The responses of reviewers while reviewing a media composition are captured automatically using imagery and/or audio of the reviewers. The captured information is analyzed to extract response characteristics, such as emotions elicited in reviewers by the media composition. The results of the analysis are synchronized with the composition and fed back to the editor, who may use the emotion response results to influence further editing of the composition. Media composition tools integrate a synchronized representation of reviewers' response characteristics within a timeline display of the composition within the tool's user interface. Emotional responses of individual reviewers or aggregated responses of groups of reviewers may be displayed on reviewer response characteristics tracks within the timeline display.