The Psychology Behind TikTok's Addictive Feed

Use your keyboard arrows
to view the story!

Growth.Design Case Study #023
Story Duration: 4 min

Pro tip: Use landscape mode!

Avatar displaying current emotion

The other night I was in my couch watching Netflix's troubling docu-drama "Social Dilemma".

It mentioned TikTok.

Which made me realize that…

Avatar displaying current emotion


…I've never tried TikTok before.

I just heard that its feed was fun and addictive.

But I thought that a good laugh in these stressful times couldn't hurt so…

I downloaded TikTok.


Avatar displaying current emotion

Hm, I was expecting TikTok's video feed right from the start… not a wall of buttons.

At least they allow me to "Skip"!

Let's do this… {TAP}

Avatar displaying current emotion

Hmm… 20 options?
That's a lot!

Especially since—

—TikTok's feed algorithm relies on your behavior way more than these manual options.

(…you'll see in a minute)

Avatar displaying current emotion

These 6 categories 
could've covered the most common cases*.

*Based on the data of TikTok's and 5by's most popular videos and reasons why people used their app.

Avatar displaying current emotion

But for now let's go with a sure bet:

Comedy and Animals!


Avatar displaying current emotion

Seems simple enough!


Avatar displaying current emotion

The first video instantly got my attention…

Nice! Considering that I chose
"Comedy" and "Animals"…

…this skateboarding bird (with 3.4M likes!) seems like a great choice by the algorithm.

Avatar displaying current emotion

Also, unless you manually pause the default video loop, it keeps you engaged and eliminates any downtime.

Notice how immersive this full-screen interface is.

Now… what should I do next to—

Immersive Experiences

Distraction-free interfaces can greatly increase your user engagement.

Whether that's for surveys (Typeform), productivity apps (Notion), and even content (this case study immersed you enough to read until here 😉).

For example, we saw a 280% increase in user engagement for our case studies when we defaulted them to fullscreen.1

1Growth.Design, Private experiment (2020)
Avatar displaying current emotion


TikTok's automatic reminder was perfectly timed.

Habits = Dominos

This nudge might seem trivial.

It's not.

It's THE MOST important action of TikTok's onboarding. You see, habit-forming products behave like dominos:


The more you swipe, the more likely you are to keep swiping.1

But TikTok needs you to swipe juuuuust once to start the chain reaction.

Their end-goal is to get you to swipe without even thinking about it (habit).

1BJ Fogg, TEDx talk on Habits (2016)

So I swiped… and what I saw next surprised me even more…

Avatar displaying current emotion

Woah! Impressive content personalization

I'm indeed in Montreal
(🇨🇦 Canada) right now, but—

Avatar displaying current emotion

—I did not share my location explicitly yet.

There's only one way to explain this…

IP Sniffing for Personalization

TikTok detects and uses your IP address to personalize your content based on what people around you enjoy.

But even if this eliminates the need for an extra iOS "Location Services" permission request, it could feel intrusive.

Especially in the context of TikTok's poor reputation when it comes to privacy and handling user data.1

1Washington Post, Is it time to delete TikTok? (2020)

Anyways, let's keep moving…


Avatar displaying current emotion

Avatar displaying current emotion


I didn't see that one coming—well done!

Sticky Content

Popular videos on TikTok (like this one) all have the same things in common:

1. Simple (very short and basic)
2. Unexpected (curiosity gap)
3. Concrete (e.g. relevant to COVID19)
4. Emotional (fun/fear, music-driven)
5. Story (e.g. woman looking for a mask)

Science shows that those are 5 of the key elements to make an idea stick.1

1Made To Stick, Chip Heath and Dan Heath (2007)

This funny video looped many times while I showed it to someone next to me…

…and TikTok's feed adapted accordingly…

Avatar displaying current emotion

Oh… is TikTok now testing my reaction to funny videos instead of animals?…


The next few swipes brought me more funny (but weird) videos, until—

Avatar displaying current emotion

Now, this video looks cool, but if I watch it too much…

…will my feed be filled with rollercoasters?

Observer-Expectancy Effect

You behave differently when you know you're being observed.1

For apps that rely on behavior-based personalization (like TikTok), that's a problem since people will eventually hesitate to explore—or worst—get stuck in a content rabbit hole.2

A simple solution might be an "Incognito Mode" (like in Youtube).

1Growth.Design, 101 Cognitive Biases (2020)

I'm almost afraid to explore content that deviates too much from what I usually watch.


Avatar displaying current emotion

I swiped again, and once more—

Hmm… why am I seeing a video with so few likes and comments now?

—oh… I didn't realize this was a "promoted" advertisement.

Seems like TikTok waited for me to be engaged before they sneaked in some ads… clever.

Still, this reminds me of the
"Evil Revenue Algorithm" from the documentary "Social Dilemma":

Avatar displaying current emotion

—TikTok pulled me back into a rabbit hole of engaging videos.

But each "swipe up" felt more and more like I was pulling down the handle of a slot machine

…which made me realize the
#1 psychological effect that makes TikTok's feed so addictive…

Variable Rewards & Habits

TikTok videos are more addictive than other social platforms for three reasons1:

  1. ⏳ Short: 16 seconds in average (9x shorter than Facebook's average). The feed hence adapts faster.
  2. 👉 Snapped: There's no "aim" needed, just flick your finger and the video will be immersive every time.
  3. 💥 Surprising: You either learn, laugh or be weirded out, but you always get something personalized.

This mix of very low cognitive task and high variability makes TikTok a textbook example of "addiction-forming design".

1Vox, TikTok behind the scenes (2020)

I swiped through 183 more videos.

It was like eating dessert non-stop… while being already full. And then…

…I saw something I didn't expect—

Avatar displaying current emotion

I understand it's easy to keep watching videos [...]

But those videos will still be there tomorrow so go get some sleep!

—a "Digital Wellbeing" video…
…made and promoted by TikTok.

Avatar displaying current emotion

Hmm, feels like false empathy.

Three key elements are missing to make this nudge work…

Providing Exit Points

Allow users to disengage from your product with a sense of completion.1

If not, people will associate your product to a never-ending list of tasks (or an addictive slot machine in this case).

Not only it might help your long-term user retention, but most importantly…

…it's the Humane thing to do.

1Growth.Design, 101 Cognitive Biases (2020)

If TikTok's really cared about my wellbeing…

…they would have stopped me earlier with something like this

1) 🚧 Pattern Break: The familiar video format doesn't stop me in my tracks.

2) 💉 Friction: I'm still just ONE addictive swipe away from the next video.

3) ⏳ Loss: I've wasted a LOT of time by now. Highlighting that duration would make this more tangible.

Oh, and one last thing for you 

Psych Level

🧠 User Psychology Cheatsheet

Get the 101 psychological principles that affect your UX. Wrapped in a nice 2-pager.

Yes, I Want My Cheatsheet!



Customer Journey

So far, here are the key moments in this TikTok experience...

—allow the feed to adapt to my watching habits with an accuracy that was almost scary.

The first video ("skateboarding bird") and its "nudge to swipe" were perfect, which kept me engaged enough to—

Once I was hooked, sponsored ads started to sneak in and…

…each addictive "swipe up" felt more and more like I was pulling down the handle of a slot machine

…which made TikTok's "digital wellbeing" poke feel like false empathy. A simple tweak could've made the experience more Humane.

👋 Got a question or some feedback?

We're just one reply away on Twitter.


PS: Yes, we reply to everyone.

🎉 Congrats! You found the secret slides!


You completed Growth.Design's Case Study #023:
"The Psychology Behind TikTok's Addictive Feed"