According to research studying the processes underlying decisions, a two-channel mechanism connects attention and choices: top-down and bottom-up processes. To identify the magnitude of each channel, we exogenously varied information intake by systematically interrupting participants' decision processes in Study 1 ( N = 116). Results showed that participants were more likely to choose a predetermined target option. Because selection effects limited the interpretation of the results, we used a sequential-presentation paradigm in Study 2 (preregistered, N = 100). To partial out bottom-up effects of attention on choices, in particular, we presented alternatives by mirroring the gaze patterns of autonomous decision makers. Results revealed that final fixations successfully predicted choices when experimentally manipulated (bottom up). Specifically, up to 11.32% of the link between attention and choices is driven by exogenously guided attention (1.19% change in choices overall), while the remaining variance is explained by top-down preference formation.