TikTok's personalized algorithm activates the brain's reward system

Why TikTok's algorithm is likely driven by what you linger on

While the inner workings of the engine driving the vast majority of the app's engagement remain a secret, it is understood to rely heavily on what content users spend the most time watching rather than swipe past. Experts believe the app can develop user profiles robust enough for its algorithm to consistently match engaging content to in as little as two hours.

How TikTok ate the internet

TikTok is now deeply integrated into American culture, thanks to the app’s powerful algorithm and focus on entertainment which have influenced popular trends and social media content consumption in the US. This immersive piece highlights TikTok’s role in helping shape everything from music to fashion and even politics in the US—while its connection to China has also drawn scrutiny and raised national security concerns.

TikTok boasts nearly 1.8B monthly users

The app has surged in popularity recently, with usage surging during the COVID-19 pandemic. Those users have generated high revenues, too, with over $23B in 2024.

TikTok's algorithm has changed the way hits are made

Songs aimed at TikTok's algorithm—designed for viral dances or soundtracking common experiences—often find success on the Billboard charts. An early example was Lil Nas X's "Old Town Road," which used his memes and a country-trap beat from the Netherlands to rise to the top of the Billboard charts.

Less than half of TikTok's US users have posted a video

Like most platforms, content is driven by a small number of active users—in TikTok's case, 25% of accounts are responsible for an estimated 98% of content posted.

How to read the news on TikTok

There's plenty of news on TikTok, but that doesn't mean it's all reliable. This guide, written by a communication technology professor, breaks down the ways the app's algorithm delivers news. It also covers how users can determine whether or not a story is factual or misleading. Most strikingly, the professor warns readers that if they didn't search for a TikTok video, then "it probably found you."

TikTok's 'sonic logo' imprints the app's identity across platforms

As the app's popular videos spread to other platforms like Instagram and Reddit, the company sought a way to alert viewers that the content originated on TikTok. They decided on the sonic logo that now acts as a bumper on all of its shared videos, to attract users.

Understanding TikTok-owner ByteDance's business model

ByteDance has ridden TikTok's major success to become the world's most valuable startup. This deep dive showcases some of the company's smartest moves and tactics, and where it's headed next.

Facebook's algorithm chooses content to display on the News Feed based on user data

It employs machine learning to prioritize posts and ads based on user interactions, content type, and post timeliness, creating a personalized, engaging experience for each user.

The reason some people love exercise may be because of their microbiome

Certain gut microbes in mice trigger dopamine release and drive motivation to exercise more. Scientists are investigating whether humans carry similar microbial patterns that influence our natural inclination towards movement, exploring how unseen microbial ecosystems may shape mammalian fitness behavior and reinforce innate reward pathways. (Some users may experience a paywall.)

Meta has added video features to attract more young users to Facebook

Amid an aging userbase and competition from newer social networks like TikTok, Facebook has seen its perceived relevance and cool factor progressively decrease. The Local tab and dating features are among several efforts to counter this perception.

What’s with the teen brain, anyway

In this video NIDA explores the intriguing similarities between the processes of brain development and computer programming. This analogy helps us understand why toxic environmental factors like drugs, bullying, or lack of sleep strongly affect a teenager’s life The information provided by this video can empower your children or students with information they need make better decisions.

In 2019, videos on TikTok convinced children they had Tourette syndrome

Right before the COVID-19 pandemic, an "outbreak" of Tourette syndrome was attributed to videos from a German TikToker who documented his life with the condition. The children experiencing the symptoms all had the same tics, which experts say was a case of mass sociogenic illness, also referred to as mass hysteria.

Why TikTok loves Rainer Maria Rilke

It seems like an odd fit: A social media app known for bite-sized videos and a long-dead Austrian poet. Despite the odds, Rilke, especially his famous "Letters to a Young Poet," has become an unexpected trend on TikTok, where influencers share his wisdom on creativity and self-discovery.

Addictive drugs can cause dopamine levels to become ten times higher than normal

Now recognized as a physiological brain disease, addiction rewires the brain's reward system to make drugs feel necessary and weaken self-control by dulling the relative effects of natural rewards like food and social connection.

Deepfake videos impersonating real doctors are spreading false medical advice

More than 100 videos, found primarily on Instagram and TikTok in August 2025, promoted products related to beauty, wellness and weight loss. While TikTok removed 94% of content violating its policies on AI-generated content, these deepfakes were watched and shared before removal, undermining public trust in medicine.

How to help teens balance social media use and mental healthcare

While initially alluring, excessive social media use is proven to lead to increased feelings of isolation, mental health declines, increased stress, and general dissatisfaction among teens. Conducting digital audits to track screen time, adding friction (or obstacles) to app usage to reduce mindless scrolling, and investing time in offline activities and hobbies may help.

Some experts equate prediction markets to the new crack cocaine of gambling addiction

An addiction psychiatrist at UCLA says betting apps are far more potent than traditional gambling, citing a 19-year-old patient who lost $180,000 and hadn't left campus in a year, cycling through sports bets, crypto, meme stocks, and prediction markets on his phone. This interview explores the extreme edge of the nascent industry.

Gen Z's love for perfume is boosting sales

Teen boys are the biggest driver in perfume sales as of the summer of 2025. They have increased their spending on fragrances 26% year-over-year as the trend blossoms on TikTok via #PerfumeTok. Additionally, users of weight loss drugs GLP-1 agonists are adding to sales, as they seek olfactory over culinary sensations.

Temu uses gamification techniques to encourage customers to shop on its app

Games include a spinning roulette wheel that offers coupon rewards, promises free delivery, and more. Some have said it’s tough to pull themselves out of the Temu ecosystem once they’re in it.

Why we pay to be scared

Why do we love roller coasters? It’s not just the speed or height, it’s controlled fear. Your brain thinks you’re in danger, then rewards you with dopamine.

Scientists are learning to guide your dreams using sound and touch

Researchers are using a technique called "targeted dream incubation"—where stimuli like sounds or vibrations are introduced as you drift off—to influence dream content and potentially improve creativity, memory consolidation, and PTSD treatment. With the same mechanism, companies could theoretically target sleeping consumers with brand suggestions while they're unaware and neurologically susceptible, or assist in reducing nightmares.

Peloton's success is partly due to users' relationships with instructors

Despite Peloton's online model, most users feel a deep connection with the instructors and have created community groups around their shared identities (like being a mom or a lawyer). The relationship users have with their instructors has fueled consistent engagement and paved the way for instructors to take on personal brand deals. (Some users may experience a paywall.)

Fast-casual restaurant Chili's is experiencing a resurgence, with its parent company recently reporting a nearly 32% increase in sales, thanks to passionate Gen Z fans on TikTok.

Watch how algorithms can be designed to train themselves and self-improve without human input, to the point where the optimized code is too complex for programmers to understand.

Pay transparency 101

The star of this Harvard Business Review video interviews experts—from an organizational psychologist and business professor to a TikToker who asks people how much money they make—to get to the bottom of core issues about pay transparency. Why is talking about money becoming less taboo? How do pay transparency laws impact workers, employers, and office culture? Watch this video to find out.

Button boards may be the next step in human-canine communication

In a viral trend, dogs have been recorded using button boards to seemingly "talk" with humans. Researchers are divided on whether this means dogs have learned language or are engaging in sophisticated behavioral conditioning.

This site reaches millions of visitors who are tired of AI chatbots and seeking human connection. Pretend to be an AI chatbot and ask questions, provide answers, and draw for people in real time.

Children are now three times more likely to say they want to be a YouTuber when they grow up than an astronaut, with some even attending 'YouTube camps' that teach kids how to create content for the platform.

Explore an interactive map built from more than 100,000 survey responses on where people find joy in their lives

After 25 people used virtual reality headsets to practice flying with virtual wings—flapping their arms—their visual cortex responded to the wings almost as if they were real arms, treating them as body parts.

Netflix profits when you're not watching, and its movies are designed that way—read a detail-rich critical essay exposing lesser-known Netflix takes

Studies suggest when you sleep is as important as how much you get, and syncing with your circadian rhythms may lead to less fatigue and improved long-term health outcomes

In 2025, four executives from large tech companies were given positions in the US Army Reserves—including Palantir Chief Technology Officer Shyam Sankar, which reinforced Palantir's ties with the US military and its role as a leading defense partner.

Telehealth demand for GLP-1s for weight loss is booming as consumers seek easier access.

Alzheimer's can lead to brain shrinkage, with an average of around 2% of volume reduction per year

Memecoins are a type of cryptocurrency—a form of digital currency with a wide variety of uses—created around popular 'memes,' or viral internet jokes.

US consumers collectively owe more than $1T to credit card companies—almost as much as they owe in auto loans.

Fireworks-related ER visits are on the rise—in 2024, they increased by 52% as compared to the prior year.

The hormonal disorder PCOS was renamed PMOS in 2026, a move designed to improve care and research by shifting the focus to the hormonal causes of this condition that affects 1 in 8 women.

Up to a million Girl Scouts sell about 200 million cookie boxes every spring, generating $800 million, largely because refusing a child is frowned upon

The Nasdaq's 'Magnificent 7' companies are responsible for roughly 40% of the Nasdaq 100 index's gains, while the remaining 93 companies account for the other 60%.

Fear or disgust related to clusters of holes and cracks, called trypophobia, may stem from evolutionary processes to help us avoid pathogens.

Clever Hans was a 1900s horse that was believed to be able to solve math equations, tell time, and read and comprehend German, until a psychology student discovered how he got his answers.

Hear 50 years of iconic hip-hop samples, the genre's foundational looped tracks

Massive blooms of microscopic plankton called dinoflagellates produce the neon blue light seen in glowing tides.

Chaos theory—informally known as the butterfly effect—is the reason why weather forecasts are presented with probabilities rather than certainties.

Dorothy's famous entrance into Oz in 'The Wizard of Oz' relied on analog tricks, including a body double and sepia-toned paint, as much as it did on technology

Art theft is the third-largest source of criminal revenues worldwide, thanks in part to the subjective nature of valuing a work of art.

Prince's sexually explicit 1984 track 'Darling Nikki' attracted the ire of the Parents Music Resource Center, an advocacy group that inspired the Parental Advisory sticker, even though the song ends with a Christian message.