Multitasking is actually not possible for humans; what we think of as multitasking is really just switching our attention between tasks
Remove distractions before you study as distractions result in decreased learning
You just finished dinner and you finally sit down with your digital textbook to study when you get a text from a friend. You check your phone and it turns out you actually have 3 unread texts! After answering the first friend, you go back and read your other messages, replying as you come to them. You and your friends send a few texts back and forth, and one sends a hilarious gif. You laugh out loud and have to share it with another friend, so you open up your social media to share it.
When you open your social media you see a few unread notifications so you check out your notifications and then scroll your feed for a little bit to see if there is anything new going on. You suddenly realize you forgot to share the gif, so you find your friend and send them the gif. You look up from your phone for a second and you see your digital textbook, still waiting for you to study, and you realize you spent the last 20 minutes distracted from studying. You put your phone away and decide to start studying.
Multitasking is frequently defined as doing two things at the same time, but it is actually impossible for your brain to focus on two things at the same time. If you think you are a really good multitasker, you might be a great task switcher, but you cannot attend to two different stimuli at the same time. Task switching is simply repeatedly switching what you pay attention to (like two different tasks), but you are only paying attention to one thing at a time.
For example, I can talk on the phone while I drive, but this isn’t multitasking because I can only focus on either driving or talking, not both at the same time. This is actually kind of dangerous because task switching impedes task performance. This means I am slightly worse at talking on the phone and slightly worse at driving while I am task switching between the two. In this case, task switching could affect my driving which could have deadly consequences.
Kaitlyn May and Anastasia Elder conducted a literature review study in 2018 that examined 38 articles from 2003 to 2017 that researched the effect of task switching on learning. They found that trying to do too many things at the same time resulted in less effective learning, lower exam scores, and decreased study efficiency.
May, K. E., & Elder, A. D. (2018). Efficient, helpful, or distracting? A literature review of media multitasking in relation to academic performance. International Journal of Educational Technology in Higher Education, 15(1), 13.