{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,5]],"date-time":"2026-05-05T03:00:08Z","timestamp":1777950008615,"version":"3.51.4"},"reference-count":36,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,5,4]],"date-time":"2026-05-04T00:00:00Z","timestamp":1777852800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Psychol."],"abstract":"<jats:p>Perceptual learning, which is typically considered an implicit and automatic process, has received little attention in the study of attention deficit hyperactivity disorder (ADHD). In this study, we investigated whether children and adolescents with ADHD show intact perceptual learning using the intermixed-blocks effect, whereby alternating exposure to similar stimuli improves subsequent discrimination compared to block exposure. Eighty-eight participants aged 8 to 16\u202fyears (44 with ADHD and 44 controls) completed a flower counting task while incidentally exposed to two types of visually similar flowers that differed only in the number of petals, without being informed of this distinction. In the interleaved condition, the two types of flowers were alternated within each screen; in the blocked condition, only flowers of one type were presented during the first half of the task and all flowers of the other type during the second half. Discrimination was assessed using a no-prior-warning same-different test. The results showed a robust intermixed-blocked effect in both groups, indicating that implicit learning is preserved in ADHD. However, while control participants in the intermixed group often identified the specific distinguishing feature, participants in the same condition but with ADHD more frequently failed to do so, despite correctly judging the stimuli as different. This dissociation suggests that implicit perceptual learning is preserved in ADHD, but that explicit access to learned information may be impaired. These findings highlight the value of perceptual learning paradigms for unravelling automatic and controlled processes in neurodevelopmental conditions.<\/jats:p>","DOI":"10.3389\/fpsyg.2026.1645399","type":"journal-article","created":{"date-parts":[[2026,5,4]],"date-time":"2026-05-04T05:32:35Z","timestamp":1777872755000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["ADHD and perceptual learning: insights from the intermixed-blocked effect"],"prefix":"10.3389","volume":"17","author":[{"given":"Naiara","family":"Arriola","sequence":"first","affiliation":[{"name":"Facultad de Psicolog\u00eda, University of the Basque Country (EHU)","place":["Donostia\/San Sebasti\u00e1n, Spain"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Eugenia","family":"Marin-Garcia","sequence":"additional","affiliation":[{"name":"Facultad de Psicolog\u00eda, University of the Basque Country (EHU)","place":["Donostia\/San Sebasti\u00e1n, Spain"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yeray","family":"Mera","sequence":"additional","affiliation":[{"name":"Facultad de Psicolog\u00eda, University of the Basque Country (EHU)","place":["Donostia\/San Sebasti\u00e1n, Spain"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Gabriel","family":"Rodr\u00edguez","sequence":"additional","affiliation":[{"name":"Facultad de Psicolog\u00eda, University of the Basque Country (EHU)","place":["Donostia\/San Sebasti\u00e1n, Spain"]}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2026,5,4]]},"reference":[{"key":"ref1","volume-title":"Diagnostic and Statistical Manual of Mental Disorders","year":"2013"},{"key":"ref2","doi-asserted-by":"publisher","first-page":"244","DOI":"10.1016\/j.beproc.2012.09.003","article-title":"Human perceptual learning: the effect of pre-exposure schedule depends on task demands","volume":"91","author":"Angulo","year":"2012","journal-title":"Behav. Process."},{"key":"ref3","doi-asserted-by":"publisher","first-page":"30","DOI":"10.1016\/j.lmot.2014.05.001","article-title":"Is the salience of the distinctive features of similar stimuli affected by stimulus preexposure schedule and length?","volume":"47","author":"Angulo","year":"2014","journal-title":"Learn. Motiv."},{"key":"ref4","doi-asserted-by":"publisher","first-page":"65","DOI":"10.1037\/0033-2909.121.1.65","article-title":"Behavioral inhibition, sustained attention, and executive functions: constructing a unifying theory of ADHD","volume":"121","author":"Barkley","year":"1997","journal-title":"Psychol. Bull."},{"key":"ref5","doi-asserted-by":"publisher","first-page":"489","DOI":"10.1093\/clipsy.8.4.489","article-title":"The inattentive type of ADHD as a distinct disorder: what remains to be done","volume":"8","author":"Barkley","year":"2001","journal-title":"Clin. Psychol. Sci. Pract."},{"key":"ref6","doi-asserted-by":"publisher","first-page":"494","DOI":"10.1080\/87565641.2010.494750","article-title":"Two forms of implicit learning in childhood ADHD","volume":"35","author":"Barnes","year":"2010","journal-title":"Dev. Neuropsychol."},{"key":"ref7","doi-asserted-by":"publisher","first-page":"553","DOI":"10.1037\/0033-2909.130.4.553","article-title":"Individual differences in working memory capacity and dual-process theories of the mind","volume":"130","author":"Barrett","year":"2004","journal-title":"Psychol. Bull."},{"key":"ref8","doi-asserted-by":"publisher","first-page":"757","DOI":"10.1037\/0022-006X.72.5.757","article-title":"Impact of executive function deficits and attention-deficit\/hyperactivity disorder (ADHD) on academic outcomes in children","volume":"72","author":"Biederman","year":"2004","journal-title":"J. Consult. Clin. Psychol."},{"key":"ref9","doi-asserted-by":"publisher","first-page":"117","DOI":"10.1016\/j.tics.2006.01.011","article-title":"Characterizing cognition in ADHD: beyond executive dysfunction","volume":"10","author":"Castellanos","year":"2006","journal-title":"Trends Cogn. Sci."},{"key":"ref10","doi-asserted-by":"publisher","first-page":"e1001293","DOI":"10.1371\/journal.pbio.1001293","article-title":"Reasoning, learning, and creativity: frontal lobe function and human decision-making","volume":"10","author":"Collins","year":"2012","journal-title":"PLoS Biol."},{"key":"ref11","author":"Domuta","year":"2000"},{"key":"ref12","doi-asserted-by":"publisher","first-page":"245","DOI":"10.1080\/02724990344000114","article-title":"Perceptual learning in humans: roles of preexposure schedule, feedback, and discrimination assay","volume":"57","author":"Dwyer","year":"2004","journal-title":"Q. J. Exp. Psychol. B"},{"key":"ref13","doi-asserted-by":"publisher","first-page":"175","DOI":"10.3758\/BF03193146","article-title":"GPower 3: a flexible statistical power analysis program for the social, behavioral, and biomedical sciences","volume":"39","author":"Faul","year":"2007","journal-title":"Behav. Res. Methods"},{"key":"ref14","doi-asserted-by":"publisher","first-page":"967467","DOI":"10.3389\/fpsyg.2022.967467","article-title":"Using position rather than color at the traffic light \u2013 covariation learning-based deviation from instructions in attention deficit\/hyperactivity disorder","volume":"13","author":"Gaschler","year":"2022","journal-title":"Front. Psychol."},{"key":"ref15","volume-title":"Perceptual Learning and Development","author":"Gibson","year":"1969"},{"key":"ref1101","doi-asserted-by":"crossref","DOI":"10.1093\/acprof:oso\/9780198521822.001.0001","volume-title":"Perceptual and associative learning","author":"Hall","year":"1991"},{"key":"ref16","doi-asserted-by":"publisher","first-page":"43","DOI":"10.1080\/02724990244000151","article-title":"Learned changes in the sensitivity of stimulus representations: associative and nonassociative mechanisms","volume":"56","author":"Hall","year":"2003","journal-title":"Q. J. Exp. Psychol."},{"key":"ref17","doi-asserted-by":"publisher","first-page":"335","DOI":"10.1080\/17470218.2017.1339719","article-title":"Attention to perceive, to learn and to respond","volume":"72","author":"Hall","year":"2019","journal-title":"Q. J. Exp. Psychol."},{"key":"ref18","doi-asserted-by":"publisher","first-page":"485","DOI":"10.1037\/0894-4105.18.3.485","article-title":"Neuropsychology of adults with attention-deficit\/hyperactivity disorder: a meta-analytic review","volume":"18","author":"Hervey","year":"2004","journal-title":"Neuropsychology"},{"key":"ref19","doi-asserted-by":"publisher","first-page":"445","DOI":"10.1037\/a0015562","article-title":"Incidental and intentional sequence learning in youth-onset psychosis and attention-deficit\/hyperactivity disorder (ADHD)","volume":"23","author":"Karatekin","year":"2009","journal-title":"Neuropsychology"},{"key":"ref20","doi-asserted-by":"publisher","first-page":"2083","DOI":"10.1080\/17470210600816607","article-title":"Effects of preexposure on stimulus discrimination: an investigation of the mechanisms responsible for human perceptual learning","volume":"59","author":"Lavis","year":"2006","journal-title":"Q. J. Exp. Psychol."},{"key":"ref21","doi-asserted-by":"publisher","first-page":"59","DOI":"10.1348\/026151003321164627","article-title":"Dimensions of executive functioning: evidence from children","volume":"21","author":"Lehto","year":"2003","journal-title":"Br. J. Dev. Psychol."},{"key":"ref22","doi-asserted-by":"publisher","first-page":"119","DOI":"10.3758\/LB.37.2.119","article-title":"Varieties of perceptual learning","volume":"37","author":"Mackintosh","year":"2009","journal-title":"Learn. Behav."},{"key":"ref23","doi-asserted-by":"publisher","first-page":"211","DOI":"10.3758\/bf03200258","article-title":"An elemental model of associative learning: I. Latent inhibition and perceptual learning","volume":"28","author":"McLaren","year":"2000","journal-title":"Anim. Learn. Behav."},{"key":"ref24","doi-asserted-by":"publisher","first-page":"283","DOI":"10.1037\/a0032765","article-title":"Can theories of animal discrimination explain perceptual learning in humans?","volume":"140","author":"Mitchell","year":"2014","journal-title":"Psychol. Bull."},{"key":"ref25","doi-asserted-by":"publisher","first-page":"49","DOI":"10.1006\/cogp.1999.0734","article-title":"The unity and diversity of executive functions and their contributions to complex \"frontal lobe\" tasks: a latent variable analysis","volume":"41","author":"Miyake","year":"2000","journal-title":"Cogn. Psychol."},{"key":"ref26","doi-asserted-by":"publisher","first-page":"124","DOI":"10.1037\/0097-7403.33.2.124","article-title":"Simultaneous presentation of similar stimuli produces perceptual learning in human picture processing","volume":"33","author":"Mundy","year":"2007","journal-title":"J. Exp. Psychol. Anim. Behav. Process."},{"key":"ref27","doi-asserted-by":"publisher","first-page":"250","DOI":"10.1177\/1087054712464392","article-title":"Impaired behavioral inhibition in implicit sequence learning in adult ADHD","volume":"22","author":"Pedersen","year":"2018","journal-title":"J. Atten. Disord."},{"key":"ref28","doi-asserted-by":"publisher","first-page":"942","DOI":"10.1176\/ajp.2007.164.6.942","article-title":"The worldwide prevalence of ADHD: a systematic review and metaregression analysis","volume":"164","author":"Polanczyk","year":"2007","journal-title":"Am. J. Psychiatry"},{"key":"ref29","doi-asserted-by":"publisher","first-page":"855","DOI":"10.1016\/S0022-5371(67)80149-X","article-title":"Implicit learning of artificial grammars","volume":"6","author":"Reber","year":"1967","journal-title":"J. Verbal Learn. Verbal Behav."},{"key":"ref30","doi-asserted-by":"publisher","first-page":"359","DOI":"10.1037\/xan0000113","article-title":"The role of instructions in perceptual learning using complex visual stimuli","volume":"42","author":"Recio","year":"2016","journal-title":"J. Exp. Psychol. Anim. Learn. Cogn."},{"key":"ref31","first-page":"139","article-title":"Simultaneous stimulus preexposure enhances human tactile perceptual learning","volume":"35","author":"Rodr\u00edguez","year":"2014","journal-title":"Psicol\u00f3gica"},{"key":"ref32","doi-asserted-by":"publisher","first-page":"25","DOI":"10.1037\/xan0000278","article-title":"Reconsidering the ability of the stimulus unique features to capture attention: evidence from change blindness and visual search paradigms","volume":"47","author":"Rodr\u00edguez","year":"2021","journal-title":"J. Exp. Psychol. Anim. Learn. Cogn."},{"key":"ref33","doi-asserted-by":"publisher","first-page":"50","DOI":"10.1037\/xan0000389","article-title":"Explicit and implicit intermixed\u2013blocked effects in the absence of instructions requiring the search for differences between visual stimuli","volume":"51","author":"Rodr\u00edguez","year":"2025","journal-title":"J. Exp. Psychol. Anim. Learn. Cogn."},{"key":"ref34","doi-asserted-by":"publisher","first-page":"341","DOI":"10.1016\/j.concog.2009.09.006","article-title":"ADHD children outperform normal children in an artificial grammar implicit learning task: ERP and RT evidence","volume":"19","author":"Rosas","year":"2010","journal-title":"Conscious. Cogn."},{"key":"ref35","doi-asserted-by":"publisher","first-page":"961","DOI":"10.1007\/s10802-010-9422-1","article-title":"Neurocognitive performance in children with ADHD and OCD","volume":"38","author":"Vloet","year":"2010","journal-title":"J. Abnorm. 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