Research has shown that affective experience is intimately associated with perception in a metaphorically consistent manner (e.g., good = up or light; bad = down or dark). Considering vertical selective attention and affective states, studies have found that people experiencing negative affect or depressive symptoms have a biased inclination to attend to low regions of physical space. This research reveals that affective states may be modified by manipulating vertical selective attention. The purpose of the proposed studies was to determine if a manipulation of vertical selective attention would exert a metaphorically consistent causal influence on affective states (i.e., 'up = happy' and 'down = sad'). In Study 1, vertical selective attention was manipulated by having participants attend to a high, low, or middle area of vertical space on a computer monitor while performing a detection task. In Study 2, vertical selective attention was manipulated by having participants watch an 11-minute informational video that was presented in a high (50 inches from the floor), middle (30 inches from the floor), or low (10 inches from the floor) vertical position. In both studies, the effect of the manipulation was assessed by collecting multiple implicit and explicit measures of mood. Neither of the experimental manipulations affected participants' current mood. The non-significant findings are discussed in terms of null relations, causal direction, psychological realism, and whether vertical selective attention was actually altered. (Dissertation Abstracts)