Intermixed Rapid Exposure to Similar Stimuli Reduces the Effective Salience of Their Distinctive Features Sánchez, Jesús González Gómez, Ana Brugada Sauras, Isabel de Perceptual learning Comparison Intermixed/blocked effect Effective salience Unitization Intermixed exposure to two similar stimuli, e.g., AX and BX, improves subsequent discrimination between them compared to blocked exposure (the intermixed/blocked effect). Salience modulation models, developed mainly from research with nonhuman animals and exposure to widely spaced similar stimuli, explain this effect in terms of increased salience of the unique elements, A and B. Conversely, results from experiments initially conducted with humans and exposure to close spaced similar stimuli have led to the suggestion that it is the development of well-unitized representations of unique elements that leads to better discrimination, leaving the unique elements with less effective salience. The experiments carried out here aim to replicate the intermixed/blocked effect in rats using an exposure procedure with rapid succession between stimuli and to assess the effective salience of unique elements. In Experiment 1, an aversion to a new flavor, Y, was conditioned and then an external inhibition test with AY was given. In Experiment 2, an aversion to A was conditioned and its extinction was measured on unreinforced trials. In Experiment 3, an aversion to AY was conditioned and the associated aversion to Y was measured. We found after rapid intermixed preexposure a reduction in generalization from the aversive Y element to the compound AY (Experiment 1) as well as a reduction in A’s salience (Experiments 2 and 3) compared to the effects of blocked preexposure. The results are discussed in terms of the various mechanisms underlying perceptual learning, which appear to depend on the details of the task. 2024-04-09T07:21:53Z 2024-04-09T07:21:53Z 2023-05-05 journal article Published version: Sánchez, J., González, A. & de Brugada, I. (2023). Intermixed Rapid Exposure to Similar Stimuli Reduces the Effective Salience of Their Distinctive Features. Journal of Experimental Psychology: Animal Learning and Cognition. DOI:10.1037/xan0000355 https://hdl.handle.net/10481/90515 10.1037/xan0000355 eng http://creativecommons.org/licenses/by-nc-nd/4.0/ open access Attribution-NonCommercial-NoDerivatives 4.0 Internacional American Psychological Association