“…One influential idea is the observation that the first principal component of (unnormalized) faces is informative about gender (Abdi et al, 1995;O'Toole, Abdi, Deffenbacher, & Valentin, 1993;O'Toole et al, 1998;Sirovich & Kirby, 1987;Turk & Pentland, 1991;Valentin, Abdi, Edelman, & O'Toole, 1997). To evaluate the algorithms described above and their plausibility as models of human face processing, their overall performance (in percentage correct) is compared against the performance of human observers (Blackwell et al, 1997;Hancock, Bruce, & Burton, 1998). We extend these studies by trying to build algorithms which not only predict the over-all percentage correct of human observers, but also their responses on a stimulus by stimulus level (Graf, Wichmann, Bulthoff, & Scholkopf, 2006).…”