lever was too high, (2) a mixture of geometrically-distributed bout lengths at all lever heights, and (3) longer bouts at lower and intermediate lever heights. In accordance with previous data, these findings suggest that lower and intermediate lever heights favored lever pressing with longer bout lengths, faster bout initiation, faster within-bout responding, and more sequentially dependent timing. These results underscore the disociability of motoric capacity in operant performance, and may reflect the influence of the body size on the temporal organization of the operant. [ABSTRACT FROM AUTHOR]

Greater rates of intermittent reinforcement in the presence of discriminative stimuli generally produce greater resistance to extinction, consistent with predictions of behavioral momentum theory. Other studies reveal more rapid extinction with higher rates of reinforcers – the partial reinforcement extinction effect. Further, repeated extinction often produces more rapid decreases in operant responding due to learning a discrimination between training and extinction contingencies. The present study examined extinction repeatedly with training with different rates of intermittent reinforcement in a multiple schedule. We assessed whether repeated extinction would reverse the pattern of greater resistance to extinction with greater reinforcer rates. Counter to this prediction, resistance to extinction was consistently greater across twelve assessments of training followed by six successive sessions of extinction. Moreover, patterns of responding during extinction resembled those observed during satiation tests, which should not alter discrimination processes with repeated testing. These findings join others suggesting operant responding in extinction can be durable across repeated tests. [ABSTRACT FROM AUTHOR]

The systematic anticipation and preservation errors produced by pigeons around the reversal point in midsession reversal (MSR) learning experiments suggest that an internal time estimation cue, instead of a more efficient external cue provided by reinforcement, controls behavior over the course of a session. The current experiments examined the role and effectiveness of other external cues in the MSR task. In Experiment 1, providing differential outcomes based on response key location produced fewer errors prior to, but not after, the reversal as compared with a non-differential outcomes condition. Experiment 2a used alternating differentially colored ITIs ( cued sessions) or dark ITIs ( un-cued sessions ) during each half of the session. The ITI cues improved switch efficiency both prior to and after the reversal. Experiment 2b introduced probe trials around the reversal, testing ITI color cues added to un-cued sessions or removed from cued sessions. Results showed control by the ITI cues when they were available and control by the time-based cue when they were unavailable. This suggests both cues were being simultaneously processed when available and that the cues could also independently provide sufficient information about future reinforcement. In Experiment 2c, ITI cues were inserted as probe trials in the opposite half of the session ( miscues ). The closer such miscue trials were to the reversal, the more the ITI cues exerted control over behavior. Together, these results indicate that as the utility of internal temporal cues is reduced, the use of external visual cues increases. These results have implications for the way in which cues dynamically shift in controlling behavior over time based on their relative rates of utility, and are discussed in light of an occasion setting perspective. [ABSTRACT FROM AUTHOR]

In an operant serial feature-positive procedure, an occasion setter (OS X ) signals that a response will be reinforced in the presence of a second stimulus (e.g., a discriminative stimulus, A). During a transfer test, the OS is paired with a different discriminative stimulus. Experiment 1a tested transfer effects in a touchscreen-based spatial occasion setting task with pigeons. During training, four OSs (OS W , OS X , OS Y , and OS Z ) were paired on separate trials with landmark A (LM A ) or B (LM B ) and the opportunity for a reinforced response at one location to the immediate left (R 1 ) or right (R 2 ) of the LM (OS W → LM A :R 1 , OS X → LM A :R 2 , OS Y → LM B :R 1 , OS Z → LM B :R 2 ). Training also included non-reinforced trials of LM A and LM B alone (LM A - and LM B -) and trials of a non-modulated LM with R 1 and R 2 reinforced across separate trials (LM C :R 1 and LM C :R 2 ). After training, the number and spatial location of responses during test trials of a LM paired with the same OS as in training did not differ reliably from transfer tests of an OS paired with a different, modulated LM (OS W → LM B and OS Y → LM A ), but did differ from transfer to the non-modulated LM (OS X → LM C ). Experiment 1b utilized the same pigeons and training with LM B to test the degree to which the spatial stability of a LM influenced transfer. Retraining with LM A was intended to establish it as a non-modulated, stable LM (LM A :R 2 ). Subsequent tests with LM A revealed reduced modulation by the formerly trained OS (OS W ), and complete disruption of modulation of spatial location during transfer with a different OS (OS Y ). These findings further our understanding of the conditions under which OSs may develop and transfer modulation. [ABSTRACT FROM AUTHOR]

An occasion setter is a stimulus that modulates the ability of another stimulus to control behavior. A rich history of experimental investigation has identified several important properties that define occasion setters and the conditions that give rise to occasion setting. In this paper, we first consider the basic hallmarks of occasion setting in Pavlovian conditioning. We then review research that has examined the mechanisms underlying the crucial role of context in Pavlovian and instrumental extinction. In Pavlovian extinction, evidence suggests that the extinction context can function as a negative occasion setter whose role is to disambiguate the current meaning of the conditioned stimulus; the conditioning context can also function as a positive occasion setter. In operant extinction, in contrast, the extinction context may directly inhibit the response, and the conditioning context can directly excite it. We outline and discuss the key results supporting these distinctions. [ABSTRACT FROM AUTHOR]

In two experiments, using an online conditioned suppression task, we investigated the possibility of reinstatement of extinguished feature-target compound presentations after sequential feature-positive discrimination training in humans. Furthermore, given a hierarchical account of Pavlovian modulation (e.g., Bonardi, 1998; Bonardi and Jennings, 2009 ), we predicted A-US reinstatement to be stronger than US-only reinstatement. In Experiment 1, participants learned a sequential feature-positive discrimination (X → A + |A − ), which was subsequently extinguished (X → A − ). During the following reinstatement phase, group US-only received US-only presentations (not signalled), group A-US received A-US presentations, and the Control group received exposure to the context, but no CSs or USs, for an equal amount of time. Reinstatement of differential X → A/A responding was observed in the US-only group but not in the Control or A-US groups. Although differential X → A/A responding was not significant in group A-US, responding to the X → A compound was significantly stronger compared to that in group US-only. Hence, it could be the case the group A-US showed stronger reinstatement, but that differential responding was abolished due to excitation gained by A. Experiment 2 was set up to circumvent the acquired excitation of A by testing transfer of the feature after A-US reinstatement to a different target, B. Participants acquired two discriminations, X → A/A and Y → B/B, of which X → A was then extinguished. Subsequently, group A-US received reinforced presentations of A during a reinstatement phase while group Control received exposure to the context. Final testing of the novel X → B compound was hypothesized to show higher responding in group A-US than in group Control, but findings of this approach were limited due to acquired equivalence and/or perceptual factors causing a secondary extinction effect. We conclude to have obtained clear evidence in favour of reinstatement of differential responding after human Feature-Positive discrimination training and subsequent compound extinction, but no evidence in favour of A-US presentations being a stronger trigger for reinstatement than are US-only presentations. [ABSTRACT FROM AUTHOR]

The available data on occasion setting led Susan Brandon and Allan Wagner (Brandon and Wagner, 1998; Wagner and Brandon, 2001) to formulate what has come to be known as a replaced-elements conception (REM) of context-dependent cues within the SOP model (Wagner, 1981). In the present paper, we review the development of the theory, and show how, with a few congenial assumptions about shared cues, it can address some of the major regularities concerning when the transfer of occasion setting does or does not occur. Among the particular examples are the relatively unique transfers that have been reported to occur between separate serial discriminations and between targets that have been trained with the same versus different reinforcers. [ABSTRACT FROM AUTHOR]

Since occasion setting was identified as a type of learning independent of ‘simple’ associative processes, a great deal of research has explored how occasion setters are established and operate. Initial theories suggested that they exert hierarchical control over a target CS → US association, facilitating the ease with which a CS can activate the US representation and elicit the CR. Later approaches proposed that occasion setting arises from an association between a configural cue, formed from the conjunction of the occasion setter and CS, and the US. The former solution requires the associative principles dictating how stimuli interact to be modified, while the latter does not. The history of this theoretical distinction, and evidence relating to it, will be briefly reviewed and some novel data presented. In summary, although the contribution of configural processes to learning phenomena is not in doubt, configural theories must make many assumptions to accommodate the existing data, and there are certain classes of evidence that they are logically unable to explain. Our contention is therefore that some kind of hierarchical process is required to explain occasion-setting effects. [ABSTRACT FROM AUTHOR]

Three experiments explored the utility of considering mechanisms of occasion setting for understanding patterning and biconditional discriminations – two more complex conditional discriminations in which the stimulus-outcome relations of occasion setting are embedded. In Experiment 1, rats were trained in an appetitive conditioning task with either a biconditional or a patterning discrimination using relatively brief CSs (10 s) and differential outcomes as USs. In this study, rats learned the positive patterning task before they had learned negative patterning, and the biconditional task was the most difficult. However, a detailed examination of the results suggested that rats trained in the biconditional task responded to the stimulus compounds mainly on the basis of individual stimulus-outcome associations. Different conditioned response (CR) topographies as a function of reinforcer type complicated interpretation of these results. Experiment 2 confirmed that the biconditional task, with the parameters used here, was not learned, regardless of whether training involved differential or non-differential outcomes. In Experiment 3 the CS duration was increased to 30 s and two different USs were used that each supported similar CR topographies. Under these conditions, we observed that whereas the positive patterning task was learned most rapidly, the biconditional discrimination was learned faster than the negative patterning task. Considered in relation to other findings on patterning and biconditional discriminations, the results suggest that elemental, configural, and/or modulatory occasion setting mechanisms may play different roles in these complex conditional discrimination tasks especially as a function of stimulus duration and differential outcome training. [ABSTRACT FROM AUTHOR]

Prior findings indicate that adolescent rats exhibit difficulty using negative occasion setters to guide behavior compared to adult rats (Meyer and Bucci, 2014). Here, additional groups of juvenile rats were trained in the same negative occasion setting procedure to further define the development of negative occasion setting. Beginning on either postnatal day (PND) 30, 40, or 50, rats received daily training sessions in which a tone was paired with food reinforcement on some trials, while on other trials a light preceded the tone and no reinforcement was delivered. We found that rats that began training on PND 50 required 10 training sessions to discriminate between the two types of trials, consistent with prior findings with young adult rats. Interestingly, rats in the PND 30 group (pre-adolescents) also required just 10 training sessions, in stark contrast to adolescent rats that began training on PND 35 (adolescents) and required 18 sessions (Meyer and Bucci, 2014). Rats that began training on PND 40 (adolescents) also required more sessions than the PND 30 group. These data indicate that the development of negative occasion setting is non-linear and have direct bearing on understanding the behavioral and neural substrates that underlie suboptimal behavioral control in adolescents. [ABSTRACT FROM AUTHOR]

Sexual partner preferences can be strengthened, weakened or even drastically modified via Pavlovian conditioning. For example, conditioned same-sex partner preference develops in sexually-naïve male rats that undergo same-sex cohabitation under the effects of quinpirole (QNP, D2 agonist). Here, we assessed the effect of prior heterosexual experience on the probability to develop a conditioned same-sex preference. Naïve or Sexually-experienced males received either Saline or QNP and cohabited during 24 h with a male partner that bore almond scent on the back as conditioned stimulus. This was repeated every 4 days for a total of three trials and resulted in four groups (Saline-naïve, Saline-experienced, QNP-naïve, QNP-experienced). Social and sexual preference were assessed four days after the last conditioning trial in a drug-free test in which experimental males chose between the scented familiar male and a novel sexually receptive female. Results showed that Saline-naïve, Saline-experienced and QNP-experienced displayed a clear preference for the female (opposite-sex). By contrast, only QNP-naïve males displayed a same-sex preference. Accordingly, QNP-experienced males were not affected by the conditioning process and continued to prefer females. We discuss the effects of copulation and D2 agonists on the facilitation and/or disruption of conditioned partner preferences [ABSTRACT FROM AUTHOR]

The spontaneously hypertensive (SHR/NCrl) rat from Charles River is one of the most widely used models of the combined subtype of Attention-Deficit/Hyperactivity Disorder (ADHD-C). Although often used as its control strain, the Wistar Kyoto (WKY/NCrl) from Charles River has been proposed as a model of the predominately inattentive subtype of ADHD (ADHD-PI). In Experiment 1 SHR/NCrl, WKY/NCrl, and Wistar (WI; the progenitor strain for the two models) rats were trained on a left → right lever-press sequence in the presence of light discriminative stimuli that signaled the active lever in the sequence. In subsequent conditions the discriminative light cues were removed or reversed. WKY/NCrl accuracy remained relatively stable across cue light transitions. SHR/NCrl and WI accuracy was more disrupted when light cues were removed or reversed—an indication that behavior of the WKY/NCrl rats may not have come under control of the discriminative light cues as it did for the other strains, but relied more on past behavior and spatial cues. In Experiment 2, all three strains were exposed to a response-initiated fixed-interval (RIFI) 8-s schedule of reinforcement. In RIFI schedules behavior must be timed from a past instance of the target response. Replicating previous work, timing during the FI was roughly equivalent across the three strains; however, latencies to initiate the FI were significantly longer for SHR/NCrl than WKY/NCrl and WI rats, suggesting SHR/NCrl behavior was less sensitive to the first-response:food contingency in the RIFI schedule. These findings identify differences in stimulus control between the three strains and may help determine the efficacy of SHR/NCrl and WKY/NCrl as models of ADHD subtypes in humans. [ABSTRACT FROM AUTHOR]

When given a choice between an alternative with a low probability of reinforcement and discriminative stimuli, and another with a higher probability of reinforcement and non-discriminative stimuli, pigeons show a clear preference for the former but rats clearly prefer the later. It has been reported that pigeon’s suboptimal choice is associated to a diminishing effect of the stimulus correlated with non-reinforcement. In the present paper, we explored the possibility that rats' optimal choice is more strongly influenced than pigeons' by the stimulus associated to non-reinforcement and that the effects of it do not dissipate during training. We trained rats to choose between an alternative with 0.50 probability of reinforcement and discriminative stimuli, and an alternative with 0.75 probability of reinforcement and non-discriminative stimuli. We replicated the strong preference for the optimal alternative. Then, after several sessions of training, we presented summation trials in which both the stimulus associated to reinforcement and the stimulus associated to non-reinforcement were simultaneously presented. The results showed that the stimulus associated to non-reinforcement exerted a strong effect on choice, and, more importantly, that it did not seem to dissipate across training. These results suggest that the strong difference found between pigeons and rats in the suboptimal choice procedure is potentially related to differences in the impact of conditioned inhibitors. [ABSTRACT FROM AUTHOR]

An article published in Behavioural Processes ( Calvin and McDowell, 2015 ) contemplated that the approach to neural networks developed by the present authors cannot simulate certain behavioral findings, notably the Kamin blocking effect and successive conditioning. Here we demonstrate that these concerns are unwarranted as an overall characterization of the approach. In addition, several other more general issues identified in the target article are addressed as well. These include the determination of network architectures, the assignment-of-credit problem, the potential for catastrophic interference, and the falsifiability of the model. [ABSTRACT FROM AUTHOR]

Retrospective revaluation refers to an increase (or decrease) in responding to conditioned stimulus (CS X) as a result of decreasing (or increasing) the associative strength of another CS (A) with respect to the unconditioned stimulus (i.e., A-US) that was previously trained in compound with the target CS (e.g., AX–US or just AX). We discuss the conditions under which retrospective revaluation phenomena are most apt to be observed and their implications for various models of learning that are able to account for retrospective revaluation (e.g., Dickinson and Burke, 1996; Miller and Matzel, 1988; Van Hamme and Wasserman, 1994 ). Although retroactive revaluation is relatively parameter specific, it is seen to be a reliable phenomenon observed across many tasks and species. As it is not anticipated by many conventional models of learning (e.g., Rescorla and Wagner, 1972 ), it serves as a critical benchmark for evaluating traditional and newer models. [ABSTRACT FROM AUTHOR]

Resurgence occurs when a previously reinforced and then extinguished target response increases due to a worsening of reinforcement conditions for an alternative response. We conducted four crowdsourcing experiments to evaluate effects of alternative-reinforcer rate and magnitude on resurgence with humans. Contingent on an alternative response, we manipulated across groups either the rate of point delivery (Experiment 1) or number of points delivered per reinforcer (Experiments 2–3). Experiment 4 arranged combinations of high- or low-rate and high- or low-magnitude alternative reinforcement across four groups. When extinguishing alternative responding across experiments, we observed resurgence of target responding with relatively high rates of alternative reinforcement but differences in reinforcer magnitude did not influence resurgence. A quantitative model based on the concatenated matching law, Resurgence as Choice in Context (RaC2), provided a poor fit to the data, generally underpredicted target responding, and could not account for data from control groups experiencing extinction of target responding in the absence of alternative reinforcement. We then fit a modified version of RaC2 borrowing an assumption from theories of choice that suggest some proportion of reinforcers are misallocated between responses – this modified version of RaC2 provided a better account of these findings. • Examined effects of reinforcer rate and magnitude on resurgence through crowdsourcing. • In four experiments, greater reinforcer rates but not magnitudes increased resurgence. • We fit a quantitative model based on matching, Resurgence as Choice in Context (RaC2). • RaC2 fits improved when assuming reinforcers are misallocated between responses. • Misallocation also allowed RaC2 to be fit for the first time to simple extinction data. [ABSTRACT FROM AUTHOR]

Previously extinguished operant responding recurs under both resurgence and renewal procedures, but the effects of combining these procedures on recurrence has not been studied. Because renewal and resurgence are known to independently produce response recurrence, we examined whether greater resurgence would occur if the resurgence procedure was combined with an ABA renewal procedure, relative to a resurgence procedure without contextual changes. Three pigeons were exposed to a concurrent resurgence procedure in which key colors served as contextual stimuli. In the Training phase, reinforcement for pecking two keys was scheduled on concurrent variable-interval (VI) 120-s VI 120-s schedules, each correlated with different key colors. In the Alternative Reinforcement phase, reinforcement occurred when neither key was pecked for 20-s (a differential-reinforcement-of-other-behavior [DRO] 20-s schedule). During this phase, one of the key colors was changed (ABA key), while the other key color remained as in the Training phase (AAA key). In the third phase, reinforcement was not provided and the color of the ABA key was changed back to the color in effect during the Training phase while the same color remained in effect on the other key. Greater resurgence occurred on the ABA renewal key with each pigeon, demonstrating that a superimposed ABA renewal procedure increases resurgence. [ABSTRACT FROM AUTHOR]

Experimentally naïve rats acquired lever pressing with delayed reinforcement when the immediate programmed consequence for lever pressing was the simultaneous retraction of two identical levers. Presses on one lever also produced access to sweetened condensed milk after a delay of 10 s following retraction. Presses on the second lever resulted in retraction only. Lever retraction prevented the possibility of adventitious reinforcement of contacting the operanda during the reinforcement delays. Several measures indicated that the delayed reinforcers strengthened behavior. The majority of responses for all rats were on the lever that initiated reinforcer delivery. Responding for seven out of eight rats decreased during a subsequent extinction phase in which retraction was the only consequence arranged for lever pressing. Responding recovered rapidly when food reinforcement was available again. Furthermore, when contingencies on the two levers were switched, rats allocated their behavior accordingly, showing control by the delayed reinforcers. [ABSTRACT FROM AUTHOR]

There is a vast literature on the behavioural effects of partial reinforcement in Pavlovian conditioning. Compared with animals receiving continuous reinforcement, partially rewarded animals typically show (a) a slower development of the conditioned response (CR) early in training and (b) a higher asymptotic level of the CR later in training. This phenomenon is known as the partial reinforcement acquisition effect (PRAE). Learning models of Pavlovian conditioning fail to account for it. In accordance with the incentive salience hypothesis, it is here argued that incentive motivation (or ‘wanting’) plays a more direct role in controlling behaviour than does learning, and reward uncertainty is shown to have an excitatory effect on incentive motivation. The psychological origin of that effect is discussed and a computational model integrating this new interpretation is developed. Many features of CRs under partial reinforcement emerge from this model. [ABSTRACT FROM AUTHOR]

Highly palatible foods may induce addiction-related behaviors. However, this has yet to be established in non-human primates. Therefore, we evaluated whether marmoset monkeys ( Calllithrix penicillata ) acquire a conditioned-place-preference (CPP) for chocolate and if this response is detectable after a 24-h and 15-day period. Subjects were first habituated to a two-compartment CPP box and then randomly assigned to a chocolate or control group. Thereafter, they were given access to only one compartment during daily 15-min conditionings, held on six consecutive days. On each trial, the chocolate group received pieces of chocolate (50 g) in this context, whereas controls were not given a food reward. Marmosets were subsequently tested for preferring this (food) paired context after a 24-h and 15-day interval. During conditioning, individual foraging and the amount of chocolate ingested by each pair of the chocolate group remained constant. However, compared to pre-CPP levels, the time spent inside/in contact with the conditioned compartment increased significantly, while the latency to first entry decreased on both post-CPP intervals. For controls, the parameters remained unaltered. Thus, chocolate induced a persistent CPP response—an aspect usually associated with drug-related rewards. [ABSTRACT FROM AUTHOR]

Gold-standard psychological treatments such as exposure therapy are significantly undermined by high relapse rates. Although exposure-based treatments are capable of extinguishing maladaptive behaviours, these behaviours often spontaneously re-emerge over time – a phenomenon known in experimental research as spontaneous recovery. Understanding the factors that underlie this process is essential to improving long-term treatment outcomes. One factor that is yet to be properly examined is the effect of the total span of time across which behaviours are learned. To date, only one study by Gallistel & Papachristos (2020) has explored this in mice. Their findings suggest that long spans of acquisition learning result in greater spontaneous recovery compared to short spans. We investigated the effect of conditioning span across 5 experiments using rats. Contrary to Gallistel & Papachristos, our results found no difference in recovery between rats conditioned over a long span versus a short span, following short, intermediate and long delay intervals. This suggests that the span of conditioning does not affect the magnitude of recovery, nor the rate at which recovery emerges. Unexpectedly, conditioning span did appear to influence the strength of responding during acquisition, such that longer conditioning spans led to higher levels of responding. This finding could indicate that the learning process operates over a long time period beyond the original training episode. However, further research is needed to establish whether conditioning span influences the strength of what is learned, or instead the performance of a conditioned response. • Conditioned responses can spontaneously recover after extinction, a phenomenon likened to relapse after exposure therapy. • Our study pursued recent evidence that the timespan across which behaviours are learned can affect spontaneous recovery. • We found that conditioning span did not affect the size of recovery or how quickly responding re-emerged after extinction. • Span did affect the amount of responding acquired, suggesting the learning process extends beyond the conditioning session. [ABSTRACT FROM AUTHOR]

Resurgence occurs when a worsening of conditions for an alternative response (e.g., extinction) increases a previously reinforced and subsequently extinguished target response. In contrast, renewal is an increase in a response previously eliminated by extinction following a contextual change. Moreover, arranging contextual changes during resurgence tests has enhanced relapse compared with the absence of contextual changes. Several laboratory studies evaluating resurgence in humans have included interruptions of operant tasks by presenting instructions or "blackouts" immediately prior to phase changes in which reinforcement contingencies change. Such interruptions could enhance relapse during testing similarly to changes in contextual stimuli. We tested this possibility in the present study with human participants recruited via Amazon Mechanical Turk by interrupting the task across groups with 1-s blackouts every 12 s, 60 s, between phases, or by arranging no blackouts in a control group. We found that blackouts prior to phase changes increased resurgence effects relative to no blackouts, suggesting that blackouts between phases are a type of contextual manipulation serving to increase the salience of contingency changes. • Evaluated whether blackouts serve as contextual stimuli to enhance resurgence. • Brief blackouts between phase changes increased resurgence compared to no blackouts. • Between-phase blackouts could increase salience of contingency changes. [ABSTRACT FROM AUTHOR]

In human learning a distinction has been made between implicit and explicit learning. Implicit learning is thought involve automatic processes of the kind involved in Pavlovian conditioning, while explicit learning is thought to involve conscious hypothesis testing and rule formation, in which the ability to report the rule used to learn the task is taken as evidence. Because non-verbal animals cannot provide such evidence, several indirect methods have been proposed. One of these methods is faster learning by humans of certain explicitly learned tasks than implicitly learned tasks, but pigeons do not show a similar difference. Another method involves the 1-back-reinforcement conditional discrimination (if A choose X, if B choose Y) in which feedback following the conditional response is delayed until the next trial. It has been argued that implicit learning cannot occur over the delay between the conditional response and the reinforcer on the next trial, yet, it has been found that monkeys can learn this 1-back reinforcement task. We have argued that such learning can occur implicitly. We have found that pigeons, a species not thought to learn explicitly, can show significant learning of both 1-back reinforcement matching and 1-back reinforcement mismatching, two versions of the 1-back-reinforcement conditional discrimination. We propose that the evidence for explicit learning by non-verbal animals suffers from alternative simpler accounts because the rationale for explicit learning is based on assumptions that likely are not correct. • It is assumed that implicit learning cannot occur over delays of a few seconds. • In the 1-back matching task reinforcement is provided on the following trial. • It is assumed that pigeons learn implicitly. • Yet they show evidence of learning 1-back matching and mismatching. • Conclusion: Implicit learning can occur with delayed reinforcement. [ABSTRACT FROM AUTHOR]

Highlights: [•] Interval timing with intrudes results in a wide range of behavioral responses such as, run (ignore the intruder), stop (retain the state of the clock and restart after intruder), and reset. [•] The striatal beat frequency (SBF) is a simple, neurobiologically inspired, computational model that produces both precise and time-scale invariant interval timing and can explain the intruders’ effects. [•] A reset is implemented in SBF model by a strong hyperpolarization of neural oscillators followed by a rapid postinhibitory rebound. [•] The SBF model explains the over-reset induced by fear-evoking distracters assuming a strong inhibition (similar to reset) with a duration approximately gauged by the relaxation time constant associated to the long-lasting behavioral freeze. [•] The effect of dopamine/norepinephrine reuptake inhibitor nomifensine was modeled by speeding-up the oscillators of the SBF mode which produced an advance of the peak response similar to the experimental data. [ABSTRACT FROM AUTHOR]

Highlights: [•] Amygdala is a critical brain area for Pavlovian conditioning. [•] There are amygdalar correlates of detection of prediction error. [•] There are amygdalar correlates of temporal expectancy. [•] The potential role of the amygdala in processing timing is not yet studied. [•] We suggest new specific strategies to reveal the role of the amygdala in timing. [ABSTRACT FROM AUTHOR]

Abstract: An early finding in the behavioral analysis of learning was that conditioned responding weakens as the conditioned stimulus (CS) and unconditioned stimulus (US) are separated in time. This “trace” conditioning effect has been the focus of years of research in associative learning. Theoretical accounts of trace conditioning have focused on mechanisms that allow associative learning to occur across long intervals between the CS and US. These accounts have emphasized degraded contingency effects, timing mechanisms, and inhibitory learning. More recently, study of the neurobiology of trace conditioning has shown that even a short interval between the CS and US alters the circuitry recruited for learning. Here, we review some of the theoretical and neurobiological mechanisms underlying trace conditioning with an emphasis on recent studies of trace fear conditioning. Findings across many studies have implications not just for how we think about time and conditioning, but also for how we conceptualize fear conditioning in general, suggesting that circuitry beyond the usual suspects needs to be incorporated into current thinking about fear, learning, and anxiety. [Copyright &y& Elsevier]