1. A hardware information processing apparatus learning a preference of a user for a content item, the apparatus comprising: acquiring means for acquiring an operation or expression of the user for a certain content item as feedback information; training data generating means for generating training data for the preference learning from the feedback information acquired by the acquiring means; and learning means for learning the preference of the user and how to attach a meaning to the feedback information in association with the training data by using multiple pieces of training data generated by the training data generating means, wherein the training data generating means: calculates an interest level based on the feedback information acquired by the acquiring means; and classifies the feedback information into any of types at least including first feedback information and second feedback information, the first feedback information being determined to have the interest level equal or higher than a first level at which the preference of the user for the certain content item is expressed, the second feedback information being determined to have the interest level lower than the first level.