00:00 Why do humans have different eye colors?
00:05 And does one color have an evolutionary advantage?
00:08 These are questions scientists have been trying to figure out for decades.
00:12 But now, anthropologists say, lighter eyes might actually have an edge under certain
00:16 conditions.
00:17 Researchers conducted 30-second eye tests, all while dimming the lights incrementally,
00:21 for both brown and blue-eyed participants.
00:23 They found that those with blue eyes were able to read under significantly darker conditions,
00:28 at just 0.7 lux.
00:29 Meanwhile, those with brown eyes tapped out once the light levels fell to just 0.82 lux.
00:34 So why might this be of evolutionary benefit?
00:36 Well, that's still unclear.
00:38 But the researchers say their best guess is that it provided some advantage during the
00:41 low-light months of winter, as mankind moved north, out of Africa.
00:45 Perhaps blue-eyed people were able to hunt for longer, or work longer days next to dimly
00:49 lit campfires.
00:50 Experts warn that this not-yet-peer-reviewed study is still incomplete, and that the photo-processing
00:55 parts of everyone's eyes are the same, regardless of iris color.
00:58 Still, if the results are sound, it shines a light on how such a small mutation can affect
01:03 the course of human history.
01:05 [MUSIC PLAYING]
01:08 (gentle music)
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