A novel approach enables an event-based framework for evaluating a media instance based on key events of the media instance. First, physiological responses are derived and aggregated from the physiological data of viewers of the media instance. The key events in the media instance can then be identified, wherein such key events drive and determine the viewers' responses to the media instance. Causal relationship between the viewers' responses to the key events and their surveyed feelings about the media instance can further be established to identify why and what might have caused the viewers to feel the way they do.