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Studies of perceptual generalization have recently demonstrated a close relationship between stimulus perception and conditioned responding, suggesting that incorrect stimulus perception might account for certain characteristics of generalization gradients. In this study, we investigated whether common phenomena, such as the area and peak shift in conditioned responding, relate to perceptual errors. After a differential conditioning procedure, in which one circle was paired with the presentation of an aversive picture whereas a different-sized circle was not, we combined a generalization test with a three-alternative forced-choice perceptual categorization task where participants had to indicate on every trial whether the presented circle was one of the two circles from the conditioning phase or a different one, after which US-expectancy ratings were collected. The typical peak and area shift were observed when conditioned responses were plotted on a physical dimension. However, when stimulus perception was incorporated generalization gradients diverged from the typical gradient. Both the area and peak shift largely disappeared when accounting for perceptual errors. These findings demonstrate the need to incorporate perceptual mechanisms in associative models. [ABSTRACT FROM AUTHOR]

Abstract Experimental research has shown that generalization of fear extinction from a generalization stimulus (GS) is minimal compared to generalization of fear extinction from the conditional stimulus itself (CS+). This poses a challenge to extinction-based treatments of anxiety because the exact CS is often not known or unavailable. However, experimental studies failed to disentangle differences in stimulus identity (CS + or GS) from differences in the level of fear (GS typically elicits less fear than CS+). Here, we test the hypothesis that a high level of fear is key to extinction learning and generalization, rather than the identity of the stimulus under extinction (CS + or GS). For that purpose, we took advantage of the peak-shift phenomenon that describes the conditions under which a GS can elicit equal or higher levels of responding, compared to the CS+. Hence, we compared the generalizability of fear extinction following exposure to the CS + itself, to a 'weak' GS that elicits less fear, and to a 'peak' GS that elicits as much fear as the CS+. First, the results replicated, with a new set of stimuli, the observation that extinction of a skin conductance response and US-expectancy generalizes only weakly from a weak GS to CS+. Second, extinction generalized strongly from a peak GS towards CS+, as hypothesized. Third, extinction with the peak GS even outperformed extinction with the CS+, as it generalized more strongly across the generalization gradient. Together, these results support exposure treatment strategies that focus on the fear-eliciting potential of stimuli (often described as a fear hierarchy), rather than their learning history. We propose that stimulus typicality and/or intensity may explain the enhanced effects of a 'peak' GS over the CS+ in enhancing the generalization of fear extinction. Highlights • We invalidated the assumption that fear extinction generalization from a generalization stimulus is limited. • Fear extinction of a generalization stimulus can even be more beneficial than extinguishing fear of the root of anxiety. • Scientific underpinnings to focus on the most fearful generalization stimulus during exposure therapy. [ABSTRACT FROM AUTHOR]

The treatment of anxiety-based psychopathology often hinges upon extinction learning. Research in nutritional neuroscience has observed that the regular consumption of perilla oil (50% alpha-linolenic acid (ALA)) facilitates extinction learning in rats (Yamamoto et al., 1988). However, acute facilitation of extinction learning by oils rich in ALA has not been reported for rats or humans, though the acute consumption of rapeseed oil (10% ALA) has been observed to improve cognitive processing speed in humans (Jones, Sünram-Lea, & Wesnes, 2012). For this reason, the present laboratory work examined the effects of adding walnut oil (12% ALA) to a chocolate milkshake on the acquisition, generalization, and extinction of a fear-based prediction in young adults. It compared performance between subjects. The other participants consumed a similar milkshake with either an equicaloric amount of cream (saturated fat), or with no added fat (control). Acquisition and generalization of the fear-based prediction were similar for all groups. However, those who consumed walnut oil extinguished most rapidly and profoundly. Implications for extinction learning are discussed. [ABSTRACT FROM AUTHOR]

The current experiment investigated whether overgeneralization of fear could be due to an inability to perceptually discriminate the initial fear-evoking stimulus from similar stimuli, as fear learning-induced perceptual impairments have been reported but their influence on generalization gradients remain to be elucidated. Three hundred and sixty-eight healthy volunteers participated in a differential fear conditioning paradigm with circles of different sizes as conditioned stimuli (CS), of which one was paired to an aversive IAPS picture. During generalization, each subject was presented with one of 10 different sized circles including the CSs, and were asked to categorize the stimulus as either a CS or as novel after fear responses were recorded. Linear mixed models were used to investigate differences in fear generalization gradients depending on the participant's perception of the test stimulus. We found that the incorrect perception of a novel stimulus as the initial fear-evoking stimulus strongly boosted fear responses. The current findings demonstrate that a significant number of novel stimuli used to assess generalization are incorrectly identified as the initial fear-evoking stimulus, providing a perceptual account for the observed overgeneralization in panic and anxiety disorders. Accordingly, enhancing perceptual processing may be a promising treatment for targeting excessive fear generalization. [ABSTRACT FROM AUTHOR]

For almost a century, Pavlovian conditioning is the imperative experimental paradigm to investigate the development and generalization of fear. However, despite the rich research tradition, the conceptualization of fear generalization has remained somewhat ambiguous. In this selective review, we focus explicitly on some challenges with the current operationalization of fear generalization and their impact on the ability to make inferences on its clinical potential and underlying processes. The main conclusion is that, despite the strong evidence that learning influences perception, current research has largely neglected the role of perceptual discriminability and its plasticity in fear generalization. We propose an alternative operationalization of generalization, where the essence is that Pavlovian conditioning itself influences the breadth of fear generalization via learning-related changes in perceptual discriminability. Hence a conceptualization of fear generalization is incomplete without an in-depth analysis of processes of perceptual discriminability. Furthermore, this highlights perceptual learning and discriminability as important future targets for pre-clinical and clinical research. [ABSTRACT FROM AUTHOR]

As augmented, virtual and mixed reality have become more user-friendly and affordable, these technologies gained increasing interest from education. Teachers all over the world are triggered by the perceived benefits and start experimenting. However, teachers encounter obstacles to pursue effective implementation. This paper describes how these obstacles are being tackled in Flanders (Belgium) via a large-scale, nation-wide framework for the implementation of augmented, virtual and mixed reality in K-12 technical and vocational education. This framework was designed, adopting an Educational Design Research approach, and consists of five interrelated pillars: hardware, software, professional development of teachers, practice-oriented research, and coordination. The proposed framework provides guidelines, both for researchers and education policy makers. [ABSTRACT FROM AUTHOR]

Eye Movement Desensitization and Reprocessing (EMDR) therapy for posttraumatic stress disorder involves making eye movements (EMs) during recall of a traumatic image. Experimental studies have shown that the dual task decreases self-reported memory vividness and emotionality. However valuable, these data are prone to demand effects and little can be inferred about the mechanism(s) underlying the observed effects. The current research aimed to fill this lacuna by providing two objective tests of memory performance. Experiment I involved a stimulus discrimination task. Findings were that EM during stimulus recall not only reduces self-reported memory vividness, but also slows down reaction time in a task that requires participants to discriminate the stimulus from perceptually similar stimuli. Experiment II involved a fear conditioning paradigm. It was shown that EM during recall of a threatening stimulus intensifies fearful responding to a perceptually similar yet non-threat-related stimulus, as evidenced by increases in danger expectancies and skin conductance responses. The latter result was not corroborated by startle EMG data. Together, the findings suggest that the EM manipulation renders stimulus attributes less accessible for future recall. [ABSTRACT FROM AUTHOR]