WEBVTT 00:00:08.560 --> 00:00:12.892 Hi. My name is Arielle Eckstut, and I am  the author of 00:00:12.892 --> 00:00:18.254 What Is Color? 50 Questions and Answers on the Science of Color. 00:00:18.254 --> 00:00:22.771 Color is an incredibly difficult subject, 00:00:22.771 --> 00:00:28.182 one that encompasses all kinds of categories of 00:00:28.182 --> 00:00:33.133 science and history and culture – you name it. 00:00:33.280 --> 00:00:39.503 But today in about five minutes I'm going to try to answer this question: 00:00:39.503 --> 00:00:44.746 What is color? And I'm going to do that by starting with yet another question. 00:00:44.746 --> 00:00:48.775 In the fall, do the leaves change color 00:00:48.775 --> 00:00:51.996 if no one is there to see them? 00:00:51.996 --> 00:00:58.758 Take a moment to think about that: Do the leaves change color if no one is there to see them? 00:00:59.076 --> 00:01:04.720 Now, the *obvious answer* to this question is "Of course they change color 00:01:04.720 --> 00:01:09.875 because the color of the leaves are  inherent to the leaves themselves." 00:01:10.000 --> 00:01:13.809 But in fact, that is not true at all, 00:01:13.809 --> 00:01:17.482 and the answer is a resounding *no*. 00:01:17.680 --> 00:01:25.873 If there is not a living being with a brain  observing those leaves, 00:01:25.873 --> 00:01:29.363 the leaves do not change color. 00:01:29.363 --> 00:01:37.326 And the reason for this is that there's no such thing as color without the *eyes* and the *brain*. 00:01:37.600 --> 00:01:44.097 So, different brains process visual information differently. 00:01:44.097 --> 00:01:50.295 And I realized that this idea that color does not exist outside of our perception 00:01:50.295 --> 00:01:54.033 can be very difficult to swallow. 00:01:54.033 --> 00:02:02.257 And in fact, our brains go to great lengths to give us all of the colors that we see. 00:02:02.257 --> 00:02:11.650 The source of our color vision is in our *retina*, a credit-card-thin sheet of neurons in the back of our eyeballs. 00:02:11.760 --> 00:02:15.581 And it's actually a part of our brain, our retina. 00:02:15.581 --> 00:02:20.092 It's the only part of our brain that exists outside of our skulls. 00:02:20.092 --> 00:02:25.908 And our retina is what we typically associate with sight in general. 00:02:29.040 --> 00:02:36.077 If I were to ask you, "Why do we have eyes?" most people would say, "So we can see." 00:02:36.077 --> 00:02:41.430 But that was actually not the original purpose of  our eyes and our retina. 00:02:41.430 --> 00:02:47.781 The original purpose was to tell us when to be awake and when to be asleep. 00:02:47.781 --> 00:02:53.748 So, our eyes sensed when it was light out and when it was dark out, 00:02:53.748 --> 00:02:57.664 and "when" is the most important word here 00:02:57.664 --> 00:03:03.239 because our eyes, our retinas have three different systems: 00:03:03.239 --> 00:03:10.954 the *when system* being the most primitive and the first use of our eyes. 00:03:11.280 --> 00:03:18.800 The next system is the *where system*, and that  tells us where we are situated in the world. 00:03:18.800 --> 00:03:25.984 Are we right at the edge of a cliff? Are we too close to a potential predator? 00:03:26.080 --> 00:03:32.800 Or are we too far to reach a berry that is  ripe that we would like to eat? 00:03:32.800 --> 00:03:36.692 Lastly, we get to our *what system* 00:03:36.692 --> 00:03:40.897 – the system that designers deal with on a daily basis 00:03:40.897 --> 00:03:45.746 but the one that is actually *least important* to our visual system. 00:03:45.746 --> 00:03:50.872 The what system is the system that we use when we are *focusing on something*, 00:03:50.872 --> 00:03:56.370 whether that be a computer screen or a phone or a face or a road sign. 00:03:56.370 --> 00:04:00.120 It's also the system that we use to see color. 00:04:00.120 --> 00:04:04.343 Color scientist Mark Rea has a great quote that I adore: 00:04:04.642 --> 00:04:09.074 "Color is a pigment of our imagination." 00:04:09.074 --> 00:04:16.625 And that really is true. Our imagination plays such a big role when it comes to color. 00:04:16.625 --> 00:04:25.217 And our brains are constantly taking in information from the outside world to help inform us about 00:04:25.217 --> 00:04:30.224 what time of day it is, where we are in the world, what we're looking at, 00:04:30.224 --> 00:04:36.234 which really gets us to the next question,  which is: Why do we see color to begin with?