Our eyes are most sensitive to the wavelengths corresponding to the yellow and green colors of the spectrum. Flashy signs and some fire engines are painted in a yellowish-green color to attract our attention. Even simple objects such as highlighters, used to emphasize words or phrases while taking notes, are typically bright yellow and green. When we glance over something or see an object out of the corner of our eyes, we are more likely to notice bright yellowish-green objects than red or blue objects, because the eye is less sensitive to these wavelengths.