INFORMATION PROCESSING DEVICE, INFORMATION PROCESSING SYSTEM, AND COMPUTER PROGRAM PRODUCT FOR CONVERTING A CAUSAL RELATIONSHIP INTO A GENERALIZED EXPRESSION

An information processing device includes one or more hardware processors. The hardware processors acquire a causal relationship included in a target document that is a specific document from causal relationship management information in which one or a plurality of causal relationships are registered, which are extracted from one or a plurality of documents and each which includes a set of a first element and a second element having a relationship; acquire a similar expression of the causal relationship included in the target document based on feature management information in which features of a plurality of words included in one or a plurality of documents are registered; and acquire a generalized expression of the causal relationship included in the target document based on the causal relationship included in the target document and the similar expression.