RT Journal Article T1 Characterizing visual asymmetries in contrast perception using shaded stimuli. A1 Chacón Gómez, José Carlos A1 Castellanos López, Miguel Ángel A1 Serrano Pedraza, Ignacio AB Previous research has shown a visual asymmetry in shaded stimuli where the perceived contrast depended on the polarity of their dark and light areas (Chacón, 2004). In particular, circles filled out with a top-dark luminance ramp were perceived with higher contrast than top-light ones although both types of stimuli had the same physical contrast. Here, using shaded stimuli, we conducted four experiments in order to find out if the perceived contrast depends on: (a) the contrast level, (b) the type of shading (continuous vs. discrete) and its degree of perceived three-dimensionality, (c) the orientation of the shading, and (d) the sign of the perceived contrast alterations. In all experiments the observers' tasks were to equate the perceived contrast of two sets of elements (usually shaded with opposite luminance polarity), in order to determine the subjective equality point. Results showed that (a) there is a strong difference in perceived contrast between circles filled out with luminance ramp top-dark and top-light that is similar for different contrast levels; (b) we also found asymmetries in contrast perception with different shaded stimuli, and this asymmetry was not related with the perceived three-dimensionality but with the type of shading, being greater for continuous-shading stimuli; PB Scholar One SN 1534-7362 YR 2015 FD 2015-12-01 LK https://hdl.handle.net/20.500.14352/24385 UL https://hdl.handle.net/20.500.14352/24385 LA eng NO Ministerio de Economia y Competitividad (MINECO) DS Docta Complutense RD 4 abr 2025