1. A method of processing information, the method comprising: identifying a time span in a period of viewing a content based on detection results of the behavioral viewing states of the user viewing the content, the time span being a period, during which a behavioral viewing state of the user is not determined to be a positive state or a negative state; extracting a time period during which an index indicating one of the positive state and the negative state of the user has an unordinary value with respect to values of the other time periods in the time span; and estimating a time period, during which the user has quite possible been in at least one of the positive state and the negative state, based on the time period extracted by the extracting.