A method includes (a) obtaining a search word, (b) obtaining first to third concept maps including words and semantic distances between the words, (c) obtaining a first association map including degrees of association indicating how close the semantic distances included in the first and second concept maps are to each other; (d) obtaining a second association map including degrees of association indicating how close the semantic distances included in the first to third concept maps are to one another, (e) extracting, from the words as an associated word, at least one word whose difference between the degree of association with the search word included in the first association map and the degree of association with the search word included in the second association map is equal to or larger than a first threshold, and (f) outputting a result of a search based on the search word and the associated word.