Visual perceptual learning (VPL) is defined as long-term performance enhancement on a visual task as a result of visual experiences, and is regarded as a manifestation of neuroplasticity related to visual processing (Adini, Sagi, & Tsodyks,
2002; Ahissar & Hochstein,
1997; Fahle & Poggio,
2002; Furmanski & Engel,
2000; R. W. Li, Klein, & Levi,
2008a; W. Li, Piëch, & Gilbert,
2004;
2008b; Z. Liu,
1999; Lu & Dosher,
2004; Lu, Chu, Dosher, & Lee,
2005; Mukai et al.,
2007; Sagi,
2010; Sasaki, Nanez, & Watanabe,
2009; Schoups, Vogels, Qian, & Orban,
2001; A. R. Seitz & Dinse,
2007; A. Seitz & Watanabe,
2003; Tsodyks & Gilbert,
2004; Watanabe, Náñez, & Sasaki,
2001; Xu, He, & Ooi,
2010; Yang & Maunsell,
2004; Yotsumoto, Watanabe, & Sasaki,
2008). Research has shown that VPL can be strengthened by two mechanisms: response feedback (M. Herzog & Fahle,
1997,
1999; M. H. Herzog & Fahle,
1998; A. R. Seitz, Nanez, Holloway, Tsushima, & Watanabe,
2006; Shibata, Yamagishi, Ishii, & Kawato,
2009; Weiss, Edelman, & Fahle,
1993) and stabilization/consolidation (Censor, Karni, & Sagi,
2006; Censor & Sagi,
2008; S. C. Mednick et al.,
2002; S. Mednick, Nakayama, & Stickgold,
2003; A. R. Seitz et al.,
2005; Stickgold, James, & Hobson,
2000). It is thought that these two mechanisms operate independently of one another.