WEBVTT 00:00:00.000 --> 00:00:02.680 Greg Gage: Who wouldn't love acing a geography exam, 00:00:02.719 --> 00:00:05.320 remembering all the locations of the countries on a map 00:00:05.360 --> 00:00:08.960 or avoiding embarrassing situations of suddenly forgetting the person's name 00:00:09.000 --> 00:00:10.520 standing right in front of you. 00:00:10.560 --> 00:00:13.240 It turns out that memory, like other muscles in the body, 00:00:13.280 --> 00:00:14.880 can be strengthened and enhanced. 00:00:14.920 --> 00:00:17.000 But instead of practicing with flash cards, 00:00:17.040 --> 00:00:18.560 there may be an interesting way 00:00:18.600 --> 00:00:20.760 that we can hack our memory while we sleep. NOTE Paragraph 00:00:21.000 --> 00:00:23.960 (Music) NOTE Paragraph 00:00:26.200 --> 00:00:27.400 Why do we sleep? 00:00:27.440 --> 00:00:30.640 This has been a question asked since the early days of civilization. 00:00:30.680 --> 00:00:32.920 And while we may not know the exact answer, 00:00:32.960 --> 00:00:36.000 there are a number of really good theories about why we need it. 00:00:36.040 --> 00:00:38.520 Sleep is when the brain transfers short-term memories 00:00:38.560 --> 00:00:40.040 experienced throughout the day 00:00:40.080 --> 00:00:41.320 into long-term memories. 00:00:41.360 --> 00:00:43.540 This process is called memory consolidation, 00:00:43.560 --> 00:00:46.860 and it's the memory consolidation theory that has scientists wondering 00:00:46.890 --> 00:00:49.000 if we can enhance certain memories over others. 00:00:49.040 --> 00:00:51.440 There was a paper recently in the journal "Science" 00:00:51.480 --> 00:00:53.720 by Ken Paller and his colleagues at Northwestern 00:00:53.760 --> 00:00:55.720 that seemed to show that this may be true, 00:00:55.760 --> 00:00:57.200 and that piqued our curiosity. 00:00:57.240 --> 00:00:59.640 Joud has been working on a DIY version of this task 00:00:59.680 --> 00:01:02.880 to see if we can improve memories through the use of sound in sleep. 00:01:02.920 --> 00:01:06.280 So Joud, how do you test if we can improve our memories with sleep? NOTE Paragraph 00:01:06.320 --> 00:01:07.760 Joud Mar’i: We need a human subject. NOTE Paragraph 00:01:08.760 --> 00:01:10.680 [Step 1: Play a game] 00:01:10.720 --> 00:01:13.320 We have a memory game that we have on an iPad, 00:01:13.360 --> 00:01:15.360 and then we make our subject play this game 00:01:15.400 --> 00:01:18.240 and remember the images and where they appear on the screen. NOTE Paragraph 00:01:18.280 --> 00:01:21.160 GG: So this is like a memory game you used to play as a child, 00:01:21.200 --> 00:01:22.440 which picture was where. 00:01:22.480 --> 00:01:25.320 And we tie each picture with a sound that represents it. NOTE Paragraph 00:01:25.360 --> 00:01:27.920 JM: So, if you can see a picture of a car, for example, 00:01:27.960 --> 00:01:29.600 and you would hear the car engine. NOTE Paragraph 00:01:29.640 --> 00:01:31.800 (Car engine starting) NOTE Paragraph 00:01:31.840 --> 00:01:34.440 GG: Just before you go to sleep we're going to test you. 00:01:34.480 --> 00:01:37.520 We're going to see how well you remember where the pictures are. 00:01:37.560 --> 00:01:40.520 Every time you see the picture, you're going to hear the sound. 00:01:40.560 --> 00:01:42.120 And now comes the experiment. 00:01:42.160 --> 00:01:43.620 You're going to go take a nap. 00:01:43.660 --> 00:01:44.650 [Step 2: Take a nap] 00:01:46.120 --> 00:01:49.360 And while you're sleeping, we're going to be recording your EEG. NOTE Paragraph 00:01:49.400 --> 00:01:52.960 JM: And then we wait for them to go into what's called the slow-wave sleep, 00:01:53.000 --> 00:01:56.920 which is the deepest phase of your sleep where it's really hard for you to wake up. NOTE Paragraph 00:01:56.960 --> 00:01:58.160 GG: OK, pause. 00:01:58.200 --> 00:02:00.000 So, here's some information on sleep. 00:02:00.040 --> 00:02:02.960 There are four stages: we have lighter stages of sleep and REM, 00:02:03.000 --> 00:02:05.600 but what we're interested in is called slow-wave sleep. 00:02:05.640 --> 00:02:07.880 And it gets its name from the electrical signals 00:02:07.920 --> 00:02:10.240 called Delta waves that we record from the brain. 00:02:10.280 --> 00:02:12.640 This is the part of sleep where scientists believe 00:02:12.680 --> 00:02:14.480 that memory consolidation can happen. 00:02:14.520 --> 00:02:15.920 In this deep period of sleep, 00:02:15.960 --> 00:02:19.080 we're going to do something that you don't know we're going to do. NOTE Paragraph 00:02:19.120 --> 00:02:22.410 JM: Here's where the tricky part comes, and we start playing our cues. NOTE Paragraph 00:02:23.000 --> 00:02:24.360 (Car engine starting) NOTE Paragraph 00:02:24.400 --> 00:02:25.840 GG: Do you play all the cues? NOTE Paragraph 00:02:25.880 --> 00:02:29.480 JM: No. We only want to play half of them to see if there's a difference. NOTE Paragraph 00:02:29.520 --> 00:02:30.880 GG: So your hypothesis is 00:02:30.920 --> 00:02:33.760 the one that they were listening to while they're sleeping 00:02:33.800 --> 00:02:35.240 they're going to do better at. NOTE Paragraph 00:02:35.280 --> 00:02:36.520 JM: Yes, exactly. NOTE Paragraph 00:02:37.920 --> 00:02:40.280 GG: When you wake back up and play the game again, 00:02:40.320 --> 00:02:43.400 do you do better or worse than before a nap? 00:02:43.440 --> 00:02:47.720 What we found is that if we played you a cue during your sleep, 00:02:47.760 --> 00:02:49.280 for example, a car -- 00:02:49.320 --> 00:02:51.360 You would remember the position of that car 00:02:51.400 --> 00:02:52.960 when you woke back up again. 00:02:53.000 --> 00:02:55.400 But if we didn't play you the cue during the sleep, 00:02:55.440 --> 00:02:57.000 for example, a guitar, 00:02:57.040 --> 00:03:00.280 you'd be less likely to remember that guitar when you woke up. 00:03:00.320 --> 00:03:03.120 The memories that were cued they remembered better 00:03:03.160 --> 00:03:04.480 than the ones they weren't, 00:03:04.520 --> 00:03:07.000 even though they don't remember hearing those sounds? NOTE Paragraph 00:03:07.040 --> 00:03:08.280 JM: Yes, we ask them. NOTE Paragraph 00:03:08.320 --> 00:03:11.240 GG: We know they're sleeping, they can't hear it, they wake up, 00:03:11.280 --> 00:03:13.840 they do better on those than the ones you didn't play. NOTE Paragraph 00:03:13.880 --> 00:03:15.680 GG: That's amazing. JM: It's like magic. NOTE Paragraph 00:03:15.720 --> 00:03:19.200 GG: Joud ran this experiment on 12 people and the results were significant. 00:03:19.240 --> 00:03:22.680 It's not that you remember things better; it's that you forget them less. 00:03:22.720 --> 00:03:26.560 I was a huge skeptic when I first heard that you could do better at a memory test 00:03:26.600 --> 00:03:28.320 just by playing sounds during sleep. 00:03:28.360 --> 00:03:30.080 But we replicated these experiments. 00:03:30.120 --> 00:03:33.440 The facts and memories we collect throughout the day are very fragile, 00:03:33.480 --> 00:03:35.360 and they are easily lost and forgotten. 00:03:35.400 --> 00:03:38.560 But by reactivating them during sleep, even without us being aware, 00:03:38.600 --> 00:03:42.080 it seems like we could make them more stable and less prone to forgetting. 00:03:42.120 --> 00:03:43.360 That's pretty incredible. 00:03:43.400 --> 00:03:45.640 Our brains are still active even when we're not. 00:03:45.680 --> 00:03:47.640 So if you're like me and a bit forgetful, 00:03:47.680 --> 00:03:51.400 perhaps a solution is a pair of headphones and a soft couch.