To provide a display device with high display quality, an eye-friendly display device, a display device with low power consumption, a display device with a reduced change in voltage written to a pixel, or a novel display device. In the display device, a first image signal in which one of grayscale levels of a first pixel and an adjacent second pixel is near white and the other is near black is written. The first image signal is compared with a second image signal. When the grayscale levels of the second image signal written to the first pixel and the second pixel are halftone, the second image signal is written an odd number of times greater than or equal to three times. When the grayscale levels of the second image signal written to the first pixel and the second pixel are near white or near black, the second image signal is written once. The interval between the writing of the first image signal and the writing of the second image signal is longer than or equal to 1 second and shorter than or equal to 10,000 hours.