Sleep may facilitate preferential selection and reactivation of emotional information for memory consolidation, contributing to negative overgeneralization (i.e., an increased tendency to generalize negative information) in anxious individuals. We examined two aspects of emotional memory-recognition and generalization-in peri-adolescents across a spectrum of anxiety severity using a sleep-wake design. We hypothesized that anxiety severity would interact with sleep to increase recognition and generalization of negative stimuli. Thirty-four participants (16 females; mean age = 11.4, SD = 2.0) completed an emotional memory similarity task with a 10- to 12-h sleep or wake retention interval, monitored by actigraphy and daily diary. Participants rated the valence (negative, neutral, positive) of images at encoding. During a recognition test, they identified targets (previously seen images), lures (images similar to targets), and foils (new images). A mixed-effects model showed a significant three-way interaction between anxiety severity (PARS-6), valence, and group (b = .011, SE = .005, p = .042). For negative valence, the effect of anxiety was significant in the sleep group (b = .013, p < .001) but not in the wake group (b = .0004, p = .927), with the slopes differing significantly (b = -.013, p = .020). In the sleep group, the negative slope was significantly greater than neutral (b = -.012, p = .002) but not positive (b = .007, p = .128). Slopes for neutral valence were not significant in either group (all ps > .05). Target recognition and lure discrimination interaction models were not significant. We provide evidence that anxiety severity in peri-adolescents is associated with greater generalization of emotional-particularly negative-content following sleep compared to wakefulness. Sleep-related emotional memory consolidation may contribute to negative overgeneralization, an etiological feature of anxiety disorders and a potential mechanism of change. Further investigation is warranted, especially during sensitive developmental periods like peri-adolescence.

Placebo and nocebo effects are beneficial or adverse treatment outcomes upon administration of inert treatment components. These effects have been frequently studied on pain. It remains unclear to what extent generalisation occurs in these effects on pain and other somatic sensations. This review outlines the current knowledge on stimulus generalisation (i.e., generalisation over various stimuli) and response generalisation (i.e., generalisation over various responses) of placebo and nocebo effects on prevalent somatic sensations (i.e., pain, itch, dyspnea, nausea and fatigue). The databases PubMed, Web of Science and PsycINFO were systematically searched for peer-reviewed articles reporting on experimental studies in humans of the induction and generalisation of placebo and nocebo effects on prevalent somatic sensations. Of 2025 records identified, 23 studies were included. These studies indicated that placebo and nocebo effects can generalise over stimuli (at perceptual, categorical and treatment levels) and over responses within modalities. Most studies investigated pain; fewer studies investigated itch, dyspnea, nausea and fatigue. Generalisation effects tend to be larger when the generalisation stimuli and responses more closely resemble the initial stimulus or response. Generalisation was more likely if a combination of verbal suggestion and conditioning was employed to induce placebo or nocebo effects than if either suggestion or conditioning was employed alone. Response generalisation across modalities remains unclear. Placebo and nocebo effects can generalise over stimuli and responses. More experimental and clinical research is warranted to address carryover effects of placebo and nocebo effects. The current review provides an overview of the literature on the generalisation of placebo and nocebo effects to diverse stimuli and responses. This can ultimately benefit healthcare providers to prevent carryover effects of treatment failure and harness carryover effects of treatment success.

For many years, single-case research has functioned as a vital methodology for identifying evidence-based educational and behavioral interventions for individuals with disabilities. A particular area of single-case methodology that is critical to ensuring developed interventions contribute to meaningful learner outcomes, is generalization; specifically, the use of single-case methods to evaluate if a learner can perform an acquired behavior under novel conditions (stimulus generalization) or if the learner can perform a novel behavior as a result of acquiring a different behavior (response generalization). We reviewed decades of single-case research to identify the extent to which generalized behavior change has been included as an outcome and rigorously evaluated within the context of single-case designs. Of the 1,342 single-case publications we reviewed, approximately one third included a measure of generalization. In examining a subset of this research focusing on withdrawal, multiple baseline, and multiple probe designs, we identified 106 publications that evaluated generalization within the context of an experimental single-case framework, for which 36 publications contained designs meeting standards developed by the What Works Clearinghouse. We propose that these rigorous studies can serve as examples to advance the use of single-case methods for answering questions about generalized behavior change.

Stimulus generalization, or the transfer of learned responses between stimuli, is a critical ability for adaptation to everyday life. In a typical experiment, generalization is assessed by measuring responses to stimuli varying along a physical dimension. Variations in the gradient of learned responses are usually interpreted as differences in the underlying cognitive process of generalization. A recent study by Zaman, Yu, and Verheyen (2023) seeks to challenge this view, arguing that generalization is best modeled by perceptual factors and that individual differences in perception or ability to identify the stimuli are primary drivers of generalization. In this commentary, we outline issues in the methodology and analysis of Zaman et al.'s study and show that their key result is not robust to the addition of theoretically informed alternative models. We conclude that the evidence is not strong enough to support their conclusions regarding the primacy of perceptual processes in generalization. We propose some ways forward for researchers in this field attempting to understand the psychological mechanisms underlying individual differences in stimulus generalization. (PsycInfo Database Record (c) 2025 APA, all rights reserved).

It is widely recognized that the most effective approach to treating obsessive-compulsive disorder (OCD) combines medication with cognitive-behavioral therapy (CBT), particularly exposure and response prevention (ERP). This case sheds light on a unique and unconventional way of applying ERP in a patient with treatment-resistant and atypical OCD, ultimately proving more beneficial than medication alone. What made this case unusual was the patient’s deeply ingrained overvalued ideas, superstitions, and strong religious beliefs, which played a significant role in shaping their symptoms. Additionally, the patient tended to misinterpret random events as meaningful, experienced heightened stimulus generalization, and responded best to in vivo exposure, making their treatment journey both challenging and distinct.

ABSTRACTDifferential reinforcement (DR) procedures involve systematically arranging the environment to increase the future frequency of socially important behaviors while minimizing or eliminating problem behaviors. The purpose of the present study was to compare the effects of computerized stimulus equivalence‐based instruction (EBI) to a pre‐recorded voiceover PowerPoint lecture to teach definitions and examples of differential reinforcement procedures to college students. The three classes comprised textual stimuli characterizing differential reinforcement of other (DRO), alternative (DRA), and incompatible (DRI) behavior. Each class contained three members: name, definition, and short vignette examples. To program for generalization, two vignette exemplars were used during training while a third exemplar was used to assess stimulus generalization. We used a between‐subjects group design to compare pretest and posttest performances of EBI and lecture participants across (a) computer match‐to‐sample (MTS), (b) card sorting, and (c) written tests (fill‐in and multiple‐choice), with the latter two used to determine the degree to which class‐consistent responding generalized from selection‐based responding to other response topographies (i.e., sorting and writing). Results demonstrated that EBI produced greater score increases than lecture for MTS and card sorting tests, but increases were comparable for the two groups for both fill‐in and multiple‐choice written tests. Another posttest at 1 week showed maintenance of performance gains. Implications for using EBI to teach behavior analytic content are discussed.

Tracking Eye Fixations during Stimulus Generalization Tests

Emotional intensity can produce both optimal and suboptimal effects on learning and memory. While emotional events tend to be better remembered, memory performance can follow an inverted U-shaped curve with increasing intensity. The strength of Pavlovian conditioning tends to increase linearly with the intensity of the aversive outcome, but leads to greater stimulus generalization. Here, we combined elements of episodic memory and Pavlovian conditioning into a single paradigm to investigate the effects of varying outcome intensities on conditioned fear responses and episodic memory. Participants encoded trial-unique images from two semantic categories as conditioned stimuli (CS+ and CS−) before (preconditioning), during, and after (extinction) acquisition. We systematically varied the intensity of the unconditioned stimulus (US) during acquisition between-groups as a nonaversive tone, a low-intensity electrical shock, or a high-intensity electrical shock paired with a loud static noise. Results showed that conditioned skin conductance responses scaled linearly with US intensity during acquisition, with a high-intensity US leading to greater resistance to extinction and stronger 24 h fear recovery. However, 24 h recognition memory produced an inverted U-shaped relationship, with better recognition memory for CSs encoded before (retroactive), during, and following conditioning using a low-intensity US. These findings suggest a dissociation between optimal levels of emotional intensity on explicit and implicit learning and memory performance.

Assessment of reduction in stimulus generalization of ethanol-seeking during recovery: A rapid procedure

PurposeIntersectionality addresses complex avenues of oppression that emanate at the intersections of one’s identities. However, the intersectional framework assumes static identities, which are increasingly being acknowledged for their fluidity. This research explored the extent of the fluidity of social identities to draw implications for the application of the framework in research.Design/methodology/approach27 participants from a post-graduate elective course on diversity and inclusion identified their significant social identities, and submitted a write-up using hermeneutic phenomenology in which the participants shared their lived experiences of the fluidity of their social identities in different spaces they occupy or find themselves in.FindingsFluidity-triggering stimuli in different environments and their associations with identity-related motives were uncovered using thematic analysis. Stimuli operating at micro-, meso- and macro-levels rationally explained identity fluidity. However, in addition to types, intensity and frequency of stimuli, psychological factors, such as identity status, were decisive in determining the degree of generalization of stimuli across individuals and spaces that significantly influenced identity fluidity.Originality/valueThis research explored the extent of the fluidity of social identities to draw implications for the application of the intersectional framework in research. The findings contribute to future research by identifying limitations of the intersectional framework based on the fluidity of social identities arising from environmental stimuli that operate at micro-, meso- and macro-levels, and the extent of psychological generalization of these stimuli across spaces.

The delicate balance between discrimination and generalization of responses is crucial for survival in our ever-changing environment. In particular, it is important to understand how stimulus discrimination affects the level of stimulus generalization. For example, when we use non-differential training for Pavlovian eyeblink conditioning to investigate generalization of cerebellar-related eyelid motor responses, we find generalization effects on amount, amplitude and timing of the conditioned responses. However, it is unknown what the generalization effects are following differential training. We trained mice to close their eyelids to a 10 kHz tone with an air-puff as the reinforcing stimulus (CS+), while alternatingly exposing them to a tone frequency of either 4 kHz, 9 kHz or 9.5 kHz without the air-puff (CS-) during the training blocks. We tested the generalization effects during the expression of the responses after the training period with tones ranging from 2 kHz to 20 kHz. Our results show that the level of generalization tended to positively correlate with the difference between the CS+ and the CS- training stimuli. These effects of generalization were found for the probability, amplitude but not for the timing of the conditioned eyelid responses. These data indicate the specificity of the generalization effects following differential versus non-differential training, highlighting the relevance of discrimination learning for stimulus generalization.

Generalization, the tendency to respond in the same way to different but similar stimuli, is one of the main cognitive abilities that make category formation possible and thus is a prerequisite for efficiency in learning. Individuals with autism spectrum disorder (ASD) experience pervasive difficulty with producing generalized responses across materials, people, places, and contexts. Increasing evidence suggests that “ASD-like” social impairments appear endogenously and spontaneously in family dogs providing a high-validity model for understanding the phenotypic expression of human ASD. The present study aims to further investigate the dog model of ASD by the approach of searching for analogues in dogs showing “ASD-like” social impairments of cognitive phenomena in humans specific to ASD, specifically impairments of generalization abilities. We have tested 18 family dogs with formerly established “ASD-like” behaviour scores (F1, F2, F3) in a generalization task involving three conditions (size, colour and texture). We found a significant association between F1 scores and test performance as well as improvement during testing sessions. Our study provides further support for the notion that dogs with lower social competence—similarly to humans with ASD—exhibit attentional and perceptual abnormalities, such as being sensitive to minor changes to a non-adaptive extent.

Generalization of a positive-feature interoceptive morphine occasion setter across the rat estrous cycle

Voluntary running in activity wheels by rats leads to a Pavlovian conditioned aversion to the flavour consumed immediately before the running, causing the rats to avoid that flavour. This learning process, known as running-based flavour avoidance learning (FAL), is weakened when the rats have had repeated exposure to the wheels before. According to the associative account, the association between the background context and running established during the preexposure phase blocks the conditioning of the target flavour because the running is highly predictable by the background context from the outset of the FAL phase. Experiments 1 and 2 examined this account by introducing another flavour as a cue signalling wheel access during the preexposure phase. In the framework of the associative account, the introduction of this cue should impede the formation of the context-running association during the preexposure phase, thereby hindering the contextual blocking of aversive conditioning for the target flavour in the FAL phase. This would result in unweakened FAL. Although the results of Experiment 1 align with this prediction, in Experiment 2, when highly distinct flavours were used as the target and second cues, the preexposure effect was not eliminated. This contradicts the predictions of the associative account, indicating that Experiment 1 may have been influenced by stimulus generalisation. In Experiment 3, changing background contexts between the preexposure and FAL phases had no impact on the preexposure effect, contrary to the predictions of the associative account. In general, the associative account was not supported.

How memory representations are shaped during and after their encoding is a central question in the study of human memory. Recognition responses to stimuli that are similar to those observed previously can hint at the fidelity of the memories or point to processes of generalization at the expense of precise memory representations. Experimental studies utilizing this approach showed that emotions and sleep both influence these responses. Sleep, and more specifically rapid eye movement sleep, is assumed to facilitate the generalization of emotional memories. We studied mnemonic discrimination by the emotional variant of the Mnemonic Separation Task in participants (N = 113) who spent a daytime nap between learning and testing compared with another group that spent an equivalent time awake between the two sessions. Our findings indicate that the discrimination of similar but previously not seen items from previously seen ones is enhanced in case of negative compared with neutral and positive stimuli. Moreover, whereas the sleep and the wake groups did not differ in memory performance, participants entering rapid eye movement sleep exhibited increased generalization of emotional memories. Our findings indicate that entering into rapid eye movement sleep during a daytime nap shapes emotional memories in a way that enhances recognition at the expense of detailed memory representations.

Although events are not always known to be important when they occur, people can remember details about such incidentally encoded information using episodic memory. Sheridan et al. (2024) argued that rats replayed episodic memories of incidentally encoded information in an unexpected assessment of memory. In one task, rats reported the third-last item in an explicitly encoded list of trial-unique odors. In a second task, rats foraged in a radial maze in the absence of odors. On a critical test, rats foraged in the maze, but scented lids covered the food. Next, memory of the third-last odor was assessed. The rats correctly answered the unexpected question. Because the odors used in the critical test were the same as those used during training, automatically encoding odors for the purpose of taking an upcoming test of memory (stimulus generalization) may have been encouraged. Here, we provided an opportunity for incidental encoding of novel odors. Previously trained rats foraged in the radial maze with entirely novel odors covering the food. Next, memory of the third-last odor was assessed. The rats correctly answered the unexpected question. High accuracy when confronted with novel odors provides evidence that the rats did not automatically encode odors for the purpose of taking an upcoming test, ruling out stimulus generalization. We conclude that rats encode multiple pieces of putatively unimportant information, and later replayed a stream of novel episodic memories when that information was needed to solve an unexpected problem.

Past studies have shown that pigeons can learn complex categories and can also remember large numbers of individual objects. In recent work, Cook et al. Psychonomic Bulletin & Review, 28, 548-555, (2021) provided evidence that pigeons may use a dynamic combination of both category-based information and item-specific memorization to solve a categorical variation of the mid-session reversal (MSR) task, which is an influential task for exploring the nature of temporally organized behaviors in animals. To provide greater insight into these pigeons' behaviors, in this article we developed and investigated different computational models and their variations to account for these data. Of these, two models emerged as good candidates. One was a multinomial-processing-tree categorization/memory model, formalizing the two-process mechanism initially proposed by Cook et al. Psychonomic Bulletin & Review, 28, 548-555, (2021). The second was a new object/time-coding model, which posits the storage of object-specific memories with an additional within-session time code and assumes that a basic stimulus generalization process underlies the pigeons' choice behavior. Both provided high-quality fits to the published sets of training and transfer data collected in the categorical MSR task. These computational efforts give deeper insights into the theoretical mechanisms underlying the temporal and sequential structure of behavior in animals and stimulate future empirical research further revealing the organization of the pigeons' cognitive processes.

Errorless learning strategies such as stimulus fading and stimulus shaping are commonly used to teach complex skills like categorisation and concept formation. Despite widespread use, very few studies have explored the comparative effectiveness of these procedures in well-controlled analyses. The vast majority of existing studies have been undertaken with clinical populations and have involved small numbers of participants (e.g., Single-case designs). The present study sought to compare stimulus fading, stimulus shaping, and trial-and-error learning in a perceptual categorisation task. In Experiment 1, we found robust benefits of stimulus shaping when compared to stimulus fading or trial-and-error learning on measures of initial acquisition of discrimination and one measure of stimulus generalisation. These findings were replicated in a second experiment in which the dimension of fading/shaping was changed from a modification of the comparison stimuli (S-) to a modification of the target stimulus (S +). We discuss the implications of our findings for the selection of errorless learning strategies in clinical settings.

The long shadow beyond lockdown: Board chairs’ professional pandemic experiences and corporate investments

Peter J. Urcuioli passed away on November 27, 2022, after a decade-long battle with Large Cell Non-Hodgkin's Lymphoma. Peter touched the lives of many people, and we-his mentees-are honored to write about some of his accomplishments. Peter completed his undergraduate training at the University of New Hampshire, where he enjoyed time learning about experimental psychology and behavior analysis by working in Tony Nevin's rat lab. Peter saw his career in large part as a reflection of Tony's mentoring and friendship. Peter had fond memories of student dinners at Tony's house in Durham, and they maintained their personal connection for more than 40 years. Peter completed his graduate training in experimental psychology at Dalhousie University in 1979, under the mentorship of Werner Honig. These years in Canada prompted his interest in stimulus generalization and discrimination (e.g., Honig & Urcuioli, 1981), which eventually led to a fruitful and influential career in the general field of stimulus control. He moved from Nova Scotia to Texas to continue his research in basic stimulus control and vision in pigeons as a postdoctoral fellow with Tony Wright at the University of Texas Health Science Center at Houston. In 1981, Peter joined the Department of Psychological Sciences at Purdue University, where he quickly earned Full Professor. Over the years, he developed and maintained research collaborations with several labs, which often led to lifelong friendships. He retired from Purdue in 2020, earning the status of Emeritus Professor. There are many ways to measure the impact of Peter's career. We would like to highlight some of Peter's many professional accomplishments and his contributions to science across several domains of the experimental analysis of behavior. More than that, we want to highlight the influence that Peter had on those around him. Peter was an excellent teacher; he was awarded