>‘Brain rot’ is defined as “the supposed deterioration of a person’s mental or intellectual state, especially viewed as the result of overconsumption of material (now particularly online content) considered to be trivial or unchallenging. Also: something characterized as likely to lead to such deterioration”.
Trivial / unchallenging is not the problem, in my opinion. Sometimes it's good to relax and give yourself a break. Staring at the wall and letting your mind wander is trivial and unchallenging, but it's not going to rot your brain.
The problem is overstimulating shortform content that wrecks your attention span.
But I don't believe super-longform content is necessarily the solution, either. If you force yourself to think about the same thing for too long, it effectively becomes work, and generates the same sort of mental fatigue. That's sort of pointless if you're trying to relax and recover.
I think it's best to aim for a sweet spot of "unchallenging and also understimulating".
I don't think you necessarily disagree with the definition. You mentioned "Sometimes", while they explicitly said "overconsumption". Most things are ok in moderation, including stupid relaxing.
I think what the definition fails to capture is the addiction-like behavior that this specific kind of content can induce. You feel yourself getting more tired and frustrated by the minute, yet you don't stop.
Its a definition, not an encyclopedia article or something. The definition of alcoholism probably doesn't go into the ways people fall into alcoholism either.
>Most things are ok in moderation, including stupid relaxing
For real. Sometimes, I think that the binary nature of language, things are either good or bad, there is no single word to describe n-shape dose responses except in aphorisms like "too much of a good thing", means that it's too easy to autopilot into thing A is either good for you, or bad for you. One beer with friends is good for you but ten is not. The optimal amount is somewhere between (it's slightly less than 2).
Just do what we've done since the dawn of time: hang out with friends and family, prepare and eat food together, maybe play card or board games. It feels good and it's good for you.
That's actually not that easy to do when people are expected to be living alone at a certain age. Finding a partner could be good for you but that's also not so simple. I think most people would prefer hanging out with others rather than scrolling tik tok (you might enjoy alone activities but tik tok scrolling comes out of boredom), but sometimes they have no choice. It's like the way we live is pointing us specifically in that direction, at least by default.
You don't need to be in a relationship to hang out with people. I think the issue most people encounter is that hanging out with friends suddenly gets a lot more difficult after education ends. The people you meet at work are less likely to become close friends than the people you meet at school, and as people get older, they have more responsibilities that take up their spare time, and fewer options to just spontaneously hang out.
In addition, traditionally, men tend to rely on their partner for non-professional social networking. The percentage of people who live with a spouse or partner seems to be decreasing, so men are becoming more responsible for maintaining their own circle of friends.
This requires effort. It's not like when you're 18 and you just naturally hang out, you have to put work into maintaining friendships and finding ways to meet. You have to plan things and invite people. You also have to make new friends as old ones disappear from your life over time. This is difficult, it requires conscious effort.
I didn't realize that for a long time, and the longer I didn't do it, the harder it became to reestablish old friendships and make new ones. But it's absolutely possible to do it, if you put in the effort.
And it's very worthwhile. It's much more enjoyable and fulfilling and relaxing to cook with somebody, go for a walk, or play Mario Kart in person, than to scroll Instagram or play an online shooter.
> I think most people would prefer hanging out with others rather than scrolling tik tok
However both introversion and the hedgehog's dilemma can complicate this presumption. I think I'd rather say that most people would prefer hanging out with others in some fashion where they are safe from constant drama .. but the reality is that getting along with other people — including close friends and perhaps especially family members — takes a lot of effort and emotional labor.
With our current ubercapitalist society (definitely in the US but it affects the rest of the globe as well) and poor social understanding of mental health, many of us simply lack the resources to constantly expend said emotional labor and connections often fall away as a result.
> I think I'd rather say that most people would prefer hanging out with others in some fashion where they are safe from constant drama .. but the reality is that getting along with other people — including close friends and perhaps especially family members — takes a lot of effort and emotional labor.
Not the person you replied to but most of the things I do in my free time are somewhat challenging and stimulating. Programming on something that is very new to me and outside of what I do in my job, a challenging video game, hobbies that do involve my computer (got into 3d modeling a while ago) and hobbies that don’t involve my computer (leather working as of quite recently).
I also used to learn languages for fun but I figured out really quickly that I like linguistics more than languages so I can be a real smart ass about grammar in various languages but couldn’t order a beer in most of them.
I get really annoyed and in a really bad mood if I just watched a movie after work and went to bed. Or just hung out with people. I don’t feel like I got that itch taken care of if I don’t get an hour or so at night for the side projects.
Oh and none of this is monetized. I can and do drop projects as soon as they get boring.
I think you're referring to another phenomenon that leads mostly to apathy. "Brain rot" as it's described leads to a change in perception, and I wonder if it also changes beliefs.
"Brain rot" seems to be linked with the repeated consumption of, for example, unchallenged propaganda.
It encourages people to think they made some huge insightful breakthroughs, and that they have some new undisputed understanding of reality, when in reality they just have a superficial knowledge of someone else's idea. Which sometimes is amplified by someone repeating someone else's ideas. Yet they refuse to either acknowledge or question it.
For example, unlike general perception, conspiracy theories aren't that complex, they're much simpler than reality and more entertaining - as an anecdote it's much simpler to think the moon landing was done in a Hollywood studio than to understand the endeavor taken to achieve this milestone for Humanity.
This leads to people dismissing reality in favor of fantasy, leading to algorithmic thinking, which is just a lazy cognitive process. If you challenge this, you'll be ignored or dismissed.
>It encourages people to think they made some huge insightful breakthroughs, and that they have some new undisputed understanding of reality, when in reality they just have a superficial knowledge of someone else's idea. Which sometimes is amplified by someone repeating someone else's ideas. Yet they refuse to either acknowledge or question it.
This could also describe a mediocre student reading a mediocre physics textbook.
I'm not sure consumption of propaganda is qualitatively different from consumption of non-propaganda.
> This could also describe a mediocre student reading a mediocre physics textbook.
I think you're being too generous. It's more like a mediocre student listening to someone's take on a mediocre physics textbook and believing now that he knows how the world works.
The difference between the consumption of propaganda and non-propaganda, is related to the perception of everyday events and the consequences of it.
In your mediocre student example, his unacknowledged poor understanding of physics won't have much consequences, he can try to lecture people, and he can go about the world and unless he tries to defy laws of physics there won't be much to it - like a "flat earth believer" can have a boat ride and not fall off the earth.
Propaganda, on the other hand, changes your perception of reality and the way you interact with society and institutions. Suddenly, a normal election process is rigged because your side lost, or the normal vaccination process is now harmful to you and your peers.
Is there actually any evidence that an “attention span” can be affected in any way? I’m not knowledgeable about any psychological studies on this topic. My instinct says that young people consume short form content because that’s their preference. I’m sure they’re also still capable of like watching a movie.
Yes, there is. (Mind you, I'm not a psychologist, this is just from a quick online search.)
There's a study from 2012 linking social media usage to reduced academic performance and a lowered attention span [1]. A recent study has shown that excessive TikTok use in particular is linked to short-term memory deterioration [2]. I assume this is a somewhat trendy field of research in psychology, so you can likely find more studies, should you want to.
i've met countless people who aren't capable of watching a movie, they just sit there looking at their phone the whole time then claim the movie was stupid and/or boring and that they "didn't get it". if you ask them what a good movie is, they say something they liked from before they became phone addicts because they literally haven't watched a movie since.
i also personally struggle a bit with older movies (80s/early 90s) because they tend to have a slower pace and i instinctively want to start multitasking every time there's a lull in the action. i actually watched die hard for the first time last night and found it kinda slow and boring despite it being one of the most iconic action movies of all time.
there may or may not be a scientific study to suggest it can happen (although i assume there is) but based on my own experiences i am 100% certain that it is happening.
> and [I] instinctively want to start multitasking every time there's a lull in the action.
That's your cue for an attention problem right there. For the fun of it, try to notice in how many other situations you might have the same tendency to look for a "multitasking" distraction.
I've tried watching classics like the old Lynch take on Dune or 2001, and I couldn't finish them; I don't believe it's entirely down to phones / tech-induced attention deficit, but simply due to different filmmaking styles of the time, where I presume visuals and the experience had a much higher impact on their own. As someone else metioned, Villeneuve's films echo these slow burners, but they're a bit more modernised. But, I need to make time to watch films like that, ideally on my own because in a house with family and youth with both clinically diagnosed ADHD and a chronic youtube/tiktok/gaming-with-voice-chat addiction, getting three undisturbed quiet hours to myself is difficult.
A good litterature survey, easy to follow. Better than reading one or two isolated studies, since it does ask the crucial question of "well what is (and how do you measure) attention span anyway?"
I'm not personally aware of academic study of this (and haven't looked, admittedly,) but my experience and anecdata from others I've known says that yes it can be very affected --our attention spans are malleable and affected by our environment. When I've been going hard on (overstimulated by) low-attention span content like social media, video games, certain video content, it has a pronounced impact on my ability to focus on things longer term.
The best example is reading a book. I end up having to reread sentences and paragraphs frequently as my mind wanders from what the words are conveying. It takes a while to get into the groove of following the thread of the writing. Spending some time in a less stimulating environment like going camping, practicing meditation, or just 'unplugging' seems to be restorative to that ability to focus. Other people have shared similar experiences with me many times as this subject comes up.
Again, my experience, but this capacity for focus applies to many things beyond just reading a book, like tackling programming problems or having a deep and nuanced conversation, effectively communicating complex ideas and being able to receive the same.
All i've really got is personal anecdotes, but i've noticed that excessive scrolling (~consuming short form/attention grabbing content) in the evening/morning correlates negatively with my ability to focus on longer, less dopamine-rewarding tasks.
This usually goes away after a few days of reducing said behaviors, so it seems at least mostly temporary (the same might not be true in teenagers or younger)
An anecdotal one that was first published over 20 years ago (but updated for modern-day distractions) is here: https://randsinrepose.com/archives/nadd/. I'm sure it was updated anyway because it references stuff that didn't exist in 2003 yet, like Twitter, but the oldest internet archive version from 2014 seems to have the same contents. If anyone knows where the original is, do comment. But anyway, he also did a follow-up about watching films without the attention span, in 2005 already: https://randsinrepose.com/archives/movie-nadd/
Interestingly, he posits that the opposite is "information overload"; people who can't skim or skip things who are still exposed to too much input and break down for it. Of course, I want to believe this is a choice, you can turn off your phone and notifications, set up a system of critical notifications that cannot wait (which when you think about it is very little, or it's another person who has a problem with needing quick replies).
Yes, I'm not so sure that they are capable of watching a movie. I tried to watch TV with my sister and failed because she spent the time looking at her phone.
In any case, if watching a movie is the counterexample it is probably in the category of "damning with faint evidence". This is still passive media which carries on whether or not the watcher is attending. Reading a book for an hour or two is different, because the pages don't turn themselves.
People in a position to notice changes in these capabilities have noticed them.
It does not matter what the actual effect of this type of content is - it makes people feel in a specific way, so they started using "brainrot" to describe what they are feeling.
Am I crazy or should it be "brainrot" (no space)? I'm actually not bothered by the idea of word of the year having spaces, I just thought this particular term had no space.
I'm glad to see this word getting wider exposure. I hope people will expand it's use to describe all kinds of content beyond the narrow/extreme aesthetic it refers to in short form video. Once you start looking, you recognize brainrot content everywhere: daytime TV, talk radio, reality TV, cable news, Facebook AI slop, etc.
On the topic of brain rot, content creators with longer form videos often include a video playing in the background which has no relevancy to the narrated content.
The video itself isn’t necessarily brain rot content but rather a side effect of a majority of people’s short attention spans.
In some cases, the content can include relevant video content but split viewed with something irrelevant (ie, random subway surfers gameplay). It’s quite annoying and distracting for me.
A lot of those are actually spam accounts that repost popular content with an extra video in order to still have enough apparent originality to get paid.
The split view subway surfers thing is definitely brainrot content, it's often retelling a story from Reddit or Twitter but since a voice reading something out isn't stimulating enough (nor is reading it) they add visual distraction. A lot of non-brainrot content still has something in it though, jump cuts so you getSentences that kindaSound like this butWritten out toGet more words inLess time, camera changes, background music, graphics, etc.
There was an AI news/analysis channel that I had to unfollow because of this. The guy did a good job distilling down the news, but half of the length of each video would be random AI-adjacent videos (like footage of someone testing a drone or a self driving car) that had nothing to do with what he was talking about, and I found it difficult to focus when I couldn’t be sure if the stuff on screen was supposed to be relevant or not (he’d often cut to charts or samples of a video output).
Lately in slop-land I’ve also seen shorts where the creator will take an old boomer joke (one of those “and then the student stumped the teacher” kind of stories) and have an AI voice read it while the video is cuts from “satisfying animations”-genre videos.
Political brainrot is arguably the most sinister because it trains people to abandon logic and base all of their beliefs on feelings. And there is a huge incentive for companies to inject this into discourse to polarise and swing people one way or another.
I've watched American TV a few times, over ten years ago now, it was definitely brainrot-like in that there was a lot of repetition, visuals, and smooth / uninterrupted transitions to frequent ads. I don't believe tiktok was the one that introduced it, it started decades before. Pre-TV people would get a stack of newspapers and only skim the headlines.
Can't forget video games, video game streamers, variety podcasters, pornography, sports tv and sports commentary, edutainment, documentaries, cartoons, comics, fanfic, romance novels, action movies, Vince Flynn books, political masterbation such as Last Week Tonight and Sean Hannity, news farms like NYT and WSJ, or smoking weed.
You chose a cross-section of content that that is universally derided by the average HN user; if you're not willing to use the front facing camera you're just taking potshots at your outgroup.
I mean I came up with the list by going through the kinds of mindless passive entertainment that has little to no to negative intellectual or artistic value that either I or my coworkers (who are mostly Dads hence Vince Flynn) enjoy that I think intersects with HN types.
It's easy to call out the kinds of low-value activities that you don't personally enjoy or partake in. It's a lot harder and more uncomfortable to see them in yourself and have some empathy and not judge others too much for their brain-off vices.
Only when I die and see the big stats board do I want to know how many hours I've wasted on Slay the Spire. And while I love it dearly I can't really delude myself that it's anything other than Candy Crush for nerds.
You do know that there exist more games than just candy crush? There are many games that I personally would order in the same magnitude of culture importance than musical symphonies. Portal 2, World of Warcraft, The last of us, Breath of the wild, just to name a few.
It's always video games that strikes a nerve with people on the internet. Yes I've played and beaten all the games you've mentioned. Sure artistic video genres exist just like artistic porn exists but we're not meaningfully engaging with the activity as it really exists by pretending that's what I'll find if I go to xvideos.
I've sunk 16k+ hours into WoW in my lifetime, you named perhaps the most brainrot game that has ever existed in the history of video games. It's makes Tiktok look like long form essays, doing meth instead would be considered harm reduction.
It's easy to identify when the activity is low status to your in-group. The Big Bang Theory has significant cultural importance but I bet you'd agree it's still brainrot.
Video games are probably the least bad here considering most of the popular ones are like 100 hour stories and are usually played in 1 hour chunks. Not the typical short form brain rot.
It really depends on what your definition of "the popular ones" is. One of the most popular games is Candy Crush, which is not a 100 hour story game but fairly quick mobile activity game.
On the other side you have Ubisoft's genre of "brainrot" games, which on the one side will have a compelling story, but on the other will have hundreds, if not thousands of similar repeating side-activities that people can jump in and out of without needing to think too much.
And on the other other side you have story-rich games, e.g. God of War or RDR 2, which have a film-like setup and budgets to match.
Being long doesn't necessarily mean they aren't bad for attention spans. I recall seeing a reviewer complain about a story driven game recently where the characters were constantly restating plot points to make sure you didn't forget. And the more important thing in games than narrative, I think, is how much the gameplay itself makes you think long term (or not), and the pace of things. Do you have to keep a goal/strategy in mind or just constantly react to what's immediately in front of you?
I‘ve been using brainrot to describe content since about 2016, but apparently its been used as early as 2003 online to describe shows like The Bachelor. Brainrot is everywhere, even among what one may consider “high culture”. The play Hamilton is a prime example of this. Theater is regularly considered high culture, however due to a combination of poor historical accuracy, oversimplification of the events involved, and, in my opinion, very commercialized sounding music, leads to what is very effectively “high culture brainrot”.
I am not familiar with either, so this was hardly the “gotcha” you may have expected. If you have disagreements with what I posted I urge you to actually focus on said post rather than whataboutism.
You seem angry that a play is historically inaccurate. I am curious if it's because there's something special about the American Revolution to you that perfect historical accuracy in a musical is required. Seems like a strange thing to find sufficiently frustrating as to call it "brain rot"
Historical inaccuracy was simply one of a handful of points I made, and I am hardly “angry” that a brainrot musical, written by a man with no historical background, was inaccurate. Additionally, I am willing to suspend my desire for accuracy for certain plot-related reasons, for instance there is no historical backing behind Angelica’s infatuation with Hamilton, but plotwise it created a compelling, albeit poorly expanded upon, narrative.
The definition of brainrot is, in my mind, something that you cannot learn from and may even teach you misinformation. Hamilton’s lack of historical backing and poor narrative lead to a situation where it fails to teach you history or have an in-depth story worthy of inaccuracies. They essentially took the setting of late 18th century Boston, put a slew of modern-thinking historically-named figures in it, and wrote a simple story using those caricatures. Add in very inconsistent “hip pop” music, leaning into simpler choruses that paint in large strokes, and it’s no wonder that it achieved mass appeal. That’s simply how brainrot works. Less cognitive processing required means that its easier to digest and share. It’s also why “low culture” contains fart humor and why “high culture” contains books such as Don Quixote.
I've noticed that younger fellows like to correct people while using the crying emoji, and point disturbing stuff with the skull one. Tears of joy is probably not ironic enough for them.
I'm seeing some confusion in the comments as to whether 'Brain rot' is one word or in fact two words.
'Brain rot', in the context of this slang term, can be considered one word.
Despite that you can technically split 'Brain rot' into 'brain' and 'rot' (which are both words), 'brain rot' isn't actually the sum of its parts and has a more idiomatic meaning than just 'brain' + 'rot'.
That's not what the comments are about - they're noting that the cohort popularly using this term spells it "brainrot", so it's odd that Oxford picked a different spelling.
You sniped me. The internet seems to agree with you that the current usage of "slop" was popularized on 4chan in 2022, but it's been around way longer. I've always known slop as the food scraps served to pigs.
As someone on Mastodon observed [1], it's also got all sorts of great resonances with words like "slime", "sleaze", "sludge", "slug", "slither", "slouch", etc. The word itself implies a distasteful, slippery (another sl- word!) nature.
I know that they don’t literally mean a single word, but it got me thinking: is a space ever a valid character in a word? I’m guessing no, because that’s fundamentally how languages separate tokens
However, while I’m no language person, I have wallowed in unicode enough times to recognize that the “rules” of language are so wild and varying and riddled with exceptions that basically anything is possible.
Yes: an open compound has two words separated by a space, but still has a unique meaning. Ice cream, common sense, never mind, etc.
FWIW, there are plenty of languages that don't use any spaces at all in their writing (Japanese, Chinese, Thai), and the use of spacing is quite fluid even in English. Is it a cellphone or a cell phone?
So technically in linguistics, the spoken language is considered the ground truth while the way the language is written is just a crude representation of the spoken language.
What this implies is that a space being used between two tokens doesn't actually make it two words. You can still consider that to be one word.
(Also, if you wanna go even more meta, there isn't even a widely agreed upon definition for what a word even is in linguistics!)
> (Also, if you wanna go even more meta, there isn't even a widely agreed upon definition for what a word even is in linguistics!)
To be even more precise, there are several competing definitions of what "word" should mean that don't always agree. E.g. if you go by the criterion "word" = lexeme (dictionary unit), then something like "kick the bucket" would be a "word".
No, "se" here is Latin in the same way that "exempli" and "gratia" are. You similarly can't use "kung" or "fu".
That said, you may not like this answer, but ultimately whatever's in the official dictionary (now known as Collins Scrabble Words / CSW) is what goes. "mein" as in "chow mein" is not valid (nor is "chowmein"), but "lomein" and "wonton" are.
Space is arguably the absence of a character. It is only a character for creating encoding standards in computing systems (*or actually since the typewriters).
The practice of placing spaces between words is connected to writing, so not some fundamental part of language. There are early Latin texts that don't have word dividers at all, for instance, and some languages used different symbols like dots.
At least in English (I don't know other languages well enough to speak with any any kind of knowledge) whenever you want a term containing 2+ words meant to be taken together, you use a hyphen. Compound words, I believe they are called.
From what I can tell, they should have spelled it brain-rot.
One minute on Wikipedia would have disabused you of that wrong notion:
> If the joining of the words or signs is orthographically represented with a hyphen, the result is a hyphenated compound (e.g., must-have, hunter-gatherer). If they are joined without an intervening space, it is a closed compound (e.g., footpath, blackbird). If they are joined with a space (e.g. school bus, high school, lowest common denominator), then the result – at least in English – may be an open compound.
A general heuristic is: single word is the noun form (e.g. "I made a backup"), two words is the verb form (e.g. "back up your data"), and hyphenated words is the adjectival form (e.g. "the back-up copy is over there").
Yes, many words that started out as two words separated by a hyphen merge to become one as language evolves. Notebook is a good example of this; a more recent example would be email.
Funnily, I started using this word when I'm referring to social media, the addicts of daily TikTok and Instagram scrolling users. Maybe I'm exposed to this brain rot, since I am using this word lately a lot, and possibly, I picked up unconsciously from other sources.
I would bet that at Oxford the word that is most important, but never spoken out loud is "relevance"
which they are grasping at
A good part of this thread just ignores there "naming" and gets on with having fun with language, without them.
It is funny that certain niche circles complain about the hive mind virus or whatever and that is by this definition a kind of brainrot to be complaining about that! Too funny.
Enshittification was an indictment of for-profit social media, but they're already irrelevant as they've been out-competed by state-sponsored social media like tiktok and twitter.
Different concept. Enshittification implies an original state that is better. Meanwhile, most of the stuff that we consider brainrot are actually pretty well made.
Well, it should be, but you've made it one. "Thats" actually stands for "that" and "is" so "that's" would be the correct form. You're missing an apostrophe.
amidst societal concerns about the negative impact of overconsuming online content.
Yeah sure there's concern but it's only about what the other side is consuming. We're not applying the concern holistically and probably won't be able to because that would mean threatening the companies that host said brain rot and we just can't have the shareholders mad.
Agreed, it's not really a political term (if that's what GP is implying). Translating into millennial/Gen x speak it's the sort of meme that you'd see in YouTube Poops a decade ago (or today, I guess)
Can I coin some new relevant word(s) for 2025: Billionaire's disease / billionaireitis / ventureitis
Basically same as Nobel disease / nobelitis, but applied to wealthy (often tech) billionaires. Where after a certain amount of success in a quite narrow field, they start to push broad and wide-reaching ideas, which go far, far beyond their expertise.
I'm not going to name names, but there are plenty of such billionaires out there, some getting far too much media time. Some even showing signs of advanced brain rot due to the media they consume.
"Prince has been living in Prince-world for a number of years now" (possibly misphrasing of a sentence from Kevin Smith's recollection of his experience working for Prince).
Sycophantitis. For which the treatment is a Messianectomy.
So was Trump, and trump clearly knew about Epstein's "preference for girls, especially of the young kind" circa the 2001 vanity fair article where he was quoted saying that.
I've thought of something similar, maybe call it "techbro poverty"
It's sort of like chesterton's fence + branding + fashion + stupid optimization giving us dystopian product design that any normal engineer understands is stupid.
There are lots of examples of this:
- remote controls with terrible play pause skip buttons, but big oversized dedicated buttons for some product they want you to use.
- cars with no dashboard, no dedicated buttons, no turn signal stalks and everything on the touchscreen
- laptops with no ports and terrible flat, unsculpted keyboards.
- phones with no dedicated buttons, or buttons you can only dedicate to payment systems
And the best thing about comments like this is that because ‘experts’ in this situation includes thousands of people it only takes a mistake from a handful for this statement to be seen as accurate by the lay person.
It’s like arguing that ‘experts’ in IT have no clue what they are doing because of a mistake made by IBM failing to deliver a government contract.
No, it's not like one expert was wrong, they were just literally wrong over and over about everything - it was pseudo science galore all the way. But people have short memories.
Trivial / unchallenging is not the problem, in my opinion. Sometimes it's good to relax and give yourself a break. Staring at the wall and letting your mind wander is trivial and unchallenging, but it's not going to rot your brain.
The problem is overstimulating shortform content that wrecks your attention span.
But I don't believe super-longform content is necessarily the solution, either. If you force yourself to think about the same thing for too long, it effectively becomes work, and generates the same sort of mental fatigue. That's sort of pointless if you're trying to relax and recover.
I think it's best to aim for a sweet spot of "unchallenging and also understimulating".