Learning associations between sensory stimuli and outcomes, and generalizing these associations to novel stimuli, are a fundamental feature of adaptive behavior. Given a noisy olfactory world, stimulus generalization holds unique relevance for the olfactory system. Recent studies suggest that aversive outcomes induce wider generalization curves by modulating discrimination thresholds, but evidence for similar processes in olfaction does not exist. Here, we use a novel olfactory discrimination learning paradigm to address the question of how outcome valence impacts associative learning and generalization in humans. Subjects underwent discrimination learning, where they learned to associate odor mixtures with either aversive (shock) or neutral (air puff) outcomes. We find better olfactory learning for odors associated with aversive compared to neutral outcomes. We further show that generalization gradients are also modulated by outcome valence, with the shock group exhibiting a steeper gradient. Computational modeling revealed that differences in generalization are driven by a narrower excitatory gradient in the shock group, indicating more discriminatory responses. These findings provide novel evidence that olfactory learning and generalization are strongly affected by the valence of outcomes. This adaptive mechanism allows for behavioral flexibility in novel situations with related stimuli and with outcomes of different valences. Because odor stimuli differ considerably from one encounter to the next, adaptive generalization may be especially important in the olfactory system. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

中文翻译：

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厌恶的结果会影响人类嗅觉歧视的学习和泛化。

学习感觉刺激和结果之间的关联，并将这些关联推广到新的刺激，是适应性行为的一个基本特征。给定一个嘈杂的嗅觉世界，刺激泛化与嗅觉系统具有独特的相关性。最近的研究表明，厌恶结果通过调节辨别阈值来诱导更广泛的泛化曲线，但不存在嗅觉中类似过程的证据。在这里，我们使用一种新的嗅觉辨别学习范式来解决结果效价如何影响人类的联想学习和泛化的问题。受试者接受了歧视学习，他们学会了将气味混合物与厌恶（休克）或中性（吹气）结果联系起来。与中性结果相比，我们发现对与厌恶相关的气味有更好的嗅觉学习。我们进一步表明，泛化梯度也受结果效价的调节，冲击组表现出更陡峭的梯度。计算模型显示，泛化的差异是由休克组中较窄的兴奋梯度驱动的，这表明更具歧视性的反应。这些发现提供了新的证据，表明嗅觉学习和泛化受到结果效价的强烈影响。这种适应性机制允许在具有相关刺激和不同效价结果的新情况下行为灵活性。因为气味刺激从一次遭遇到下一次遭遇有很大不同，自适应泛化在嗅觉系统中可能特别重要。