1. A system configured to use semantic analysis to measure affective response at varying measuring rates, comprising: a semantic analyzer configured to: receive a first segment of content, analyze the first segment utilizing semantic analysis, and output a first indication that a first value related to a predicted emotional response to the first segment does not reach a first predetermined threshold; wherein the first segment comprises data representing text; and a controller configured to select, based on the first indication, a first measuring rate for a device for measuring affective response of a user to the first segment; the semantic analyzer is further configured to: receive a second segment of content, analyze the second segment utilizing semantic analysis, and output a second indication that a second value related to a predicted emotional response to the second segment does reach a second predetermined threshold; wherein the second segment comprises data representing text; the controller is further configured to select, based on the second indication, a second measuring rate for the device for measuring affective response of the user to the second segment; wherein the device takes significantly fewer measurements of affective response, per unit of measurement time, while operating at the first measuring rate, compared to number of measurements of affective response the device takes while operating at the second measuring rate.