Abstract

The work presented here is at the meeting point of two branches of visual search research, one of which focuses on the proposition that visual search is guided by preparatory internal representations of targets (i.e., search templates: e.g., Bravo & Farid, 2009; 2012; Castelhano & Heaven, 2010; Duncan & Humphreys, 1989; Malcolm & Henderson 2009; 2010; Schmidt & Zelinsky, 2009; Vickery, King, & Jiang, 2005; Wolfe, 2007; Wolfe, Cave, & Franzel, 1989; Yang & Zelinsky, 2009), and the other of which focuses on investigating target detection in naturalistic search environments (e.g., Delorme, Richard, & Fabre-Thorpe, 2010; Delorme, Rousselet, Macé, & Fabre-Thorpe, 2004; Li, VanRullen, Koch, & Perona, 2002; Peelen, Fei-Fei, & Kastner, 2009; Peelen & Kastner, 2011; Thorpe, Fize, & Marlot, 1996; VanRullen & Thorpe, 2001). The search template for objects presented in naturalistic scenes is relatively unknown in terms of its content and characteristics, neural underpinnings, and individual differences in its representation. This thesis explores these topics in depth using behavioral and neurostimulation methods in four experimental chapters.