Example methods, apparatus/systems and articles of manufacture for determining intensity of a biological response to a presentation are disclosed. An example method includes accessing galvanic skin response (GSR) data obtained from a subject while exposed to a presentation. The GSR data includes a plurality of trough-to-peak instances. The example method includes generating a GSR intensity profile by assigning trough-to-peak scores to corresponding ones of the trough-to-peak instances, defining a plurality of time windows, and assigning window scores to corresponding ones of the time windows based on the trough-to-peaks scores of the trough-to-peak instances occurring within the corresponding time windows. The example method also includes determining an effectiveness of the presentation based on the window scores of the GSR intensity profile.