Interaction server

An interaction server that holds an interaction by responding to an input made by a user such that the user is urged to make an additional input and by providing response content according to the input of the user, the interaction server comprising:

• processing circuitry;
• and
• a memory configured to store
• a truth table that associates response content including a sentence to be provided to the user with a plurality of searching keywords, and
• a relational table that includes a plurality of related keywords associated with each other;
• wherein the processing circuitry
• receives an input of an input keyword from the user,
• automatically refers to the relational table and acquires a related keyword of a word that matches the input keyword, from the relational table,
• performs searching in the truth table, and acquires response content corresponding to the related keyword, and
• transmits the response content to the user,
• wherein the processing circuitry acquires the input keyword on the basis of an input sentence received from the user,
• wherein the processing circuitry is configured to make a determination to perform searching based on determining whether searching including any of the plurality of related keywords or searching including none of the plurality of related keywords by performing natural language analysis on the input sentence, the natural language analysis being trained via machine learning based on sentence examples of affirmative sentences and negative sentences.