Mandatory Processing of Irrelevant Fearful Face Features in Visual Search Daniela B. Fenker 1 , Dorothee Heipertz 1 , Carsten N. Boehler 2 , Mircea A. Schoenfeld 1,2 , Tömme Noesselt 1 , Hans-Jochen Heinze 1,2 , Emrah Duezel 1,3 , and Jens-Max Hopf 1,2 Abstract ■ Faces expressing fear may attract attention in an automatic bottom–up fashion. Here we address this issue with magneto- encephalographic (MEG) recordings in subjects performing a demanding visual search combined with the presentation of irrelevant neutral or fearful faces. The impact of the facesʼ emo- tional expression on attentional selection was assessed by ana- lyzing the N2pc component—a modulation of the event-related magnetic field response known to reflect attentional focusing in visual search. We observed that lateralized fearful faces elicited an N2pc approximately between 240 and 400 msec in ventral extrastriate cortex that was independent of the N2pc reflecting target selection in visual search. Despite their clear influence on neural processing, fearful faces did not significantly influence behavioral performance. To clarify this discrepancy, we further performed an MEG experiment in which the demands of the search task were reduced. Under those conditions, lateralized fearful faces elicited an N2pc response that was again indepen- dent of the N2pc response to the search target. Behavioral per- formance was, however, influenced in a significant manner, suggesting that for behavioral effects to appear, sufficient atten- tional resources need to be left unoccupied by the search task—a notion put forward by the perceptual load theory. Our observa- tions are taken to indicate that irrelevant fearful faces influence attentional processing in extrastriate visual cortex in an automatic fashion and independent of other task-relevant attentional opera- tions. However, this may not necessarily be echoed at the be- havioral level as long as task-relevant selection operations exhaust attentional resources. ■ INTRODUCTION Given the general ecological importance of facial gestures for human social interactions, it is not surprising that faces expressing emotional states are suspected to cap- ture attention in an automatic way (Dolan & Vuilleumier, 2003; Ohman, Lundqvist, & Esteves, 2001; Vuilleumier & Schwartz, 2001; White, 1995). Although face features per se may not necessarily give rise to attentional capture (Nothdurft, 1993), the emotional valence of faces is sug- gested to be mandatorily registered outside the focus of attention (Lavie, Ro, & Russell, 2003; Vuilleumier, 2002; Morris, Ohman, & Dolan, 1999). In particular, negative emotional valence was observed to speed face identifica- tion in visual search significantly (Eastwood, Smilek, & Merikle, 2001, 2003; Fox et al., 2000; Hansen & Hansen, 1988), which was taken to indicate that negative valence may act like a pop-out feature in guiding attentional focus- ing automatically (e.g., anger superiority effect). However, the results of Hansen and Hansen (1988) obtained with natural face images (Ekman & Friesen, 1978) were chal- lenged by attesting low-level stimulus confounds (Purcell, Stewart, & Skov, 1996) or configurational shortcomings (Cave & Batty, 2006; Horstmann & Bauland, 2006). Purcell et al. (1996), for example, demonstrated that conspicuous black spots were more frequent in threatening than in happy faces, which presumably gave rise to the capture effect. Horstmann and Bauland (2006) suggested that the “anger superiority effect” demonstrated with angry faces embedded in friendly face distractors may rather reflect the fact that observers were more efficient in rejecting happy distractors than in detecting angry target faces. To avoid low-level stimulus confounds, a number of stud- ies used schematic face drawings (Eastwood et al., 2001; Ohman et al., 2001; Fox et al., 2000; White, 1995) to show that negative emotional valence undergoes automatic pri- ority decoding in visual search. These studies, however, provided rather heterogeneous and partially conflicting results and were overall not entirely conclusive. Many of the observations may simply be attributable to lower level configurational confounds and not to the emotional valence of the face drawings (Cave & Batty, 2006; Horstmann & Bauland, 2006). Regarding the automatic capture hypothesis, there are further issues to be considered. In simple search tasks, attentional capture by salient singletons has been shown 1 Otto-von-Guericke University, Magdeburg, Germany, 2 Leibniz Institute for Neurobiology, Magdeburg, Germany, 3 University College London, London, UK © 2010 Massachusetts Institute of Technology Journal of Cognitive Neuroscience 22:12, pp. 2926–2938