title: An almost general theory of mean size perception.
abstract: A general explanation for the observer's ability to judge the mean size of simple geometrical figures, such as circles, was advanced. Results indicated that, contrary to what would be predicted by statistical averaging, the precision of mean size perception decreases with the number of judged elements. Since mean size discrimination was insensitive to how total size differences were distributed among individual elements, this suggests that the observer has a limited cognitive access to the size of individual elements pooled together in a compulsory manner before size information reaches awareness. Confirming the associative law of addition means, observers are indeed sensitive to the mean, not the sizes of individual elements. All existing data can be explained by an almost general theory, namely, the Noise and Selection (N&S) Theory, formulated in exact quantitative terms, implementing two familiar psychophysical principles: the size of an element cannot be measured with absolute accuracy and only a limited number of elements can be taken into account in the computation of the average size. It was concluded that the computation of ensemble characteristics is not necessarily a tool for surpassing the capacity limitations of perceptual processing.
authors.affiliation: Department of Psychology, University of Tartu, Estonia. juri.allik@ut.ee
authors.forename: Jüri
authors.initials: J
authors.lastname: Allik
authors.forename: Mai
authors.initials: M
authors.lastname: Toom
authors.forename: Aire
authors.initials: A
authors.lastname: Raidvee
authors.forename: Kristiina
authors.initials: K
authors.lastname: Averin
authors.forename: Kairi
authors.initials: K
authors.lastname: Kreegipuu
mesh_terms: D004192:Discrimination, Psychological / Q000502:physiology; D006801:Humans; D007600:Judgment / Q000502:physiology; D008962:Models, Theoretical; D010775:Photic Stimulation / Q000379:methods; D011594:Psychometrics; D012684:Sensory Thresholds / Q000502:physiology; D012858:Size Perception / Q000502:physiology*