1. A computer-implemented method of digital image analysis, the method comprising: obtaining first digital video of a human subject that indicates facial expressions of the human subject; performing micro-expression analysis on the human subject using the first digital video; comparing results of the performed micro-expression analysis with content of a presentation determined to have been provided to the human subject at the same time that particular portions of the digital video were initially captured; and modifying a manner of performing interaction with the human subject or other human subjects based on the comparing of results.