0:00:14.216,0:00:15.704 When we think about learning, 0:00:15.704,0:00:18.365 we often picture students in a classroom or lecture hall, 0:00:18.365,0:00:19.673 books open on their desks, 0:00:19.673,0:00:21.941 listening intently to a teacher or professor 0:00:21.941,0:00:23.599 in the front of the room. 0:00:23.599,0:00:26.511 But in psychology, learning means something else. 0:00:26.511,0:00:30.152 To psychologists, learning is a long-term change in behavior 0:00:30.152,0:00:32.283 that's based on experience. 0:00:32.283,0:00:34.379 Two of the main types of learning are called 0:00:34.379,0:00:36.021 classical conditioning 0:00:36.021,0:00:39.066 and operant, or instrumental, conditioning. 0:00:39.066,0:00:41.969 Let's talk about classical conditioning first. 0:00:41.969,0:00:45.505 In the 1890's, a Russian physiologist named Ivan Pavlov 0:00:45.505,0:00:48.404 did some really famous experiments on dogs. 0:00:48.404,0:00:49.736 He showed dogs some food 0:00:49.736,0:00:51.780 and rang a bell at the same time. 0:00:51.780,0:00:55.290 After a while, the dogs would associate the bell with the food. 0:00:55.290,0:00:56.942 They would learn that when they heard the bell, 0:00:56.942,0:00:58.420 they would get fed. 0:00:58.420,0:01:00.454 Eventually, just ringing the bell 0:01:00.454,0:01:01.915 made the dogs salivate. 0:01:01.915,0:01:05.461 They learned to expect food at the sound of a bell. 0:01:05.461,0:01:07.564 You see, under normal conditions, 0:01:07.564,0:01:11.015 the sight and smell of food causes a dog to salivate. 0:01:11.015,0:01:13.565 We call the food an unconditioned stimulus, 0:01:13.565,0:01:17.564 and we call salivation the unconditioned response. 0:01:17.564,0:01:21.032 Nobody trains a dog to salivate over some steak. 0:01:21.032,0:01:24.313 However, when we pair an unconditioned stimulus like food 0:01:24.313,0:01:26.634 with something that was previously neutral, 0:01:26.634,0:01:28.202 like the sound of a bell, 0:01:28.202,0:01:31.458 that neutral stimulus becomes a conditioned stimulus. 0:01:31.458,0:01:35.086 And so classical conditioning was discovered. 0:01:35.086,0:01:37.463 We see how this works with animals, 0:01:37.463,0:01:39.588 but how does it work with humans? 0:01:39.588,0:01:41.405 In exactly the same way. 0:01:41.405,0:01:44.811 Let's say that one day you go to the doctor to get a shot. 0:01:44.811,0:01:47.766 She says, "Don't worry, this won't hurt a bit," 0:01:47.766,0:01:51.935 and then gives you the most painful shot you've ever had. 0:01:51.935,0:01:54.856 A few weeks later you go to the dentist for a check-up. 0:01:54.856,0:01:56.408 He starts to put a mirror in your mouth 0:01:56.408,0:01:57.859 to examine your teeth, 0:01:57.859,0:02:01.324 and he says, "Don't worry, this won't hurt a bit." 0:02:01.324,0:02:03.747 Even though you know the mirror won't hurt, 0:02:03.747,0:02:05.195 you jump out of the chair and run, 0:02:05.195,0:02:06.924 screaming from the room. 0:02:06.924,0:02:08.604 When you went to get a shot, 0:02:08.604,0:02:10.852 the words, "This won't hurt a bit," 0:02:10.852,0:02:12.467 became a conditioned stimulus 0:02:12.467,0:02:14.628 when they were paired with pain of the shot, 0:02:14.628,0:02:16.637 the unconditioned stimulus, 0:02:16.637,0:02:18.798 which was followed by your conditioned response 0:02:18.798,0:02:21.270 of getting the heck out of there. 0:02:21.270,0:02:24.008 Classical conditioning in action. 0:02:24.008,0:02:26.267 Operant conditioning explains how consequences 0:02:26.267,0:02:29.142 lead to changes in voluntary behavior. 0:02:29.142,0:02:31.478 So how does operant conditioning work? 0:02:31.478,0:02:34.730 There are two main components in operant conditioning: 0:02:34.730,0:02:36.989 reinforcement and punishment. 0:02:36.989,0:02:38.777 Reinforcers make it more likely 0:02:38.777,0:02:40.525 that you'll do something again, 0:02:40.525,0:02:42.708 while punishers make it less likely. 0:02:42.708,0:02:45.869 Reinforcement and punishment can be positive or negative, 0:02:45.869,0:02:48.134 but this doesn't mean good and bad. 0:02:48.134,0:02:50.490 Positive means the addition of a stimulus, 0:02:50.490,0:02:52.951 like getting dessert after you finish your veggies, 0:02:52.951,0:02:55.264 and negative means the removal of a stimulus, 0:02:55.264,0:02:56.965 like getting a night of no homework 0:02:56.965,0:02:59.469 because you did well on an exam. 0:02:59.469,0:03:02.176 Let's look at an example of operant conditioning. 0:03:02.176,0:03:03.995 After eating dinner with your family, 0:03:03.995,0:03:06.522 you clear the table and wash the dishes. 0:03:06.522,0:03:08.724 When you're done, your mom gives you a big hug 0:03:08.724,0:03:11.108 and says, "Thank you for helping me." 0:03:11.108,0:03:13.267 In this situation, your mom's response 0:03:13.267,0:03:15.896 is positive reinforcement if it makes you more likely 0:03:15.896,0:03:17.689 to repeat the operant response, 0:03:17.689,0:03:20.611 which is to clear the table and wash the dishes. 0:03:20.611,0:03:24.038 Operant conditioning is everywhere in our daily lives. 0:03:24.038,0:03:25.533 There aren't many things we do 0:03:25.533,0:03:27.473 that haven't been influenced at some point 0:03:27.473,0:03:29.308 by operant conditioning. 0:03:29.308,0:03:31.080 We even see operant conditioning 0:03:31.080,0:03:34.121 in some extraordinary situations. 0:03:34.121,0:03:36.461 One group of scientists showed the power 0:03:36.461,0:03:37.501 of operant conditioning 0:03:37.501,0:03:40.390 by teaching pigeons to be art connoisseurs. 0:03:40.390,0:03:42.725 Using food as a positive reinforcer, 0:03:42.725,0:03:44.142 scientists have taught pigeons 0:03:44.142,0:03:46.392 to select paintings by Monet 0:03:46.392,0:03:48.388 over those by Picasso. 0:03:48.388,0:03:50.644 When showed works of other artists, 0:03:50.644,0:03:53.436 scientists observed stimulus generalization 0:03:53.436,0:03:55.229 as the pigeons chose the Impressionists 0:03:55.229,0:03:56.754 over the Cubists. 0:03:56.754,0:03:58.609 Maybe next they'll condition the pigeons 0:03:58.609,0:04:00.535 to paint their own masterpieces.