Multiple object individuation during numerical Stroop


  • This research has been supported by a grant from the Fondazione Cassa di Risparmio di Trento e Rovereto (Italy). We would like to thank Alfonso Caramazza, Roberto Dell'Acqua, and Edward Ester for their comments on an earlier version of the manuscript.

Address correspondence to: Veronica Mazza or Silvia Pagano, Center for Mind/Brain Sciences, University of Trento, Corso Bettini 31, 38068 Rovereto (TN), Italy. E-mail: or


To investigate whether semantic information relative to numbers is retained during multiple object individuation, we recorded N2pc—a neural measure of selection/individuation—during a numerical version of the Stroop task. Participants enumerated a varying number of target digits (1 to 4) whose identity was either congruent or incongruent with their numerosity. N2pc amplitudes increased as a function of target numerosity but were little affected by congruency, suggesting that multiple object individuation is a prenumeric stage that does not encode for the number magnitude of the numerosity of the individuated objects.