1 00:00:20,252 --> 00:00:23,852 Jane: This is But Why: A Podcast for Curious Kids, from Vermont 2 00:00:23,852 --> 00:00:27,557 Public. I'm Jane Lindholm. On this show, we take questions 3 00:00:27,557 --> 00:00:31,817 from curious kids all over the world, and we find answers. Have 4 00:00:31,817 --> 00:00:39,017 you ever...Have you ever...shoot, I forgot what I 5 00:00:39,017 --> 00:00:42,197 was gonna say! Good thing today's show is all about 6 00:00:42,197 --> 00:00:45,197 memory. We're going to talk with someone who can help us 7 00:00:45,197 --> 00:00:48,722 understand why we forget things and how we remember. 8 00:00:48,960 --> 00:00:52,380 Nick Turke-Brown: I study how the brain works and the magical 9 00:00:52,380 --> 00:00:57,000 things it does that help you learn and remember and make 10 00:00:57,000 --> 00:01:02,040 decisions and get along with your siblings and be creative, 11 00:01:02,340 --> 00:01:07,560 make art or music, have ideas and go about and grow into, you 12 00:01:07,560 --> 00:01:08,100 know, adults. 13 00:01:08,100 --> 00:01:12,120 Jane: That's Nick Turke-Brown. He's a professor of psychology 14 00:01:12,180 --> 00:01:16,605 at Yale University. Psychology is the study of how we think and 15 00:01:16,605 --> 00:01:20,205 behave and how our minds work. Professor Turke-Brown was 16 00:01:20,205 --> 00:01:23,925 excited to hear what kinds of questions you've sent us about 17 00:01:23,925 --> 00:01:26,505 memory. So let's get right to them. 18 00:01:26,745 --> 00:01:30,825 Brynn: Hello, I'm Brynn. I'm 11 years old, and I live in New 19 00:01:30,825 --> 00:01:33,705 Katie, Texas. How does memory work? 20 00:01:33,705 --> 00:01:37,950 Logan: Hi, I'm Logan. I'm six years old. I'm from [unclear]. 21 00:01:38,670 --> 00:01:40,950 How do humans remember stuff? 22 00:01:40,950 --> 00:01:45,750 Zeph: My name is Zeph, I'm six years old, and I live in Austin, 23 00:01:45,750 --> 00:01:48,510 Texas, and my question is, how do we remember things? 24 00:01:48,510 --> 00:01:54,990 Clara: I'm Clara and I'm five years old. I live in Oak Park, 25 00:01:55,110 --> 00:01:58,350 Illinois. How do you remember something? 26 00:01:58,710 --> 00:02:03,435 Noah: My name is Noah, and I'm three years old. I live in 27 00:02:03,495 --> 00:02:08,835 Sunnyvale, California. How do brains remember things? 28 00:02:08,835 --> 00:02:13,395 Nick Turke-Brown: Memory is basically your brain keeping a 29 00:02:13,395 --> 00:02:17,715 record of things that you experience. So when you see 30 00:02:17,715 --> 00:02:21,495 something or you hear something, or you go somewhere, that 31 00:02:21,555 --> 00:02:26,580 changes your brain, and your brain is able to then hold on to 32 00:02:26,580 --> 00:02:30,720 that experience and carry it forward in time until you get 33 00:02:30,720 --> 00:02:33,480 reminded of something, or you see something again, or you go 34 00:02:33,480 --> 00:02:38,340 back to the same place, and you're transported back to the 35 00:02:38,340 --> 00:02:41,280 last time you saw that thing, or you were in that place. And so 36 00:02:41,340 --> 00:02:47,385 basically it has to do with the effect of seeing or hearing or 37 00:02:47,385 --> 00:02:51,645 doing something on what's in your brain. And so your brain is 38 00:02:51,645 --> 00:02:54,105 like a recording device. You could think of it like a phone 39 00:02:54,105 --> 00:02:59,145 or a camera, but it's happening all the time without you trying. 40 00:02:59,265 --> 00:03:03,705 And it's really amazing how well it works. So that's essentially 41 00:03:03,765 --> 00:03:08,190 what's storing memories, is that when you have experiences, your 42 00:03:08,190 --> 00:03:08,970 brain changes. 43 00:03:09,140 --> 00:03:11,420 Jane: The really cool thing about that is there are 44 00:03:11,480 --> 00:03:15,200 different parts of the brain that store different things and 45 00:03:15,200 --> 00:03:17,840 help you form different types of memories. 46 00:03:17,960 --> 00:03:20,900 Nick Turke-Brown: Some parts of your brain remember when you 47 00:03:21,560 --> 00:03:25,100 learn how to ride a bike, you know that experience of falling 48 00:03:25,100 --> 00:03:28,760 off and then getting going and pedaling and moving fast, and 49 00:03:29,060 --> 00:03:33,125 that part of memory, you could think of it, what we might call 50 00:03:33,125 --> 00:03:37,925 motor memory, or how to do things, is supported by some 51 00:03:37,925 --> 00:03:40,325 parts of the brain. But there are other kinds of memories, 52 00:03:40,325 --> 00:03:44,585 too. You have preferences, like you like macaroni and cheese, or 53 00:03:44,585 --> 00:03:47,705 you like pizza. Those are preferences, things that you 54 00:03:47,705 --> 00:03:50,045 find rewarding or valuable. There are other parts of the 55 00:03:50,045 --> 00:03:52,385 brain that store those kinds of memories. When you eat something 56 00:03:52,385 --> 00:03:54,725 that you really like, or when you do an activity that you 57 00:03:54,725 --> 00:03:59,510 really enjoy. Then we have other kinds of memories that are, I 58 00:03:59,510 --> 00:04:03,590 think of as maybe what people normally refer to as memory, is 59 00:04:03,890 --> 00:04:08,330 like remembering a specific event. So I might remember going 60 00:04:08,330 --> 00:04:12,830 on a vacation or my last birthday party, or when I got 61 00:04:12,830 --> 00:04:18,995 grounded, or when I got my first, you know, tablet, or when 62 00:04:18,995 --> 00:04:22,355 I had some very memorable experience visiting a 63 00:04:22,355 --> 00:04:27,395 grandparent, those those events in our life, that's a different 64 00:04:27,395 --> 00:04:30,335 kind of memory, and that's supported by another part of the 65 00:04:30,335 --> 00:04:34,295 brain. And so that's kind of the answer is your brain is 66 00:04:34,715 --> 00:04:37,175 influenced by what you experience. Different parts of 67 00:04:37,175 --> 00:04:40,475 the brain are storing different parts of the experience. 68 00:04:40,535 --> 00:04:43,400 Jane: Not only are different parts of the brain involved in 69 00:04:43,400 --> 00:04:46,280 recording and saving those different types of thoughts or 70 00:04:46,280 --> 00:04:50,360 experiences, but there are a couple different stages when it 71 00:04:50,360 --> 00:04:54,800 comes to remembering them. The first one is that initial stage 72 00:04:54,800 --> 00:04:57,920 of thinking or feeling or experiencing something and kind 73 00:04:57,920 --> 00:04:59,900 of recording it in your brain. 74 00:05:00,080 --> 00:05:02,720 Nick Turke-Brown: That's what we call encoding. It's like the 75 00:05:02,720 --> 00:05:07,685 storage of the memory, but to make it stick, your brain sort 76 00:05:07,685 --> 00:05:11,285 of chews on it a little bit. It has to keep processing that 77 00:05:11,285 --> 00:05:14,405 information, and that's what happens during sleep. You think 78 00:05:14,405 --> 00:05:18,545 of dreaming as a kind of chewing on your memories, and what that 79 00:05:18,545 --> 00:05:22,985 does is it makes them more stable. It helps them stick 80 00:05:22,985 --> 00:05:26,285 around longer. So that's the second part. So you initially, 81 00:05:26,285 --> 00:05:29,270 you store the memory, or encode the memory, and then you 82 00:05:29,270 --> 00:05:33,050 consolidate the memory during sleep, and then the final part 83 00:05:33,050 --> 00:05:37,010 is retrieval. You have your next birthday party and you remember 84 00:05:37,010 --> 00:05:41,390 the last one, or you go to a place that you haven't been in a 85 00:05:41,390 --> 00:05:47,570 while and you remember that, or you remember some piece of 86 00:05:48,050 --> 00:05:49,002 information that somebody told you, or you remember how to do 87 00:05:49,002 --> 00:05:49,158 something, and you're accessing something that's been stored and 88 00:05:49,158 --> 00:05:51,575 consolidated in your brain. So that's what I would say what 89 00:05:51,575 --> 00:05:54,395 memory is, it's changes in your brain, different parts of your 90 00:05:54,395 --> 00:05:56,795 brain, and there's these different stages of encoding, 91 00:05:56,795 --> 00:05:58,475 consolidation and retrieval. 92 00:05:58,120 --> 00:06:00,160 Jane: You know, it's interesting. You mentioned 93 00:06:00,220 --> 00:06:04,180 something like our preferences, the things we like and dislike. 94 00:06:04,360 --> 00:06:08,560 And I hadn't thought of that as memory, but of course, it's tied 95 00:06:08,620 --> 00:06:12,340 to your experiences in the past. So something like, if you really 96 00:06:12,340 --> 00:06:16,540 like cheesecake, but then one time you have cheesecake, and 97 00:06:16,540 --> 00:06:20,740 then the next day you get the flu and you throw up the 98 00:06:20,740 --> 00:06:23,665 cheesecake, you're gonna remember that and you're gonna 99 00:06:23,665 --> 00:06:27,145 not like cheesecake anymore, even though maybe those two 100 00:06:27,145 --> 00:06:29,185 things actually didn't have anything to do with each other. 101 00:06:29,185 --> 00:06:31,885 Your brain makes an association, and that can change your 102 00:06:31,885 --> 00:06:35,305 preferences, which is, of course, tied to your experiences 103 00:06:35,305 --> 00:06:35,965 and memory. 104 00:06:36,085 --> 00:06:38,065 Nick Turke-Brown: Yeah, that's there's a name for that. It's 105 00:06:38,065 --> 00:06:41,365 called the Garcia Effect. So it might have been the cheesecake 106 00:06:41,365 --> 00:06:45,310 that made you feel sick, but because the cheesecake occurred 107 00:06:45,310 --> 00:06:49,210 before you got sick, it gets associated with that feeling of 108 00:06:49,210 --> 00:06:53,110 sickness, and then you afterwards, you might not be 109 00:06:53,110 --> 00:06:56,110 attracted to it as much, or like it as much, or you might want to 110 00:06:56,110 --> 00:06:59,290 avoid it. And so, yeah, that's a kind of memory. It's very fast 111 00:06:59,290 --> 00:07:06,939 memory. That only has to happen once, and then for the rest of 112 00:07:06,939 --> 00:07:06,996 your life, you might not like cheesecake anymore. 113 00:07:06,996 --> 00:07:07,025 Jane: What a bummer. 114 00:07:07,025 --> 00:07:07,039 Nick Turke-Brown: Yeah. 115 00:07:07,039 --> 00:07:09,055 Jane: Yeah, and then those ideas like learning how to ride a bike 116 00:07:09,055 --> 00:07:13,255 and remembering how to do it, or when you have something that you 117 00:07:13,255 --> 00:07:16,135 have to learn in science class and you're going to have a test 118 00:07:16,135 --> 00:07:19,255 about it and so you have to remember it. And often, we're 119 00:07:19,255 --> 00:07:23,875 told, if you're studying to learn something for a class, the 120 00:07:23,875 --> 00:07:27,115 best thing you can do is get a good night's sleep before your 121 00:07:27,115 --> 00:07:29,515 test. So that's what you're talking about, Nick, with the 122 00:07:29,515 --> 00:07:33,820 idea that your brain needs to get all of that stored in the 123 00:07:33,820 --> 00:07:38,260 right place so that you can pull it out when you need to retrieve 124 00:07:38,260 --> 00:07:41,620 it, or when you need to know that fact. So sleep really is 125 00:07:41,620 --> 00:07:43,180 important for learning and memory. 126 00:07:43,180 --> 00:07:46,540 Nick Turke-Brown: Definitely. People remember better, and they 127 00:07:47,140 --> 00:07:50,020 not only remember the details of what they learned before after 128 00:07:50,020 --> 00:07:55,165 sleep, but you're also able to use that experience in new ways, 129 00:07:55,165 --> 00:07:58,285 what's called generalization, taking something you learned 130 00:07:58,285 --> 00:08:01,225 before and applying it in a new setting. We do that in school 131 00:08:01,225 --> 00:08:05,005 all the time. You learn some concept about biology, and then 132 00:08:05,005 --> 00:08:08,545 you have to apply it in a new way, or you learn how to use a 133 00:08:08,545 --> 00:08:11,065 certain trick in math class, and now you have to use that to 134 00:08:11,065 --> 00:08:14,545 answer a new question that you haven't thought about before. So 135 00:08:14,545 --> 00:08:18,850 that ability to take memories and use them in new ways, that 136 00:08:18,850 --> 00:08:22,210 is the specific benefit of sleep, and you can see why 137 00:08:22,210 --> 00:08:23,830 that'd be really important for a test. 138 00:08:24,070 --> 00:08:28,450 Jane: We got a lot of kids who want to know why they can't 139 00:08:28,450 --> 00:08:31,450 remember things from when they were really little. 140 00:08:31,450 --> 00:08:35,110 Sage: Hi, my name is Sage. I'm eight years old. I live in Los 141 00:08:35,110 --> 00:08:39,190 Angeles, California. Why do we forget things that happened when 142 00:08:39,190 --> 00:08:40,510 we were babies? 143 00:08:40,510 --> 00:08:44,804 Lola: Hi, my name is Lola. I'm eight years old. I live in Palos 144 00:08:44,879 --> 00:08:49,475 Heights, Illinois. Why can't you remember stuff from when you 145 00:08:49,550 --> 00:08:50,455 were little? 146 00:08:50,440 --> 00:08:53,740 Iris: Hi, my name is Iris. I am nine years old, and I live in 147 00:08:53,740 --> 00:08:57,160 Melbourne, Australia. Why can't we remember when we were little? 148 00:08:57,400 --> 00:09:02,980 Julius: Hi, my name is Julius. I am seven, eight years old. I 149 00:09:02,980 --> 00:09:09,265 live in Ottawa, Ontario, Canada. Why do people forget things from 150 00:09:09,265 --> 00:09:10,225 when they're little? 151 00:09:10,240 --> 00:09:14,380 Natalie: Hi, my name is Natalie. I'm eight years old, and I live 152 00:09:14,380 --> 00:09:18,940 in netherford, New Jersey. Why can't we remember when we were 153 00:09:18,940 --> 00:09:19,780 babies? 154 00:09:19,780 --> 00:09:23,440 Archer and Maddie: My name is Archer, and I'm seven years old. 155 00:09:23,620 --> 00:09:27,940 And my name is Maddie, and I'm 10 years old. We live in 156 00:09:27,940 --> 00:09:33,100 Melbourne, Australia. Why can't we remember things from when 157 00:09:33,100 --> 00:09:33,940 we're little? 158 00:09:33,940 --> 00:09:38,485 Nick Turke-Brown: Yeah, this is what's known as infantile 159 00:09:38,545 --> 00:09:43,885 amnesia. So amnesia is a fancy word that means forgetting. 160 00:09:44,545 --> 00:09:47,365 Infantile means from the time that you were an infant or a 161 00:09:47,365 --> 00:09:52,765 baby. Generally, as older kids and adults, we don't remember 162 00:09:52,765 --> 00:09:56,665 much from the first few years of our lives. Usually, if you ask 163 00:09:56,665 --> 00:10:00,790 somebody, what's your first memory, if they're old enough, 164 00:10:00,790 --> 00:10:04,030 they'll they'll generally say, you know, somewhere between four 165 00:10:04,030 --> 00:10:07,630 and seven years old. Now, if you're a five year old, you 166 00:10:07,630 --> 00:10:10,630 might remember something from when you were two or three, but 167 00:10:10,630 --> 00:10:13,090 by the time you're seven or eight or nine, that's going to 168 00:10:13,090 --> 00:10:17,770 be gone. So why? It's a deep scientific mystery. It's one of 169 00:10:17,770 --> 00:10:22,435 the topics that my lab at Yale University works on. We study 170 00:10:22,795 --> 00:10:25,555 what's happening in the brains of babies and toddlers as 171 00:10:25,555 --> 00:10:28,375 they're forming memories. And so we're trying to figure out why 172 00:10:28,375 --> 00:10:31,735 it is that we don't remember what happened during that time. 173 00:10:31,000 --> 00:10:35,260 Now, I think it's important to say it's not just that time 174 00:10:35,260 --> 00:10:38,980 passes and we forget things. So it's not just that, you know, 175 00:10:38,980 --> 00:10:41,140 that was a long time ago when you were a baby and so of 176 00:10:41,140 --> 00:10:43,660 course, you forget it. Because later on in life, you're going 177 00:10:43,660 --> 00:10:46,600 to remember things from a long time ago, you know, from when 178 00:10:46,600 --> 00:10:51,100 you're 10 years old or 20 years old, but there's a specific time 179 00:10:51,100 --> 00:10:53,740 when you're sort of zero to four years old where you don't 180 00:10:53,740 --> 00:10:56,785 remember very much. So we're talking before about how there's 181 00:10:56,785 --> 00:11:00,925 different stages of memory, like there's the encoding, the 182 00:11:00,925 --> 00:11:04,345 storage part of the memory, there's the consolidation, and 183 00:11:04,345 --> 00:11:07,825 then there's the retrieval, like accessing the memory. And so 184 00:11:07,885 --> 00:11:10,585 each of those stages is a possible point at which you 185 00:11:10,585 --> 00:11:14,485 might have a failure, when you're really young, and be 186 00:11:14,485 --> 00:11:19,330 unable to kind of access those memories. So is it that babies 187 00:11:19,330 --> 00:11:22,870 don't store memories, so there's nothing to retrieve later on 188 00:11:22,870 --> 00:11:25,570 because you didn't store a memory in the first place? Or do 189 00:11:25,570 --> 00:11:30,250 they store them fine, but later in life, we just can't access 190 00:11:30,250 --> 00:11:33,370 them for some reason, we can't retrieve them? And so our 191 00:11:33,370 --> 00:11:36,850 research suggests that starting around 12 months, so around one 192 00:11:36,850 --> 00:11:41,215 year old, babies are able to start storing memories in their 193 00:11:41,215 --> 00:11:45,055 brain. And this is much earlier than people's first memories, so 194 00:11:45,055 --> 00:11:48,055 it suggests that there are memories being stored by around 195 00:11:48,055 --> 00:11:52,195 one year of age, and we lose access to them later on. And so 196 00:11:52,195 --> 00:11:55,015 we're trying to figure out why is it that we can't access those 197 00:11:55,015 --> 00:11:58,195 memories? And there's the there's the sort of science 198 00:11:58,195 --> 00:12:02,575 fiction possibility that we still have those memories in our 199 00:12:02,575 --> 00:12:05,620 brain from when we were babies, and we just can't get back to 200 00:12:05,620 --> 00:12:08,800 them using the normal way. And so maybe there are, you know, 201 00:12:08,800 --> 00:12:12,100 tricks we could use to remember things from earlier in our life. 202 00:12:12,100 --> 00:12:16,180 Jane: You know, if you spend time with a very young kid, if 203 00:12:16,180 --> 00:12:20,980 maybe you have a little sibling who's one or two, you might be 204 00:12:20,980 --> 00:12:25,180 aware that they seem to have really great memories, because 205 00:12:25,240 --> 00:12:29,185 you might have a two year old brother or sister who every time 206 00:12:29,185 --> 00:12:33,325 they pass one street, they just say "Bird!" because you saw a 207 00:12:33,325 --> 00:12:37,285 goose there once, and you would forget that there was a goose 208 00:12:37,285 --> 00:12:40,105 there one time, because it either wasn't a very important 209 00:12:40,105 --> 00:12:42,205 moment, or you've got a lot of other things you're trying to 210 00:12:42,205 --> 00:12:46,225 remember, but that toddler remembers that one little 211 00:12:46,225 --> 00:12:49,825 detail. It sometimes seems like toddlers have really great 212 00:12:49,825 --> 00:12:50,185 memories. 213 00:12:50,000 --> 00:12:52,160 Nick Turke-Brown: Yeah, I think that's right. That's part of the 214 00:12:52,160 --> 00:12:55,460 reason we started studying this. How is it that as adults, we 215 00:12:55,460 --> 00:12:58,820 don't remember anything for that period, and yet, young kids 216 00:12:58,820 --> 00:13:03,200 often have, like, pretty good memories?They remember a person 217 00:13:03,200 --> 00:13:06,500 that they met, or a magician they saw at the at the park, or 218 00:13:06,500 --> 00:13:09,920 a song that they love, or they remember that after this turn in 219 00:13:09,920 --> 00:13:13,280 the road you get to their daycare, or you remember some 220 00:13:13,340 --> 00:13:18,725 little toy you know that they got on Halloween. So I think 221 00:13:18,725 --> 00:13:23,225 that infants and toddlers have memory, and for whatever reason, 222 00:13:23,225 --> 00:13:26,045 those memories don't stick around, and they might still be 223 00:13:26,045 --> 00:13:29,825 there and just inaccessible, or they might get lost with the 224 00:13:29,825 --> 00:13:32,885 passage of time, but that's what we're working on. It's 225 00:13:32,885 --> 00:13:37,910 definitely true that kids, especially babies and toddlers, 226 00:13:38,090 --> 00:13:41,630 are learning a tremendous amount. We talked about learning 227 00:13:41,630 --> 00:13:46,730 how to ride a bike or developing food preferences. That's all 228 00:13:46,730 --> 00:13:49,910 happening in the first couple years of life. If you think 229 00:13:49,910 --> 00:13:54,950 about learning language, every baby who's brought up in a home 230 00:13:54,950 --> 00:13:58,430 where they hear a language learns that language without 231 00:13:58,430 --> 00:14:00,935 really trying, and actually, they learn it much better than 232 00:14:00,935 --> 00:14:04,895 an adult or an older kid can learn that language. We're 233 00:14:04,895 --> 00:14:08,795 really, really good at learning early in life. We learn how to 234 00:14:08,795 --> 00:14:13,175 walk. We learn about relationships with siblings and 235 00:14:13,175 --> 00:14:16,235 with parents. We learn about food. We learn about our home 236 00:14:16,235 --> 00:14:20,255 environment. We learn the names of objects. So infancy is an 237 00:14:20,255 --> 00:14:23,960 incredible period of learning, and that makes it even more 238 00:14:23,960 --> 00:14:26,600 mysterious why we don't remember anything from that time. 239 00:14:27,080 --> 00:14:31,100 Bennett: I am Bennett. I live in Sammamish, Washington, and I 240 00:14:31,100 --> 00:14:35,540 want to know how and why do brains forget. 241 00:14:35,540 --> 00:14:41,420 Mac: My name is Mac. I'm six. I'm from Indianapolis. Why do we 242 00:14:41,420 --> 00:14:42,020 forget? 243 00:14:42,000 --> 00:14:48,960 Clara: Hello. My name is Clara. I am six years old. I am from 244 00:14:48,960 --> 00:14:54,600 Superior, Colorado, and my question is why do people forget 245 00:14:54,600 --> 00:14:55,140 things? 246 00:14:55,140 --> 00:14:58,920 Nick Turke-Brown: Forgetting is sometimes frustrating, like 247 00:14:58,920 --> 00:15:01,980 you're trying to find a toy or you're trying to remember 248 00:15:01,980 --> 00:15:06,180 somebody's name, but a lot of the time, forgetting is not such 249 00:15:06,225 --> 00:15:11,865 a bad thing. Memory is limited, and forgetting helps clean up 250 00:15:11,865 --> 00:15:15,885 our memories. So when you try to remember something, it might be 251 00:15:15,885 --> 00:15:18,405 hard to access it, and that's because a lot of other memories 252 00:15:18,405 --> 00:15:21,105 are coming to mind. You might be trying to remember one thing and 253 00:15:21,165 --> 00:15:23,325 you're remembering other unrelated things, and that's 254 00:15:23,325 --> 00:15:26,925 called interference. So part of the reason we forget things is 255 00:15:26,925 --> 00:15:31,290 because other unrelated memories are coming to mind and 256 00:15:31,290 --> 00:15:35,310 distracting us or confusing us. So forgetting is a way of, kind 257 00:15:35,310 --> 00:15:38,310 of cleaning up memory and removing or reducing 258 00:15:38,310 --> 00:15:43,950 interference. And we think of forgetting as bad, but I want to 259 00:15:44,670 --> 00:15:47,250 emphasize that some forgetting is good, and it makes your 260 00:15:47,250 --> 00:15:50,730 overall memory better. It makes it better able to remember the 261 00:15:50,730 --> 00:15:51,870 most important things. 262 00:15:51,870 --> 00:15:56,835 Jane: So forgetting isn't all bad news, but it can also be so 263 00:15:56,955 --> 00:15:59,415 inconvenient when it happens. 264 00:15:59,655 --> 00:16:03,795 Ella: Hi. My name is Ella. I am seven years old. I'm from 265 00:16:03,795 --> 00:16:07,935 Bannockburn in New Zealand, and I would like to know why do we 266 00:16:07,935 --> 00:16:13,395 forget what we are going to say while we are waiting for our 267 00:16:13,395 --> 00:16:15,240 turn to speak? 268 00:16:15,240 --> 00:16:17,880 Nick Turke-Brown: Yeah, so I think there's a lot of the kinds 269 00:16:17,880 --> 00:16:20,520 of memory we've been talking about: remembering a birthday 270 00:16:20,520 --> 00:16:25,020 party or how to ride a bike, or facts that you learn in class, I 271 00:16:25,020 --> 00:16:28,740 would call those with long term memory, memories that stick 272 00:16:28,740 --> 00:16:32,340 around a long time. There's another kind of memory, called 273 00:16:32,340 --> 00:16:36,120 short term memory, which refers to holding on to information in 274 00:16:36,120 --> 00:16:39,705 our mind for a short period of time. So if you're in class and 275 00:16:40,125 --> 00:16:43,485 you're waiting to ask a question, you might have thought 276 00:16:43,485 --> 00:16:45,525 about this question. You're waiting your turn, and you have 277 00:16:45,525 --> 00:16:48,405 your hand up, and you're holding that question in your mind, and 278 00:16:48,945 --> 00:16:52,545 then you get called on and you can't remember what you wanted 279 00:16:52,545 --> 00:16:56,325 to say. That's a failure of short term memory. And what 280 00:16:56,325 --> 00:16:58,845 happens in short term memory is that in order to keep that 281 00:16:58,845 --> 00:17:01,830 memory alive, you have to actively think about it; you 282 00:17:01,830 --> 00:17:05,190 have to focus on it. And so anything that happens that might 283 00:17:05,190 --> 00:17:08,490 distract your attention--somebody else asking 284 00:17:08,490 --> 00:17:12,330 a question that you think is interesting, or, you know, I 285 00:17:12,330 --> 00:17:17,730 don't know, a siren that passes on the street, or maybe some 286 00:17:17,730 --> 00:17:20,070 other question that comes to mind in response to what 287 00:17:20,070 --> 00:17:23,670 somebody else is talking about, that could distract you. And 288 00:17:23,670 --> 00:17:27,495 when you get distracted, you lose your grip on that short 289 00:17:27,495 --> 00:17:30,735 term memory that you had in mind. So in that situation, it's 290 00:17:30,735 --> 00:17:34,455 probably about distraction. Those kinds of short term 291 00:17:34,455 --> 00:17:37,995 memories also just get weaker over time. So if you're 292 00:17:37,995 --> 00:17:40,395 rehearsing something in your mind, you're holding on to some 293 00:17:40,395 --> 00:17:42,855 information, the longer you have to do that, the more likely you 294 00:17:42,855 --> 00:17:43,575 are to forget it. 295 00:17:43,000 --> 00:17:47,380 Jane: We were talking earlier about how important sleep is to 296 00:17:47,380 --> 00:17:50,080 memory, but Claire is wondering, 297 00:17:50,080 --> 00:17:53,260 Claire: Why do we not remember things we say in the middle of 298 00:17:53,260 --> 00:17:57,820 the night when we say we want to remember them in the morning? 299 00:17:57,820 --> 00:18:00,940 Jane: And is it the same thing if, let's say you fall asleep in 300 00:18:00,940 --> 00:18:04,180 the car, and your adult wakes you up to go to your bed, and 301 00:18:04,180 --> 00:18:06,760 you say something, and then the next morning, they say, do you 302 00:18:06,805 --> 00:18:09,625 remember that silly thing you said when I was carrying you 303 00:18:09,625 --> 00:18:13,045 back to your bed? And you're like, No, I don't remember that! 304 00:18:13,045 --> 00:18:14,785 Same type of thing? 305 00:18:14,785 --> 00:18:17,065 Nick Turke-Brown: Yeah, it's probably similar. If you're less 306 00:18:17,065 --> 00:18:19,705 awake, it's very hard to pay attention when you're dozing 307 00:18:19,705 --> 00:18:22,765 off. So it might be you're also just not storing memories very 308 00:18:22,765 --> 00:18:23,665 well at that point. 309 00:18:23,665 --> 00:18:27,085 Jane: It's fascinating to think about how our brains are hard at 310 00:18:27,085 --> 00:18:30,610 work while we're both awake and while we're asleep, even though 311 00:18:30,610 --> 00:18:33,310 we're not necessarily aware of all that work our brains are 312 00:18:33,310 --> 00:18:37,030 doing to consolidate, store, retrieve and even remove 313 00:18:37,030 --> 00:18:42,010 memories. After the break: why are some people forgetful, and 314 00:18:42,010 --> 00:18:44,830 do elephants really never forget? 315 00:18:44,830 --> 00:18:47,590 BREAK: BREAK 316 00:18:47,540 --> 00:18:50,600 Jane: This is But Why! I'm Jane Lindholm, and today we're 317 00:18:50,600 --> 00:18:54,440 learning about how our brains remember things with Professor 318 00:18:54,440 --> 00:18:57,020 Nick Turke-Brown of Yale University. 319 00:18:57,380 --> 00:19:01,220 Ava: Hello. My name is Ava. I'm nine years old. I'm from 320 00:19:01,220 --> 00:19:04,520 Peterborough, England. Why are some people forgetful? 321 00:19:05,480 --> 00:19:08,240 Nick Turke-Brown: Yeah, you know, some people have better 322 00:19:08,240 --> 00:19:12,965 memories. Some people have worse memories. Even within what you 323 00:19:12,965 --> 00:19:17,345 would expect of healthy you know, typical kids and adults, 324 00:19:17,705 --> 00:19:21,545 there are people who are more forgetful than others. There's 325 00:19:21,545 --> 00:19:24,065 even people who have really amazing memories, you know, 326 00:19:24,065 --> 00:19:29,405 better memories than everybody else in general. But all of this 327 00:19:29,405 --> 00:19:32,825 is pretty normal, like even people who you would think of as 328 00:19:32,825 --> 00:19:37,370 forgetful, are still healthy and remember what they need to 329 00:19:37,370 --> 00:19:43,310 remember to do well. There are people who have worse memories 330 00:19:43,310 --> 00:19:46,850 because of medical conditions, like if they have something 331 00:19:46,850 --> 00:19:51,590 called mild cognitive impairment or dementia, or you might have 332 00:19:51,590 --> 00:19:55,370 heard of Alzheimer's disease. These are medical conditions 333 00:19:55,370 --> 00:19:58,235 that make memory much worse, where you forget loved ones, 334 00:19:58,235 --> 00:20:03,155 even. But within the healthy kind of typically developing 335 00:20:03,155 --> 00:20:07,235 population, there's variation, but it's all pretty normal and 336 00:20:07,295 --> 00:20:11,195 to be expected. And again, remembering more is not always 337 00:20:11,255 --> 00:20:14,915 better. What you would want to remember is the important 338 00:20:14,915 --> 00:20:15,995 things, not everything. 339 00:20:15,995 --> 00:20:20,315 Tyce: Hi, I'm Tice. I am nine years old. I live in Bluffdale, 340 00:20:20,360 --> 00:20:23,780 Utah. Why do we forget things? And what does our brain do with 341 00:20:23,780 --> 00:20:25,100 the things we forget? 342 00:20:27,220 --> 00:20:29,860 Nick Turke-Brown: Well, there's lots of different reasons you 343 00:20:29,860 --> 00:20:35,440 can forget. Like, the memories can be sort of erased. How 344 00:20:35,440 --> 00:20:39,580 memories are stored in the brain is through cells in the brain 345 00:20:39,580 --> 00:20:42,460 called neurons. These are like cells in the rest of your body, 346 00:20:42,460 --> 00:20:46,900 but neurons are cells in your brain, and they they connect 347 00:20:46,900 --> 00:20:50,425 with one another. They touch each other. And how they connect 348 00:20:50,425 --> 00:20:53,065 with one another is how memories are stored. Those are called 349 00:20:53,065 --> 00:20:57,265 synapses. Those are how two cells talk to each other, and 350 00:20:57,265 --> 00:21:00,505 the pattern of how cells are connected to each other is how 351 00:21:00,505 --> 00:21:03,145 memories are stored. This is different from our computer 352 00:21:03,145 --> 00:21:06,985 stores, you know, a file or a photo, but our brains store 353 00:21:06,985 --> 00:21:09,625 memory is that way. And so if you lose those connections, 354 00:21:09,625 --> 00:21:14,110 either the cells themselves die, sometimes over time, or you lose 355 00:21:14,110 --> 00:21:18,610 some of the connections break down, or the brain region grows 356 00:21:18,610 --> 00:21:22,210 or changes in its composition, those memories can essentially 357 00:21:22,210 --> 00:21:26,410 get get erased so that they're gone. That's one kind of change 358 00:21:26,410 --> 00:21:29,890 that happens in the brain. That was one of the theories of 359 00:21:30,310 --> 00:21:33,430 infantile amnesia that we were talking about before, is that as 360 00:21:33,430 --> 00:21:36,115 you get older, and that sort of three to four year old range, 361 00:21:36,295 --> 00:21:39,115 you have a lot of new cells in your parts your brain that store 362 00:21:39,115 --> 00:21:41,875 memories, and they might be overwriting memories that you 363 00:21:41,875 --> 00:21:44,695 already have in there. That's called neurogenesis, like the 364 00:21:44,695 --> 00:21:48,415 birth of new neurons. So that's one kind of erasing. 365 00:21:49,020 --> 00:21:51,720 Another kind of forgetting that happens in the brain is when 366 00:21:52,380 --> 00:21:56,820 there's a disconnect between how the memory is stored and then 367 00:21:56,820 --> 00:22:00,240 how you access it. So you might have some cells that are 368 00:22:00,240 --> 00:22:02,940 connected in the brain through synapses in a certain way that 369 00:22:02,940 --> 00:22:07,440 stores a memory. But if, when you see a familiar person or you 370 00:22:07,500 --> 00:22:11,100 go to a familiar place, it doesn't get matched to that 371 00:22:11,100 --> 00:22:14,445 memory, you're not going to be able to call it to mind and 372 00:22:14,445 --> 00:22:17,205 retrieve it and remember that earlier experience. So it's not 373 00:22:17,205 --> 00:22:21,945 that the memory itself is gone, it's that you can't get it. It's 374 00:22:21,945 --> 00:22:26,505 like if you have a book and you can't find your book, right, you 375 00:22:26,505 --> 00:22:29,385 know you have the book you might look on your bookshelf and you 376 00:22:29,385 --> 00:22:32,805 just can't find it. So you can't read what's inside it. It's that 377 00:22:32,805 --> 00:22:35,190 kind of an issue. The book still exists. It's just under your bed 378 00:22:35,190 --> 00:22:37,770 or somewhere else. You just can't get to it. And so that's 379 00:22:37,770 --> 00:22:41,250 another reason why we forget a change that happens in the brain 380 00:22:41,250 --> 00:22:45,210 is that the cues, the things in the world that remind us of 381 00:22:45,210 --> 00:22:49,590 things, just don't map onto or can't be used to access the 382 00:22:49,590 --> 00:22:54,630 memory. And for example, when you meet somebody you know at 383 00:22:54,630 --> 00:22:59,055 the park or at school, you don't just remember that person's face 384 00:22:59,055 --> 00:23:02,955 or their name. You link that person to the place that they're 385 00:23:02,955 --> 00:23:07,515 in. So you remember that you met this kid on the playground, and 386 00:23:07,515 --> 00:23:11,775 if you see that same friend at the grocery store, you might not 387 00:23:11,775 --> 00:23:14,535 even recognize them, because that's not where you saw them 388 00:23:14,535 --> 00:23:18,435 the first time. So memories are stored in what's called a 389 00:23:18,435 --> 00:23:22,440 context, in a place, in a situation. And so a lot of 390 00:23:22,440 --> 00:23:25,680 forgetting occurs because we're not in the right context. You go 391 00:23:25,680 --> 00:23:30,300 to the grocery store, you're not expecting to see a friend that 392 00:23:30,300 --> 00:23:33,000 you just met on the playground, and so it's harder to recognize 393 00:23:33,000 --> 00:23:36,840 them. And so a lot of forgetting happens when we're just not in 394 00:23:36,840 --> 00:23:39,600 the right mindset in order to access a memory. 395 00:23:39,600 --> 00:23:42,420 Jane: We have just a couple more questions. One is from Poppy, 396 00:23:42,660 --> 00:23:43,965 who wonders... 397 00:23:43,965 --> 00:23:48,525 Poppy: Why, when you bump your head hard on something hard, you 398 00:23:48,525 --> 00:23:49,965 lose your memory? 399 00:23:49,965 --> 00:23:54,105 Nick Turke-Brown: Yeah. Hopefully Poppy's not bumping 400 00:23:54,105 --> 00:23:58,005 their head a lot like this, because it's, it's usually not a 401 00:23:58,005 --> 00:24:02,265 great sign if you have an accident, or you fall off your 402 00:24:02,265 --> 00:24:06,111 bike, or you fall down on the playground and you bump your 403 00:24:06,111 --> 00:24:07,290 head and you can't remember something, you definitely should 404 00:24:07,290 --> 00:24:13,410 tell a parent or and maybe go see a doctor. That can be a sign 405 00:24:13,410 --> 00:24:18,210 of a concussion or sometimes called a traumatic brain injury, 406 00:24:18,270 --> 00:24:24,870 TBI. So that's not a common thing, hopefully, to bump your 407 00:24:24,870 --> 00:24:27,630 head in a way that would make you forget. But it is the case 408 00:24:27,630 --> 00:24:30,675 that when people get in accidents like a car accident or 409 00:24:30,675 --> 00:24:35,895 a bicycle accident, or fall on a playground, that can cause 410 00:24:36,135 --> 00:24:40,455 either temporary or longer lasting damage to the brain. It 411 00:24:40,455 --> 00:24:44,175 could be that in the moment, you know you're playing with your 412 00:24:44,175 --> 00:24:46,515 friends, and you fall and then you can't remember what you were 413 00:24:46,515 --> 00:24:52,680 just doing a moment ago. That could be because you maybe you 414 00:24:52,680 --> 00:24:55,200 lose consciousness, or maybe you're in a lot of pain, and you 415 00:24:55,200 --> 00:24:58,380 sort of forget what you were doing. So that that would be a 416 00:24:58,440 --> 00:25:01,620 less scary version of this. But if you had a more significant 417 00:25:01,620 --> 00:25:05,160 accident that caused brain damage, that can cause damage to 418 00:25:05,160 --> 00:25:08,520 parts of your brain that are really important for memory, and 419 00:25:08,520 --> 00:25:13,380 so it's not unusual in cases of bad accidents like that, to 420 00:25:13,380 --> 00:25:16,080 damage some of the parts of the brain that are important for 421 00:25:16,080 --> 00:25:18,525 memory, or some of the connections in the brain that 422 00:25:18,525 --> 00:25:22,665 help you to take a memory and then act on it. So I would think 423 00:25:22,665 --> 00:25:25,785 of that as, hopefully, a rare event, but it is a real 424 00:25:25,845 --> 00:25:28,785 consequence of accidents that people have problems with 425 00:25:28,785 --> 00:25:29,205 memory. 426 00:25:29,360 --> 00:25:35,780 Annika: My name is Annika, and I'm five years old, and I live 427 00:25:36,080 --> 00:25:40,460 in Chicago, Illinois. How do grownups remember everything? 428 00:25:40,460 --> 00:25:43,400 Nick Turke-Brown: Well, the good news for Annika is that grown 429 00:25:43,400 --> 00:25:44,960 ups do not remember everything. 430 00:25:46,100 --> 00:25:47,480 Jane: I can say that's true. 431 00:25:47,480 --> 00:25:50,480 Nick Turke-Brown: I can say that as a grown up, but it sometimes 432 00:25:50,480 --> 00:25:52,025 feels like that when you're talking with your parents, 433 00:25:52,025 --> 00:25:55,325 they're like, know it alls or have all the they have all the 434 00:25:55,325 --> 00:25:57,065 answers when you ask them a question. 435 00:25:57,065 --> 00:25:59,585 Jane: Or they remember, I told you to clean your room 436 00:25:59,585 --> 00:26:00,125 yesterday. 437 00:26:00,000 --> 00:26:03,900 Nick Turke-Brown: They remember some deal they made with you. 438 00:26:05,100 --> 00:26:08,100 But the answer is that grown ups don't remember everything. 439 00:26:08,400 --> 00:26:13,680 Adults and kids, we store some memories, but not everything. It 440 00:26:13,680 --> 00:26:17,400 is also the case so that adults have more experiences. So if you 441 00:26:17,400 --> 00:26:19,680 think of what we were talking about before as memory being 442 00:26:19,680 --> 00:26:22,320 about, you have some experience, you're doing something, and your 443 00:26:22,320 --> 00:26:26,445 brain is plastic. It's like Play Doh, it's being molded based on 444 00:26:26,445 --> 00:26:30,285 your experience. Adults just have more of that. You know, 445 00:26:30,645 --> 00:26:33,705 they've gone through school, they might have a job, they have 446 00:26:33,705 --> 00:26:36,285 a family, they have some skills, they have a lot of 447 00:26:36,285 --> 00:26:41,085 responsibilities. So they've gained knowledge over time, and 448 00:26:41,085 --> 00:26:44,685 they can use that knowledge to answer questions or even to 449 00:26:44,685 --> 00:26:47,130 store memories better. The more you know about the world, the 450 00:26:47,130 --> 00:26:49,710 easier it is to store memories, because you're taking things you 451 00:26:49,710 --> 00:26:53,670 already know and recombining them in new ways. So it is the 452 00:26:53,670 --> 00:26:57,270 case that adults have more knowledge. That's a kind of 453 00:26:57,270 --> 00:26:59,670 memory. It's often called semantic memory, memory for 454 00:26:59,670 --> 00:27:03,270 facts or details. That is something that increases over 455 00:27:03,270 --> 00:27:06,570 your lifespan as you have more and more experiences, as you 456 00:27:06,570 --> 00:27:10,050 spend longer in school, and as you you know, learn new things. 457 00:27:10,290 --> 00:27:12,795 So adults do have more of that, but I wouldn't say that they 458 00:27:12,795 --> 00:27:16,515 remember all of the events or experiences that they've had in 459 00:27:16,515 --> 00:27:18,975 life any better than than an older child would. 460 00:27:19,035 --> 00:27:22,395 Eva: My name is Eva. I am eight years old. I live in Dayton, 461 00:27:22,395 --> 00:27:26,955 Ohio, and my question is, how do elephants remember everything? 462 00:27:27,440 --> 00:27:29,060 Nick Turke-Brown: Yeah, it's really interesting. You know, 463 00:27:29,120 --> 00:27:33,260 elephants have good social memories for other elephants. 464 00:27:33,260 --> 00:27:36,680 They have good memories for navigation routes. So they kind 465 00:27:36,680 --> 00:27:39,320 of move a lot through their through their environment, and 466 00:27:39,320 --> 00:27:42,020 they can remember different locations in their environment 467 00:27:42,020 --> 00:27:46,160 well. They have an interesting social group dynamics, and so 468 00:27:46,160 --> 00:27:50,345 they remember about how other elephants are behaving. And so 469 00:27:50,405 --> 00:27:53,465 they do have good memories, but I don't think they're 470 00:27:53,645 --> 00:28:00,485 exceptional. Most large animals and even a lot of small animals 471 00:28:00,485 --> 00:28:05,705 have great memories. It's really important to survive in the 472 00:28:05,705 --> 00:28:11,045 natural world, to learn from trial and error, to learn from 473 00:28:11,045 --> 00:28:15,830 experience, to learn what's safe and what's not safe, or who's 474 00:28:16,250 --> 00:28:22,850 kind and who's unkind. Evolution has endowed our brains with the 475 00:28:22,850 --> 00:28:26,510 ability to store memories, and that's true of almost all 476 00:28:26,510 --> 00:28:33,050 species. In animals like mammals, we have brains that are 477 00:28:33,050 --> 00:28:35,990 really evolved, that have certain parts of the brain, like 478 00:28:36,410 --> 00:28:39,515 a region called the hippocampus. It's like a hippopotamus, but 479 00:28:39,515 --> 00:28:45,695 hippo-campus. And that brain region is in mice, in elephants, 480 00:28:45,695 --> 00:28:48,635 in humans, and it stores memories in all of those 481 00:28:48,935 --> 00:28:53,375 animals. So animals vary a lot in what kinds of things they 482 00:28:53,375 --> 00:28:57,875 remember. You know, mice might remember how things smell. Dogs 483 00:28:57,875 --> 00:29:00,920 might remember how things smell better than humans. Elephants 484 00:29:00,920 --> 00:29:03,860 might remember large environments better because they 485 00:29:03,980 --> 00:29:07,340 move a lot. So there are different kinds of knowledge or 486 00:29:07,340 --> 00:29:10,700 memories that different animals need in order to survive and 487 00:29:10,700 --> 00:29:14,000 thrive in their niche, and humans have that too. So 488 00:29:14,000 --> 00:29:18,080 elephants, there's kind of the sense that elephants have great 489 00:29:18,080 --> 00:29:20,540 memories. They do have large brains. They do have some of 490 00:29:20,660 --> 00:29:23,525 these brain structures that are really important for memory are 491 00:29:23,525 --> 00:29:26,885 large in elephants, and so they probably do have great memories, 492 00:29:26,885 --> 00:29:31,805 but so do so do sea lions, so do humans, so do mice, and without 493 00:29:31,805 --> 00:29:34,565 that, we wouldn't be able to learn from our mistakes. We 494 00:29:34,565 --> 00:29:37,325 wouldn't be able to make predictions about what's going 495 00:29:37,325 --> 00:29:40,025 to happen in a new scenario. We wouldn't be able to build 496 00:29:40,025 --> 00:29:44,285 relationships with other animals or humans. So memory is really 497 00:29:44,285 --> 00:29:48,830 the core of who we are, and without memory, you lose a bit 498 00:29:48,830 --> 00:29:51,470 of your own identity, your own personality. 499 00:29:51,900 --> 00:29:54,900 Jane: And don't forget your brain is storing memories all 500 00:29:54,900 --> 00:29:57,900 the time, not just when you're trying really hard to memorize 501 00:29:57,900 --> 00:30:01,260 something. That includes right now. What do you think you're 502 00:30:01,260 --> 00:30:05,400 going to remember from this episode? Thanks to Dr Nick 503 00:30:05,400 --> 00:30:08,820 Turke-Brown of Yale University for helping us understand how we 504 00:30:08,820 --> 00:30:12,420 remember and how we forget things. He has his own lab where 505 00:30:12,420 --> 00:30:16,725 he studies memory. As always, if you have a question about 506 00:30:16,725 --> 00:30:20,385 anything, have an adult record, you asking it on a smartphone 507 00:30:20,445 --> 00:30:24,105 using an app like Voice Memos. Then have your adult email the 508 00:30:24,105 --> 00:30:26,325 file to questions@butwhykids.org. But 509 00:30:26,325 --> 00:30:32,625 Why is produced by Sarah Baik, Melody Bodette and me, Jane 510 00:30:32,625 --> 00:30:37,470 Lindholm, at Vermont Public and distributed by PRX. Our video 511 00:30:37,470 --> 00:30:40,530 producer is Joey Palumbo, and our theme music is by Luke 512 00:30:40,530 --> 00:30:44,070 Reynolds, if you like our show, please have your adults help you 513 00:30:44,070 --> 00:30:48,090 give us a thumbs up or a review on whatever podcast platform you 514 00:30:48,090 --> 00:30:51,690 use to listen to us, it helps other kids and families find us. 515 00:30:52,410 --> 00:30:57,030 We'll be back in two weeks with an all new episode. Until then, 516 00:30:57,330 --> 00:30:58,890 stay curious!