Using a Degree-Of-Unexpectedness to Provide Unexpected Recommendations

In the situation where an amount of information on a user action history is small, information which is unexpected and interesting to a user cannot be presented with high accuracy. In order to solve this problem, a general degree of unexpectedness of an item, which does not depend on the user action history, and a degree of preference of the user to the item, which is based on the user action history, are calculated in an integrated manner, whereby the information which is unexpected and interesting to the user is recommended.