In the course of a typical day, humans encounter numerous stimuli that are detected, identified, and put into context within a few hundred of milliseconds. Remarkably, several recent studies demonstrated that many of these high-level processes can take place even when the stimuli are invisible: observers were found to read and process the meaning of words (Abrams, Klinger, & Greenwald,
2002; Armstrong & Dienes,
2013; Costello, Jiang, Baartman, McGlennen, & He,
2009; Dehaene, Kerszberg, & Changeux,
1998; Lamy, Mudrik, & Deouell,
2008; Reber & Henke,
2012); process semantic incongruencies in written sentences (Sklar et al.,
2012) and visual scenes (Mudrik, Breska, Lamy, & Deouell,
2011); perform arithmetic operations (Bahrami et al.,
2010; Garcia-Orza, Damas-Lopez, Matas, & Rodriguez,
2009; Ric & Muller,
2012); categorize faces (Barbot & Kouider,
2012; Stein, Senju, Peelen, & Sterzer,
2011b) and other objects (Almeida, Mahon, Nakayama, & Caramazza,
2008; Poscoliero, Marzi, & Girelli,
2013); process emotions (Adams, Gray, Garner, & Graf,
2010; Faivre, Berthet, & Kouider,
2012; Yang, Zald, & Blake,
2007); and exercise executive functions (Capa, Bustin, Cleeremans, & Hansenne,
2011; Lau & Passingham,
2007; van Gaal, Ridderinkhof, Fahrenfort, Scholte, & Lamme,
2008) in the absence of perceptual awareness (for reviews, see Kouider & Dehaene,
2007; Lin & He,
2009; Mudrik, Faivre, & Koch,
2014; van Gaal & Lamme,
2012).