title: Rapid learning of visual ensembles.
abstract: We recently demonstrated that observers are capable of encoding not only summary statistics, such as mean and variance of stimulus ensembles, but also the shape of the ensembles. Here, for the first time, we show the learning dynamics of this process, investigate the possible priors for the distribution shape, and demonstrate that observers are able to learn more complex distributions, such as bimodal ones. We used speeding and slowing of response times between trials (intertrial priming) in visual search for an oddly oriented line to assess internal models of distractor distributions. Experiment 1 demonstrates that two repetitions are sufficient for enabling learning of the shape of uniform distractor distributions. In Experiment 2, we compared Gaussian and uniform distractor distributions, finding that following only two repetitions Gaussian distributions are represented differently than uniform ones. Experiment 3 further showed that when distractor distributions are bimodal (with a 30° distance between two uniform intervals), observers initially treat them as uniform, and only with further repetitions do they begin to treat the distributions as bimodal. In sum, observers do not have strong initial priors for distribution shapes and quickly learn simple ones but have the ability to adjust their representations to more complex feature distributions as information accumulates with further repetitions of the same distractor distribution.
authors.affiliation: Laboratory for Visual Perception and Visuomotor Control, Faculty of Psychology, School of Health Sciences, University of Iceland, Reykjavik, IcelandCognitive Research Lab, Russian Academy of National Economy and Public Administration, Moscow, RussiaDepartment of Psychology, Saint Petersburg State University, Saint Petersburg, Russiaandrey@hi.is.
authors.forename: Andrey
authors.initials: A
authors.lastname: Chetverikov
authors.affiliation: Dipartimento di Psicologia Generale, University of Padova, Padova, ItalyHuman Inspired Technology Research Centre, University of Padova, Padova, Italygianluca.campana@unipd.it.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Campana
authors.affiliation: Laboratory for Visual Perception and Visuomotor Control, Faculty of Psychology, School of Health Sciences, University of Iceland, Reykjavik, Icelandak@hi.is.
authors.forename: Árni
authors.initials: Á
authors.lastname: Kristjánsson
mesh_terms: D001288:Attention / Q000502:physiology; D005260:Female; D006801:Humans; D007858:Learning / Q000502:physiology*; D008297:Male; D016011:Normal Distribution; D011930:Reaction Time / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult