Knowing Neurons
Science PolicyBrain DevelopmentCognitionSleep

How TikTok Hijacks Your Brain

By Caitlin Goodpaster

TikTok, a video-sharing app that has taken the world by storm, was first introduced as Douyin in 2016 in China, where it gained 100 million users in just one year (“TikTok”, 2023). With increasing momentum, this mobile platform, which allows users to create and share short-form videos, expanded outside mainland China with an international rebrand as “TikTok” in 2018. Today, TikTok boasts 1.58 billion users with active users spending 2700 minutes on the app each month (Ruby, 2023). This rise to fame has largely been credited to TikTok’s proprietary algorithm that curates a stream of videos that uniquely match your interests. While this concept is not new—many social media platforms, including Instagram and YouTube, operate similarly—TikTok seems to have hacked our brains better than most.

In 2021, an internal document “TikTok Algo 101” was leaked to the New York Times. It outlines the basic inner workings of TikTok’s algorithm, which is aimed at accomplishing two goals: increasing daily users and making content creation increasingly lucrative. To accomplish this, their system tracks every movement you make on the app, and even off the app (TikTok Privacy Policy, 2023). This includes how much time you spend watching a video, the number of times you watch it, and video interactions, such as likes and comments (Smith, 2021). Researchers in China have found that TikTok’s personalized video streams preferentially activate parts of your brain’s reward system, including the ventral tegmental area (VTA; Su et al., 2021), likely because they tap into your specific interests.

Researchers in China have found that TikTok’s personalized video streams preferentially activate parts of your brain’s reward system

The VTA, along with the nucleus accumbens and medial prefrontal cortex (mPFC), comprise the mesocorticolimbic system which is highly implicated in motivated behavior, reward responses as well as learning and memory (Reynolds & Flores, 2021; Cai and Tong, 2022). Additionally, neurons originating in the VTA release dopamine, a neurotransmitter linked to motivated behavior (Morales and Margolis, 2017). Su et al. (2021) found that the VTA is activated when watching TikTok’s curated content, however, the researchers did not see increased activation in the VTA when you watch un-curated content. Another study in the US utilizing animal and human models found a novel pathway between mPFC and anteromedial thalamic nucleus to be highly involved in motivated behavior and dopamine in mice. These regions were then shown to be more active in humans when viewing TikTok-suggested videos (Yang et al 2022). Hijacking your brain’s reward system increases craving for more screen time, a phenomenon that is akin to addiction. And the more you watch, like, and share their videos, the more money you generate for content creators, advertisers, and the company itself.

Hijacking your brain’s reward system increases craving for more screen time, a phenomenon that is akin to addiction. And the more you watch, like, and share their videos, the more money you generate for content creators, advertisers, and the company itself.

A large amount of screen time for children has also been linked to shorter attention spans and stronger desire for instant gratification in younger generations. While not solely responsible, TikTok’s popularity and introduction of its signature short-form videos have taken heavy blame in recent years (Koetsiet, 2020). Unlike its predecessors, TikTok doesn’t require users to choose which videos to view. Instead, they create a continuous stream of content that’s immediately available upon opening the app. Reducing the amount of time between grabbing your phone and watching that first video leads to increasing instances of faster gratification. In other words, users can satisfy their urge to scroll—and trigger their brain’s reward system—much more quickly. Additionally, videos are only 15-60 seconds long on average, and TikTok’s algorithm aims to queue up a variety of topics to stave off boredom (“TikTok”, 2023). With each passing video, our brains receive a hit of dopamine. Over time, our brain’s reward system habituates—or gets used to—this high level of dopamine, requiring more and more of it reach the same level of satisfaction. This will make it harder for other experiences, like ones in the real world, to elicit the typical reward response. This is especially impactful for children whose brains are not yet developed.

There is some evidence that TikTok’s parent company in China, ByteDance, is aware of the effects they are having on young children. Unlike TikTok, China’s Douyin app has stiff restrictions for those under the age of 14. Children younger than this cannot spend more than 40 minutes on the app per day and can’t access it between 10pm and 6am (BBC, 2021; Yeung & Wang, 2023). These restrictions are part of China’s larger crusade to reduce recreational screen time for kids. For example, minors in China also cannot play online video games during the week and are even limited to just 3 hours on weekends (CNN, 2021). These stark differences in how ByteDance runs its TikTok branch versus Douyin highlights their awareness of the negative impact that unhealthy online habits can have on early development.

… users can satisfy their urge to scroll—and trigger their brain’s reward system—much more quickly

Beyond the threat that TikTok poses to the developing brains of the world, privacy concerns are currently making headlines. Given that the app’s algorithm is kept under wraps from the general public, there are concerns that ByteDance is not adequately protecting users’ private information (Perrigo, 2023). Since ByteDance is located in China, and companies within China are beholden to the communist state, there are concerns in the US, EU, and other nations that their citizens’ information is being could be collected and utilized by the Chinese Communist Party (Zahn, 2023). TikTok has already been banned in nations that are antagonistic towards China, including India and Bangladesh (D’Souza, 2023). Currently, similar proposals are being made in the US and Europe to follow in their footsteps if the company does not adequately address privacy concerns (D’Souza, 2023).

While the government may be more concerned with the security of your private data than with the development of our children, there’s evidence that a ban might not be so bad after all. Although, even with a TikTok ban, with platforms like YouTube Reels and YouTube Shorts there would still be plenty of places to get your TikTok fix. However, perhaps reducing this form of entertainment overall would leave more room for experiences and people in real life to be responsible for activating your brain’s reward system.

~~~

Written by Caitlin Goodpaster
Illustrated by Sumana Shrestha
Edited by Zoe Dobler, Daniel Janko, and John Zhou

~~~

Become a Patron!

image of a person standing by a circle that is circling an image of the brain and a phone with a tiktok logo
References

Cai J, Tong Q. Anatomy and Function of Ventral Tegmental Area Glutamate Neurons. Front Neural Circuits. 2022 May 20;16:867053. doi: 10.3389/fncir.2022.867053.

Koetsier, J. (2020, January 18). Digital Crack Cocaine: The Science Behind TikTok’s Success. Forbes. https://www.forbes.com/sites/johnkoetsier/2020/01/18/digital-crack-cocaine-the-science-behind-tiktoks-success/?sh=6a009ac378be

Morales, M., Margolis, E. Ventral tegmental area: cellular heterogeneity, connectivity and behaviour. Nat Rev Neurosci 18, 73–85 (2017). https://doi.org/10.1038/nrn.2016.165

Perrigo, B. (2023, March 23). What to Know About the TikTok Privacy Concerns. Time Magazine. https://time.com/6265651/tiktok-security-us/

Reynolds LM, Flores C. Mesocorticolimbic Dopamine Pathways Across Adolescence: Diversity in Development. Front Neural Circuits. 2021 Sep 8;15:735625. doi: 10.3389/fncir.2021.735625.

Ruby, D. (2023, January 20). 36 TikTok Statistics 2023: How Many Users Are There! DemandSage. https://www.demandsage.com/tiktok-user-statistics/

Smith, B. (2021, December 5). How TikTok Reads Your Mind. The New York Times. https://www.nytimes.com/2021/12/05/business/media/tiktok-algorithm.html

Souza, D. (2023, February 23). TikTok: What It is, How It Works, and Why It’s Popular. Investopedia. https://www.investopedia.com/what-is-tiktok-4588933

Su, C., Zhou H., Gong L., Teng B., Geng F., Hu Y. Viewing personalized video clips recommended by TikTok activates default mode network and ventral tegmental area. NeuroImage 237, 118136 (2021). https://doi.org/10.1016/j.neuroimage.2021.118136.

Yang, C., Hu, Y., Talishinsky, A.D. et al. Medial prefrontal cortex and anteromedial thalamus interaction regulates goal-directed behavior and dopaminergic neuron activity. Nat Commun 13, 1386 (2022). https://doi.org/10.1038/s41467-022-28892-7

Yeung J., Wang, S. (2023, March 24). TikTok is owned by a chinese company, So why doesn’t it exist there? CNN. https://www.wvtm13.com/article/tiktok-chinese-company-why-doesnt-it-exist-in-china/43408158#

Zahn, M. (2023, March 28). No evidence of TikTok national security threat but reason for concern, experts say. ABC News. https://abcnews.go.com/Technology/evidence-tiktok-national-security-threat-reason-concern-experts/story?id=98149650

(2021, August 30). China Cuts children’s online gaming to one hour. BBC. https://www.bbc.com/news/technology-58384457

(2021, August 31). China bans kids from playing online video games during the week. CNN.
https://www.cnn.com/2021/08/31/tech/china-ban-video-games-minor-intl-hnk/index.html

TikTok (2023, March 28). In Wikipedia. https://en.wikipedia.org/wiki/TikTok

(2023, March 21). TikTok Privacy Policy. https://www.tiktok.com/legal/page/us/privacy-policy/en

Author

  • Caitlin Goodpaster

    Caitlin earned her Bachelor’s degree at The Ohio State University before joining the Neuroscience Interdepartmental PhD Program at the University of California, Los Angeles. In the lab of Dr. Laura DeNardo, she studies how early life stress impacts prefrontal circuitry throughout development and contributes to alternations in avoidance behaviors. She is passionate about understanding how early experiences can lead to the development of atypical behaviors and is motivated to eliminate to stigma surrounding mental illness.

Caitlin Goodpaster

Caitlin earned her Bachelor’s degree at The Ohio State University before joining the Neuroscience Interdepartmental PhD Program at the University of California, Los Angeles. In the lab of Dr. Laura DeNardo, she studies how early life stress impacts prefrontal circuitry throughout development and contributes to alternations in avoidance behaviors. She is passionate about understanding how early experiences can lead to the development of atypical behaviors and is motivated to eliminate to stigma surrounding mental illness.