There is provided a system which is able to realize study assistance or a desired appliance operation for a user, even in the absence of an answer input from the user. A service providing system includes an output section for presenting a question to a user, and further presenting sequentially a plurality of options as candidate answers to the question; a signal detection section for measuring an event-related potential of electroencephalograms of the user; and a determination section for determining whether the user has thought each option to be the correct answer or not, based on the event-related potential in a predetermined period after each option is presented, e.g., in a period from about 350 milliseconds to about 450 milliseconds.