Figure 2. Fate of unattended stimuli. A, Responses evoked by task-irrelevant, unattended peripheral motion (adapted from Rees et al.,1997). During a low-load linguistic task (determining whether words were lowercase or uppercase), strong responses were observed in area MT (red line). During a high-load condition (determining whether words contained two syllables), such responses were eliminated. B, C, Responses evoked by fearful, happy, or neutral faces. Estimated responses for the right amygdala (B) and right fusiform gyrus (C) regions of interest as a function of attention and valence. The expression of a valence effect (e.g., responses to fearful faces greater than responses to neutralfaces) was observed only when the faces were attended. For unattended faces, no difference in the responses to different expressions was observed; in fact, responses were not significantly greater than zero. The results suggest that attention is required for the processing of stimulus valence. FA, Fearful attended; FU, fearful unattended; HA, happy attended; HU, happy unattended; NA, neutral attended; NU, neutral unattended. Adapted from Pessoa et al. (2002).