WEBVTT 00:00:00.302 --> 00:00:02.627 So, we've been going through all of the others things NOTE Paragraph 00:00:02.627 --> 00:00:04.953 that we were assuming are held constant 00:00:04.953 --> 00:00:08.370 in order to be moving along one demand curve. 00:00:08.370 --> 00:00:10.033 And now let's list a few other[s]. 00:00:10.033 --> 00:00:11.511 And before I do any more of them, 00:00:11.511 --> 00:00:12.996 let's talk about the ones we already talked about. 00:00:12.996 --> 00:00:16.322 So – one– we said that one of the things we held constant – 00:00:16.322 --> 00:00:17.452 (Let me write this down.) 00:00:17.452 --> 00:00:22.258 So – (WRITING: held constant.) 00:00:22.258 --> 00:00:25.712 One of the things that we held constant to move along 00:00:25.712 --> 00:00:28.503 one demand curve, for the demand itself not to shift – 00:00:28.503 --> 00:00:30.067 for the curve not to shift – 00:00:30.067 --> 00:00:37.756 is price of related goods. [WRITING] 00:00:37.756 --> 00:00:40.898 The other thing we assumed that's being held constant 00:00:40.898 --> 00:00:45.764 is price expectations for our good. [WRITING] 00:00:45.764 --> 00:00:48.176 And now we'll list a couple of them that are fairly intuitive. 00:00:48.176 --> 00:00:49.762 But you'll see that in the next few videos, 00:00:49.762 --> 00:00:52.717 that there are often special cases even to this. 00:00:52.717 --> 00:00:55.344 So, the other thing that we've been holding constant 00:00:55.344 --> 00:00:59.464 to stay on one demand curve is income. 00:00:59.464 --> 00:01:01.192 And this one is fairly intuitive. 00:01:01.192 --> 00:01:05.122 What happens if everyone's income were to increase? 00:01:05.122 --> 00:01:07.712 And, in real terms, it were to actually increase? 00:01:07.712 --> 00:01:08.682 Well, then, all of a sudden, 00:01:08.682 --> 00:01:10.328 they have more disposable income – 00:01:10.328 --> 00:01:12.636 naybe to spend on something like e-books. 00:01:12.636 --> 00:01:14.670 And so, for any given price point, 00:01:14.670 --> 00:01:15.940 the demand would increase. 00:01:15.940 --> 00:01:18.380 And so, it would increase the demand. 00:01:18.380 --> 00:01:20.109 And once again, when we talk about increasing demand, 00:01:20.109 --> 00:01:22.931 we're talking about shifting the entire curve. 00:01:22.931 --> 00:01:25.814 We're not talking about a particular quantity of demand. 00:01:25.814 --> 00:01:30.014 So, income goes up, then [that] increases demand. 00:01:30.014 --> 00:01:32.610 [WRITING] Demand goes up. 00:01:32.610 --> 00:01:36.024 And remember ... when demand goes up, 00:01:36.024 --> 00:01:37.084 we're talking about the whole curve shifting to the right. 00:01:37.100 --> 00:01:38.901 At any given price point, 00:01:38.901 --> 00:01:42.366 we are going to have a larger quantity demanded. 00:01:42.366 --> 00:01:43.987 So the whole curve, 00:01:43.987 --> 00:01:45.268 this whole demand schedule would change. 00:01:45.268 --> 00:01:48.826 And likewise, if income went down, demand would go down. 00:01:48.826 --> 00:01:49.872 And [as] we're going to see in a future video, 00:01:49.872 --> 00:01:51.561 it's actually quite interesting, 00:01:51.561 --> 00:01:53.428 that's not, always ... the case. 00:01:53.428 --> 00:01:58.380 This is only true for normal goods. 00:01:58.380 --> 00:02:00.533 [WRITING] "normal goods." 00:02:00.533 --> 00:02:03.226 And in a future video we'll see goods called "inferior goods," 00:02:03.226 --> 00:02:05.426 where this is NOT necessarily the case. 00:02:05.426 --> 00:02:07.456 Or, by definition, for an inferior good, 00:02:07.456 --> 00:02:09.820 it would not be the case. 00:02:09.820 --> 00:02:12.138 Now the other ones that are somewhat intuitive 00:02:12.138 --> 00:02:15.628 are population. [WRITING] 00:02:15.628 --> 00:02:18.135 Once again, if population goes up -- 00:02:18.135 --> 00:02:20.143 obviously -- at any given price point, 00:02:20.143 --> 00:02:21.798 more people will want it. 00:02:21.798 --> 00:02:23.397 So, it would shift the demand curve to the right -- 00:02:23.397 --> 00:02:25.212 or it would increase demand. 00:02:25.212 --> 00:02:28.888 If population were to go down, it would decrease demand, 00:02:28.888 --> 00:02:32.201 which means shifting the whole curve to the left. 00:02:32.201 --> 00:02:33.679 And then the last one we'll talk about -- 00:02:33.679 --> 00:02:35.647 And remember, we're holding all these things constant 00:02:35.647 --> 00:02:37.487 in order for demand not to change. 00:02:37.487 --> 00:02:40.572 The last thing is just preferences. 00:02:40.572 --> 00:02:42.078 We're assuming that people's tastes 00:02:42.079 --> 00:02:43.752 and preferences don't change 00:02:43.752 --> 00:02:46.903 while we move along a specific demand curve. 00:02:46.903 --> 00:02:50.574 If preferences actually change, then it will change the curve. 00:02:50.574 --> 00:02:56.484 So, for example, if, all of a sudden ... the author of [a] book 00:02:56.484 --> 00:02:58.575 is on some very popular show -- 00:02:58.575 --> 00:03:01.082 talk show -- that tells everyone 00:03:01.082 --> 00:03:03.346 that this is the best book that was ever written, 00:03:03.346 --> 00:03:05.302 then preferences would go up, 00:03:05.302 --> 00:03:07.902 and that would increase the total demand. 00:03:07.902 --> 00:03:09.516 At any given price point, 00:03:09.516 --> 00:03:11.322 more people would be willing to buy the book. 00:03:11.322 --> 00:03:13.665 If, on the other hand, on that same talk show, 00:03:13.665 --> 00:03:16.160 it turns out that they do an exposé 00:03:16.160 --> 00:03:18.617 on the author having this sordid past 00:03:18.617 --> 00:03:20.486 and [they state that] the author plagiarized the whole book, 00:03:20.486 --> 00:03:22.800 then the demand will go down. 00:03:22.800 --> 00:03:25.050 The entire curve, regardless of the price point -- 00:03:25.050 --> 00:03:26.429 at any given price point -- 00:03:26.429 --> 00:03:32.380 the quantity demanded will actually go down.