A display control method for controlling display of a display panel, the display control method including: obtaining an image by photographing a viewer; determining whether the viewer is sleepy based on the image; controlling a display mode of the display panel based on whether the viewer is sleepy; and generating an output signal for displaying an image on the display panel based on the display mode, wherein the display panel includes a first blue pixel emitting a first blue light and a second blue pixel emitting a second blue light having a different wavelength from the first blue light, and the display mode is classified based on which of the first and second blue pixels are used.