Title Effects of attentional shifts along the vertical axis on number processing: an eye-tracking study with optokinetic stimulation Authors Arianna Felisatti1*, Mariagrazia Ranzini2*, Elvio Blini3, Matteo Lisi4, & Marco Zorzi3,5 *These authors contributed equally to this work and are listed in alphabetical order Affiliation 1. Department of Psychology, University of Potsdam, Germany 2. Department of Neuroscience, University of Padua, Italy 3. Department of General Psychology, University of Padua, Italy 4. Department of Psychology, University of Essex, UK 5. IRCCS San Camillo Hospital, Venice-Lido, Italy Corresponding Author Prof. Marco Zorzi Department of General Psychology – University of Padua Via Venezia 8 35131 Padova (Italy) Email:
[email protected] Word Count: 6415 (excluding Title, Tables titles, Abstract, Figures legends and References) Tables: 3 Figures: 4 Abstract (Word count = 252) Previous studies suggest that associations between numbers and space are mediated by shifts of visuospatial attention along the horizontal axis. In this study, we investigated the effect of vertical shifts of overt attention, induced by optokinetic stimulation (OKS) and monitored through eye-tracking, in two tasks requiring explicit (number comparison) or implicit (parity judgment) processing of number magnitude. Participants were exposed to black-and-white stripes (OKS) that moved vertically (upward or downward) or remained static (control condition). During the OKS, participants were asked to verbally classify auditory one-digit numbers as larger/smaller than 5 (comparison task; Exp. 1) or as odd/even (parity task; Exp. 2). OKS modulated response times in both experiments. In Exp.1, downward attentional displacement increased the Magnitude effect (slower responses for large numbers) and reduced the Distance effect (slower responses for numbers close to the reference).