There is provided a method for controlling a determining apparatus including: a first pixel for displaying a first image; a second pixel for displaying a second image; a light shielding member that allows the first image to be viewed from a first direction and blocks the first image from a second direction, and allows the second image to be viewed from the second direction and blocks the second image from the first direction; a first sensor provided for the first pixel and detecting the quantity of light coming from the first direction; and a second sensor provided for the second pixel and detecting the quantity of light coming from the second direction. The method includes: storing at least one frame of the results of detection of the first and second sensors; and after obtaining the present results of detection of the first and second sensors, determining whether an object approaches from the first direction or the second direction from the result of comparison between the stored detection results of one frame and the results of detection of present one frame.