[jangxx]

Back in high school a teacher told us this "fact" as well and I remember being very surprised because it did not match my experience at all. Many times have I tested this theory since, e.g. when waiting at a pedestrian traffic light, looking off to the side so that the light is on the very edge of my peripheral vision, seeing if I can perceive it turn green and always being able to. Of course this is not proof that there are no people who can't do this, but I definitely know that I can see color at the edge of my peripheral vision and I've come to assume that this just varies from person to person.