2023-07-18 by Shakunthala Natarajan

Why Do We Dream? Science Blog

Listen to the full episode, here.

The large hall is fully packed and well-lit! You find yourself on the centre stage, receiving the citation and medal for the coveted Nobel prize in your domain :) The crowd cheers, camera lights flash in succession, and you are on cloud nine! But suddenly, you are cut short by a familiar voice… It’s your mother waking you up for the day. And you realize that you were dreaming of being a Nobel laureate! But now you start wondering why we dream at all. You will get your answer in this podcast of IndiaAsksWhy where three of our curious listeners - Navika, Fareeha, and Satakshi embark on this journey to learn about dreams with Utsuka and Jigyasa.

Before we look at the reasons behind dreaming, you must be wondering what are dreams in the first place. A dream can be thought of as a chain of thoughts, or visualizations that occur during a particular stage of our sleep. Sleep and dreams have been researched for a long time. But one puzzling question in the field is, ‘What is the purpose of dreams?’. Well, there are many theories put forth by scientists. One idea tells us that we dream all the time. But it is only during sleep that other senses active during the day stay silent, for us to perceive the dream state. But another hypothesis put forth by scientists suggests that dreaming could be an outcome of the data-sorting mechanism for the brain. Throughout the day we collect numerous details, of which some could be important, while others could be irrelevant. Hence, dreams are outcomes of the data sorting process in the brain, where important information is stored in long-term shelves while unnecessary information gets removed. While organizing information in specific compartments, the brain replays the details, which causes some data leaks that transform into dreams. It’s like the ‘ store the best, and trash the rest’ policy! But you must be curious to know the storage space in the brain that is responsible for long-term memory. In mammals, a tiny part of the brain called the hippocampus acts as the long-term memory store-keeper! Hippocampus - a tiny space for humongous data storage indeed resembles a biological chip :)

Having looked at the purpose of dreams, our three new friends, Navika, Fareeha, and Satakshi are excited to know the reason behind the bizarre dreams that we have. Can you recall some of your dreams? Some might have had incoherent events while others would have unrelated components that are really strange. For example, you might have imagined yourself seated in a flying car that is about to land on the ocean 😅 How does the brain make such weird connections? This leads us to information segregation in the brain again. Let’s look at this more closely. The rapid eye movement (REM) stage of sleep is one of the different stages of sleep. During this stage, the entire body except for the eyes and the diaphragm is in a paralysis-like state and this sleep is called ‘light sleep’. This REM sleep occurs quite a number of times during our sleep cycle and lasts for around 90 minutes. Coming back to strange dreams, our brain tries to process multiple sets of information at a time and this multitasking leads to unrelated data being connected over and spilled into the dream realm! This mostly occurs during the REM sleep close to our waking hours. Wait. Do you think that you can recall such strange dreams more than normal dreams? That’s true! In our daily lives, we tend to remember more emotional events. The Hypothalamus, the part of the brain associated with emotions is still active during sleep. It helps us recall strange dreams that heighten our emotional responses.

Our enthusiastic exploration team is amazed by dreams, just like you! They further wonder, if sleep is common to all organisms like cats, and cows, then do animals dream as well. Let us join them as they talk with Dr Nitin Singh Chauhan, a sleep scientist from the Tata Institute of Fundamental Research (TIFR), Mumbai, to learn more about sleep and dreams. From the conversations, we find that indeed all animals dream! Maybe learning more about sleep in animals will help us look at their dreams in a better way. Let’s move on. It is very interesting to hear from Dr Chauhan who says that, like dreams, even the idea behind sleep has not been uncovered fully. If we look at it from a threat perspective, when we sleep, we are more vulnerable to external threats. We are not really sure as to why we sleep for such a long time, exposing ourselves to vulnerabilities. Why can’t we just lie down and rest without sleeping? Maybe, the budding scientist in you will help us understand sleep further in the near future?! However, we do understand what will happen when we do not sleep. Studies show that lack of sleep leads to defective physiological and cognitive functions, and these in turn impact our daily lives. So essentially, a sound sleep leads to a healthy body and active mind.

We have now come to the end of our journey into the world of dreams. I bet that you must be more curious to experience the dream land with our enthusiastic explorers team headed by Utsuka and Jigyasa. It is time to gear up your headphones and tune in to the podcast. Happy learning! And don’t forget to catch a good night’s sleep to process all the important details you have gathered from your curiosity journey with us!

Listen to the full episode, here.

References

Dreams: Why we dream & how they affect sleep (2023) Sleep Foundation. Available at: [https://www.sleepfoundation.org/dreams]https://www.sleepfoundation.org/dreams() (Accessed: 10 September 2023). Eagleman, D., Vaughn, D. and Livewired: The Inside Story of the Ever-Changing Brain (2020) Why do we dream? A new theory on how it protects our brains, Time. Available at: https://time.com/5925206/why-do-we-dream/ (Accessed: 10 September 2023). professional, C.C. medical (no date) The amygdala: A small part of your Brain’s biggest abilities, Cleveland Clinic. Available at: https://my.clevelandclinic.org/health/body/24894-amygdala (Accessed: 10 September 2023). Roland, J. (2023) Why do we dream? the role of dreams and nightmares, Healthline. Available at: https://www.healthline.com/health/why-do-we-dream#why-do-we-have-nightmares (Accessed: 10 September 2023). Strogatz, S. and Quanta Magazine moderates comments to facilitate an informed, substantive (2022) Why and how do we dream?, Quanta Magazine. Available at: https://www.quantamagazine.org/why-and-how-do-we-dream-20220824/ (Accessed: 10 September 2023). Team, B. and S. (2022) Why do we dream?, Cleveland Clinic. Available at: https://health.clevelandclinic.org/why-do-we-dream/ (Accessed: 10 September 2023). TOI Education / May 4, 2023 (no date) Why do we dream while sleeping? - times of India, The Times of India. Available at: https://timesofindia.indiatimes.com/education/learning-with-toi/why-do-we-dream-while-sleeping/articleshow/99951016.cms (Accessed: 10 September 2023).