The Pupillary Light Response Reveals the Focus of Covert Visual Attention Mathôt, Sebastiaan ; van der Linden, Lotje ; Grainger, Jonathan ; Vitu, Françoise Abstract Publication: PLoS ONE Pub Date: October 2013 DOI: 10.1371/journal.pone.0078168 Bibcode: 2013PLoSO...878168M