WEBVTT - Why Do Humans Dream? 0:00:02.040 --> 0:00:07.160 Welcome to brain stuff. From how stuff Works, Hey, brain Stuff, 0:00:07.200 --> 0:00:10.200 Loring Vogel Bomb. Here the human brain is a mysterious 0:00:10.200 --> 0:00:13.280 little ball of gray matter. After all these years, researchers 0:00:13.280 --> 0:00:15.840 are still baffled by many aspects of how and why 0:00:15.880 --> 0:00:19.200 it operates like it does. Scientists have been performing sleep 0:00:19.200 --> 0:00:21.760 and dream studies for decades now, and we still aren't 0:00:21.800 --> 0:00:24.360 a hundred percent sure about the function of sleep or 0:00:24.400 --> 0:00:27.479 exactly how and why we dream. We do know that 0:00:27.520 --> 0:00:30.320 our dream cycle is typically most abundant and best remembered 0:00:30.400 --> 0:00:32.760 during the R E M stage of sleep. It's also 0:00:32.760 --> 0:00:36.280 pretty commonly accepted among the scientific community that we all dream, 0:00:36.400 --> 0:00:38.879 though the frequency in which dreams are remembered varies from 0:00:38.920 --> 0:00:42.239 person to person. The question of weather dreams actually have 0:00:42.400 --> 0:00:46.839 a physiological, biological, or psychological function has yet to be answered, 0:00:47.080 --> 0:00:50.440 but that hasn't stopped scientists from researching and speculating. There 0:00:50.440 --> 0:00:53.600 are several theories as to why we dream. One is 0:00:53.640 --> 0:00:56.240 that dreams work hand in hand with sleep to help 0:00:56.280 --> 0:00:59.320 the brain sort through everything it collects. During the waking hours. 0:00:59.720 --> 0:01:02.400 Your brain is met with hundreds of thousands, if not millions, 0:01:02.400 --> 0:01:05.560 of inputs every day. Some are minor sensory details like 0:01:05.600 --> 0:01:07.959 the color of a passing car, while others are far 0:01:08.040 --> 0:01:10.600 more complex, like the big presentation you're putting together for 0:01:10.640 --> 0:01:13.560 your job or class. During sleep, the brain works to 0:01:13.600 --> 0:01:15.959 plow through all of this information to decide what to 0:01:15.959 --> 0:01:18.920 hang onto and what to forget. Some researchers think that 0:01:19.000 --> 0:01:21.760 dreams play a role in this process. It's not just 0:01:21.800 --> 0:01:24.000 a stab in the dark, though. There is some research 0:01:24.040 --> 0:01:26.319 to back up the ideas that dreams are tied to 0:01:26.400 --> 0:01:29.800 how we form memories. Studies indicate that as we're learning 0:01:29.840 --> 0:01:32.640 new things in our waking hours, our dreams increase while 0:01:32.640 --> 0:01:35.440 we sleep. Participants in a dream study who are taking 0:01:35.480 --> 0:01:38.119 a language course showed more dream activity than those who 0:01:38.160 --> 0:01:40.880 were not. In light of such studies, the idea that 0:01:40.920 --> 0:01:43.240 we use our dreams to sort through and convert short 0:01:43.360 --> 0:01:46.320 term memories into long term memories has gained some momentum 0:01:46.319 --> 0:01:50.560 in recent years. Another theory is that dreams typically reflect 0:01:50.560 --> 0:01:53.520 our emotions during the day, our brains are working hard 0:01:53.600 --> 0:01:56.800 to make connections to achieve certain functions. When posed with 0:01:56.840 --> 0:02:00.120 a tough math problem, your brain is incredibly focused on 0:02:00.120 --> 0:02:03.240 one thing, and the brain doesn't only serve mental functions. 0:02:03.640 --> 0:02:05.640 If you're building a bench, your brain is focused on 0:02:05.720 --> 0:02:08.399 making the right connections to allow your hands to work 0:02:08.400 --> 0:02:10.640 in concert with the saw in the wood to make 0:02:10.680 --> 0:02:13.600 an exact cut. The same goes for simple tasks like 0:02:13.680 --> 0:02:16.160 hitting a nail with a hammer. Have you ever lost 0:02:16.200 --> 0:02:18.600 focus and smashed your finger because your mind was elsewhere. 0:02:19.320 --> 0:02:23.080 Some researchers have proposed that while sleeping, everything slows down. 0:02:23.520 --> 0:02:26.320 We aren't required to focus on anything during sleep, so 0:02:26.360 --> 0:02:29.679 our brains make very loose connections. It's during sleep that 0:02:29.720 --> 0:02:31.480 the emotions of the day battle it out in our 0:02:31.520 --> 0:02:34.120 dream cycle. If something is weighing heavily on your mind 0:02:34.200 --> 0:02:36.320 during the day, chances are you might dream about it, 0:02:36.320 --> 0:02:39.840 either specifically or through some kind of imagery. For instance, 0:02:39.840 --> 0:02:42.600 if you're worried about losing your job due to company downsizing, 0:02:42.919 --> 0:02:44.919 you may dream that you're a shrunken person living in 0:02:44.960 --> 0:02:47.639 a world of giants, or that you're wandering aimlessly through 0:02:47.639 --> 0:02:51.720 a great desert abyss. There's also a theory, definitely the 0:02:51.800 --> 0:02:54.480 least intriguing of the bunch, that dreams don't really serve 0:02:54.520 --> 0:02:57.000 any function at all, that they're just a pointless byproduct 0:02:57.040 --> 0:03:00.040 of the brain firing wallaby slumber. We know that a 0:03:00.120 --> 0:03:02.440 rear portion of our brain gets pretty active during r 0:03:02.639 --> 0:03:05.480 M sleep, when most dreaming occurs. Some think that it's 0:03:05.520 --> 0:03:07.600 just the brain winding down for the night, and that 0:03:07.760 --> 0:03:11.040 dreams are random and meaningless firings that we don't have 0:03:11.120 --> 0:03:14.079 when we're awake at the end of the day. As 0:03:14.120 --> 0:03:16.280 long as the brain remains such a mystery, we probably 0:03:16.320 --> 0:03:19.399 won't be able to pinpoint with absolute certainty exactly why 0:03:19.440 --> 0:03:27.560 we dream. Today's episode was written by Charles W. Bryant 0:03:27.600 --> 0:03:30.000 and produced by Tristan McNeil. For more on this and 0:03:30.160 --> 0:03:32.800 lots of other dreamy topics, visit our home planet, how 0:03:32.840 --> 0:03:45.320 Stuff Works dot com.