1. A device comprising: an image processing module configured to receive a sequence of visual observations of a subject during the execution of an application, wherein the application is a social media application; an emotion determination module configured to: determine an emotional state of the subject based on the sequence of visual observations; and identify a stimulus corresponding to the determined emotional state, wherein the stimulus is an article presented to the subject by the social media application; and a modification module, implemented by a processor, configured to modify the execution of the application from a baseline execution using the emotional state, wherein to modify the execution of the application includes the modification module configured to store a correlation between the emotional state and the stimulus, and wherein the correlation is an indication of at least one of like, dislike, or neutral indication of the article, the indication selected based on the emotional state.