Provided are a method, a device, a system, and a program for evaluating similarity of brain activity with respect to an object to be evaluated, using data obtained by a simple measurement of brain waves. Brain wave data related to cognitive processing with respect to a plurality of sensory stimuli are dimensionally compressed, and a distribution of the object to be evaluated is displayed on a two-dimensional plane or three-dimensionally. In this way, similarity of brain information with respect to the plurality of sensory stimuli is evaluated, and the similarity is visualized. The brain wave data related to the cognitive processing include brain wave data upon selection of a stimulus as a target, and brain wave data caused by a non-target stimulus event.