The Science of Six Degrees of Separation
The Science of Six Degrees of Separation

I have a friend named Sammy who back in the
early 2000s wrote some code for his MySpace page. And what the code did was anybody who
visited his page would have his picture and a tag line that said, “Sammy is my hero,”
copied over to their homepage. And that was a bit of fun for a while, but Sammy wanted
more. And so he tweaked his code so that no only the picture and the tag line were copied
over, but also the code itself. And now it exploded. In just nine hours he had reached
480 accounts. In 13 hours he was up to 8800. And in just over 18 hours he had hit a million
accounts, which was a full 1/35th of all the accounts on MySpace at the time. So in a panic,
he tried to delete his page. And when he was successful he actually took down the whole
of MySpace with it. He was arrested and convicted of computer hacking and ordered not to touch
a computer for the next three years. But I think what this story really tells us is just
how connected we all are. Imagine you have 44 friends and each one of
those friends has 44 friends who are not also your friends. And each of them has an additional
44 friends, each of whom has 44 friends who again has 44 friends and they have 44 more.
Then in a chain of just six steps you would be connected to 44 to the sixth or 7.26 billion
people, more than are alive on earth today. And we have contemplated how closely connected
we area since long before MySpace even existed. Back in 1929 a Hungarian author and poet named
Frigyes Karinthy wrote a short story called Chains. And in it, one of the characters challengers
the others to find another person on earth that he cannot connect himself to through
fewer than five intermediaries. This is the origin of six degrees of separation. If the theory is correct, it means that you
would be connected to the Queen or Tom Cruise in just six steps. But they may be the easy
ones. What about this shop owner or the Mongolian sheep herder? What the theory really means
is that any two people picked at random from anywhere on the earth would be connected by
just six steps. The idea remained just fiction until in the
1960s a Harvard psychologist, Stanley Milgram, attempted to test it. He called it the small
world experiment after that phenomenon where you are at a party, you meet a stranger and
you find out that you have a friend in common and you remark: Oh, it is such a small world.
What he did was he sent out 300 packages to people both in Boston and in Nebraska. Now
what he wanted those people to do was try to send their package to a target person in
Boston, but they weren’t allowed to send it directly to him. They had to send it to
someone they knew on a first name basis who they thought had a better chance of knowing
the target and they could forward it on in the same way. Now, as you might expect, most of the packages
never made it, but 64 did and the average pathway was 5.2. So now six degrees of separation
had experimental confirmation. Or did it? If you look more closely at Milgram’s sample,
you will find that of the 300 people, 100 were located in Boston, the actual city where
the target lived. Another 100 were stockbrokers, which was the same profession as the target.
So only 100 people lived in a different state and had a different job. And of them only
18 of their packages made it to the target. So we are talking about a sample size of 18
is all the evidence there was for six degrees of separation. So experimental evidence was tough to come
by. But a decade earlier, a mathematician named Paul Erdos had tried to work out the
theoretical properties of networks like these. But he didn’t have any information on the
structure of real social networks, so he decided to work on networks where the connections
between nodes were all completely random. And we can actually simulate a network like
this using buttons and thread where we just connect up the buttons at random.
What Erdos found is that when the number of links per node is small, the network is fragmented.
Pick up any button and few others will come with it. But once you exceed an average of
one connection per node, the behavior the network changes dramatically. They almost
all link up forming a giant cluster. Now if you pick up any button almost all of the rest
will come with it. This change happens rapidly and it resembles a phase transition in physics.
Now you could call this a small world network, since the path between any two buttons is
short. The thing about random networks is that they
are naturally small world networks, because you are just as likely to be connected to
someone here in Manila as you are to someone in your own town. But obviously a random network
doesn’t represent real life very well. So what do real world networks look like? Well,
for that, we need to go to the empirical data. In 1994 a couple of college kids invented
a game called six degrees of Kevin Bacon in which you try to connect any actor to Kevin
Bacon through just six steps through his costars. Now a couple of sociology researchers got
access to their database of a quarter million actors and they analyzed the network and what
they found was that it was a small world network, meaning between any two actors there were
only a very small number of steps. And that is very similar to a random network. But unlike
a random network, the actor network also showed a high degree of clustering, that is, they
often worked together in small groups. So how do you get both this grouping behavior,
a high degree of clustering, and the short number of steps between any two actors? Well,
to figure this out they looked at two different extremes. Imagine a circle of nodes. Now if
you connect them at random you get the same outcome as Erdos, short paths between any
two nodes, but little clustering. Now consider connecting up the nodes only with their nearest
two neighbors on each side. Now clustering is high, but path lengths are long for two
nodes picked at random. But what if you take this set up and rewire
just a small number of connections randomly. What you find is that the path length drops
rapidly, but clustering still remains high. So the key to modeling real social networks
is to have a lot of clustering behavior—that is, your friends are also friends with each
other—but also to have a few random acquaintances. And the importance of those acquaintances
can’t be overstated. There was a researcher named Granovetter in
the 1970s who published a paper called “The Strength of Weak Ties,” in which he points
out: You are much more likely to get a job through those random acquaintances than through
your close friends. And if you think about it, that makes sense, because you and your
close friends all know the same people and have the same information. It is through the
random acquaintances that you can get connections with people very far from your social circles.
So you can find new jobs, new places to live and you can be connected to the outside world. So, in fact, it is those random acquaintances
that make possible six degrees of separation. So when I want to…>>I am told the degrees have dropped in recent
years.>>Really>>…to like four degrees.>>Tell me about that. How do we know this?
>>I don’t know how they measure it, but I have tested it and I think it actually has
dropped based on how many people have friended one another on Facebook. The friendship circle
has grown, not that they are bosom buddies, but they are people you have access to. That
is the point.>>right.>>And it is… do you know this person who
then knows that so that I have access to these other people? So I am told that it has dropped.
As much as the six degrees, we are down to four, at most five.>>I think Neil DeGrasse Tyson might be right.
In 2011 Facebook analyzed their data and they found that 92 percent of their users were
connected through just five steps. And that number is decreasing over time.
The concept of six degrees of separation has fascinated people for nearly a century. And
I think that is not only because of how counter intuitive it is, but also how comforting it
is to know how closely we are all linked, not in some kind of abstract, ill defined
way, but through hard scientific data. Just six handshakes will connect you to anyone
else on the planet. Now I have a challenge for you. In the spirit
of six degrees of separation I want to try an experiment. I want you to try to get an
email to me. But you can’t send it directly to me unless you know me. So assuming you
don’t, I want you to send it to a friend of yours, someone you know on a first name
basis who you think has a better chance of getting that email to me. If your email eventually
gets to me through a chain of people, I will send you a postcard in the mail and I will
tally up if we were able to get that done in six links or not. So let’s try to do it and see if we can
connect. The instructions are in the description. This episode of Veritasium was inspired by
the Fine Brothers, Ben and Rafi Fine who are friends of mine. So we are connected through
just one degree of separation. Now they have a brand new TV series launching on TruTV.
It is called The Six Degrees of Everything and it is a fast paced comedic show that tries
to show us how six things that we don’t think are connected actually are. It involves
sketch comedy and songs and reality TV. I am really looking forward to seeing how they
are going to do this. So you can check it out Tuesdays at 9:30 or 8:30 central on TruTv.
I am so looking forward to it. And thank you to the Fine Brothers for sponsoring
this episode so I could check out the science of networks.

100 thoughts on “The Science of Six Degrees of Separation”

  1. tagosadilim says:

    OK. I'm looking for a job now.

  2. Candi Soda says:

    4:32 I want to be those two buttons -_-)

  3. John L Tee says:

    That is in Manila 2:07

  4. Watashiwa Ldes says:


  5. anglo2255 says:

    Only one degree of separation. Everyone is a 10 th cousin twice removed or some degree of cousin

  6. GuinnessandPizza says:

    Sooooooo….how did the email experiment go?

  7. jopageri1964 says:

    My meeting Kevin Bacon ten years ago was quite liberating. From then on I never had to worry about any degrees of separation with anyone or anything.

  8. simonlb24 says:

    I have an old friend who has met both David Cameron and Theresa May (both former UK prime ministers), so that means I'm two degrees from The Queen.
    Unfortunately, that means I am also only three degrees from Donald Trump. Now that I think about that, I am seriously conflicted.

  9. Annika Kaelin says:

    Sailing has a lot of clustering with people you are close friends and sail with but you meet and know a ton of people through sailing so I know and recognize many people that I see at regattas so that has a very small degree of separation through the sailing community

  10. Giorgio Napoli says:

    0:40 someone forgot a jacket on the bench!

  11. Krishna Batabyal On KSB GAMING says:

    My best friend is a desk. Go figure

  12. Clubcatz says:

    it's pronounced "air-dish"

  13. Ane Mari says:

    2:03 is that divisoria in the philippines? Hahaha

  14. Stéphane Bigalet says:

    For your information The French President MACRON said on television that it took 6 generations to reach the middle classes. This also implies 6 more generations to reach the upper classes. So 12! Like the apostles. Friendship, Stéph.Pour votre information Le Président Français MACRON a dit à la télévision, qu'il fallait 6 générations pour arriver aux classes moyennes. Ce qui suppose aussi encore 6 générations pour arriver aux classes supérieurs. Donc 12! Comme les apôtres. Amitié, Stéph.

  15. MouseInverted says:

    44 friends?
    I have like…. 4


  16. Acke Brocke says:

    That samy dude is cool

  17. Tomtastic's Videos says:

    My dads boss is friends with Donald Trump and that connects me to Kim Jon un Putin, All the politicians and so many more lol

  18. D3athangel1 says:

    4:33. The moment that the guy in the blue Nike Kobe shirt figures out what the hell is going on with this weird guy in plaid gesturing and talking to nobody in the middle of the marketplace.. and then decides to step out of the shot 😀

  19. Βασίλειος Μπεσλεμές says:

    you random viewer!

    I know a guy
    who knows a guy
    who has a sister
    who knows a guy
    who married a woman
    who knows where you leave,
    so be aware

  20. Avilaas says:

    well… the first problem: I dont have 44 friends

  21. XERO MECHANICS says:

    I made 999 to 1 😁

  22. Kaspos Blazos says:

    There's these two swedish television personalities that made a show to try this concept. In one episode they started out in a small remote village with no water or electricity in the desert in Namibia, they choosed a old lady as the first person in the chain and managed to connect her with Michael Bolton in just 6 steps. They start by asking the first person if they know someone who might get them closer to the target (michael bolton in this case) and travel to that person and continue doing the same til they get to the target. The lady knew a guy that worked in the tourism industry, he knew someone in Isreal, and so on. In another episode they connected Gordon Ramsay with a old lady in a remote village in Nepal. Its amazin how this actually worked on several people in just 6 or7 steps. The show is called "Jorden runt på 6 steg" hosted by "Filip och Fredrik"

  23. BBM says:

    Degrees of separation should get smaller due to the size of your network. Small equals smaller degrees. Does it make sense that the degrees of separation get smaller the longer certain folks are alive/live longer? Too many variables there Tyson.

  24. Mogul DaMongrel says:

    Nobody cares about network popularity. Itts already been proven that massive amounts of attention can be artificially generated by the creation and implementation of bots. I dont know why your opening statement to this concept involves anything on this heavily artificial platform of faux trends and bloated views. Im not even going to bother with this video. Just dumb

  25. Life Connoisseur says:

    What if you have absolutely no friends?

  26. tudorjason says:

    How did a court of law convict Samy of hacking when his intention was to only delete his account, despite the payload attached to his code? The concept of deleting one's own account doesn't scream "bring down a site". This situation should have been based on intent, or a lack thereof. Perhaps it was Tom's fault for not building a secured-enough website. The court obviously didn't know what hacking really meant still, despite the fact that Hackers was released nearly a decade earlier. Samy's conviction should have been overturned and him given a settlement for the trouble he had to endure because of others' ignorance.

  27. josh fixall says:

    There's a lot of comments but I don't think anyone pointed out he love tapped the girl in the beginning (or got super close)

  28. Mark Reedman says:

    Amazing form of block chain

  29. Clayton Heathscott says:

    Dudes walking past you while you were talking were trying not to laugh there ass off

  30. A Boy and Philosophy says:

    the mass

  31. Sammy Spaniel says:

    This means I can start name dropping with a clear conscience.

  32. nooneknows says:

    lol i have 4 friends

  33. Paul D Pearce says:

    facebook is an amazing tool for this …. I've lived in 4 places and have many friends that are interconnected on FB ! I have found friend from kindergarten through a friend from high school and have discovered many other connections

  34. breezebro says:

    I always wondered how I got so many Facebook friends.

  35. D says:

    Me, my friend, the president, (random world leader), their friend/colleague, random peasant farmer in random communist country.

  36. 123jerro says:

    Quite a pickpocketing problem in Manilla seems LOL

  37. Jack Gordon says:

    I want to know why he filmed this video in Manila and Melbourne and why he wore the same outfit in both locations.

  38. Dave Grenier says:

    The package experiment was flawed. It depended on the judgment of the people sending the packages along. In the less-successful group of package handlers, being the most distant from the targets and having the least in common with them would have been less able (than the more successful group) to judge to whom to send their packages. An error in judgment anywhere in the chain could the prevent the package from coming through to the target even if a successful (but unknown) chain existed. With similar groups of people (stock brokers, doctors, attorneys, etc), errors in judgment play a lesser role because the participants' (i.e. everyone handling the packages) are more likely to send the package along to someone who is capable of maintaining the chain by chance. So we should expect people with a strong common connection (college, military service, occupation, etc.) to have more success. The connections between people who have things in common are denser, so even random jumping from one person to another could have success in getting the package to a target individual even if no previous chain between the package handlers existed.

  39. maverick0698 says:

    HOW do you just start talking to a camera while dozens or more people stare at you like you're some weirdo? lol

  40. stretch se7en says:


    6 to 1 as in "MOST TO LEAST"

    "NEIL." !? At the MOST?! "FOUR"
    /social media/

  41. Kaleb Bruwer says:

    That cluster model isn't bad, but I think it needs a tweak: You are in multiple clusters. Very few people are in more than one cluster with you, but you are connected to everyone in every cluster. So instead of a handful of out-of-cluster connections, you have slightly overlapping clusters, if that makes sense.

  42. im1who84u says:

    7:02 That guy either needs to tuck his shirt in or untuck his shirt in.

  43. PeteLazada Minecraft says:

    Oh, you went to the Philippines!
    Proud filipino here

  44. Dale Clark says:

    To get to the 7.2 billion people, none of the 44 friends could be friends of any of the 44 friends of any of the other 44 friend connections. Damn! I'm a math whiz!

  45. Oliver Gomez says:

    What were you doing there in Manila? Were you in vacation?😁👌🤘

  46. Howard Petterson says:

    What amazes me is how you can speak so coherently on the street with such complex subject. How many takes and did you use teleprompter.
    I did the 6°test and it worked

  47. Larry Lund says:

    Friends help you move, good friends help you move bodies. Hence the difference of separation. Yet, via networking 6 degrees or 1/60th of a full circle, there are a huge number of friends of friends who will agree to help you move bodies. This is the Clinton crime network. Also, this is why the blackberry and computer files are so important to have been recovered. Yes, all the information has been recovered. If you have 6 friends how many of them are sweating bullets?

  48. David Ryder says:

    Of course you're more likely to get a job through random acquaintances rather than your friends. Your friends KNOW what a screw-up you are…

  49. B B says:

    So yes it is 4 degrees of separation. I cheated I am a professional chauffeur.

  50. jolllyroger1 says:

    Long winded bunch of bs with zero science

  51. Emma_cappie says:

    Is 1 degree of separation someone you already know?

  52. Evan Jones says:

    Socal media brings down the 6 points as you have more groups of people who each pull on even more people, for example if you have a group of real friends and a group of friends on social media, they are two seperate groups but act as one group when pulled

  53. Fazal828 says:

    Wait what's your email how would I email you dummy

  54. bandie9101 says:

    1:00 – the story really tells us: sanitize user input!

  55. Irfan Ali says:

    There is no connection with 6 degree to 46. 360÷46=

  56. Irfan Ali says:


  57. mjgarrett9885ify says:

    I had this same idea . But it was for a movie and extorting every nation on earth . I had this movie idea when computers just began .

  58. mjgarrett9885ify says:

    P.s. Those 6 people also pick 6 people they know and so on and so forth . So by picking 6 people and those 6 people also pick 6 people and those 6 people would also pick 6 people and this would connect you to everyone

  59. Wesley Barley says:

    I would love to get a follow up to this video. How did it go? Did you get any emails?

  60. Alessandro Tagliafierro says:

    Came for the video, stayed for Neil

  61. Nunya _ says:

    I'm 44 degrees separated. :{

  62. KootFloris says:

    Facebook calculated once my number of separation, it was 3,2 that was even lower than Marc Zuckerberg. That is most likely because I know some people below 3,0.

  63. Scientist Albert Einstein says:

    2:13 LOL anyone noticed how the yanks spread their doctrine of the American country separation by calling it North America and Latin America? So funny how they think America is USA, they even paint in red what they call "Latin America" hahahahahaahahahaha so funny how they are trying to spread misinformation. Why don't they call USA "Euro America"? because they have an agenda, what is that agenda? I don't know but there is something behind it if they are trying to spread misinformation as simple as that.

  64. modmou4690 says:

    It's funny you said Manila I have an uncle that lives in the Philippines

  65. Russ says:

    WTF is myspace?

  66. Rodney Dempsey says:

    My mates uncle's aunty's stepson owns the Father of the daughter who gave birth to the Queens Corgi .

  67. Nick a says:

    That's terrifying, an assassin could find me in 4-6 steps Paranoia intensifies

  68. Christian Yamil Perez says:

    Very interesting but you lost me aafter five minutes.

  69. Libellule says:

    In Norway we have a tv show where famous norwegian people are dropped off some random place in the world and try to find another famous person through 6 people

  70. J C says:

    Dammit. You should've said "this is the origin of 6 degrees of Kevin Bacon." 🤣

    Anybody who was around when the internet started knows that's how it works 😂

  71. Sophie Wade says:

    Dam sam

  72. Scrimjaw says:

    Makes me glad I'm not on faceache, oops facebook.

  73. sparrow hawk says:

    Let's take the population of the U.S. Navy and one sailor. This one sailor spent 22 years (1964 – 1986) in the USN and, without any knowledge of this theory, asked himself one day, how is it that I have never known any other sailor who had any direct knowledge (1st hand) of the "Gulf of Tonkin Incident" or knew any other sailor who had direct knowledge (2nd hand)? Perhaps the incident that started the Vietnam War DID NOT OCCURR as reported. This is a true story, I am the original sailor and I had a Top Secret SCI Clearance. Are 58+ thousand Americans dead based on a lie by the Democrat President Lyndon Johnson? Someone who is good at math please let me know, or if you were a crew member on the USS Maddox or USS Turner Joy.

  74. Arctic badger says:

    So it’s similar to pyramid scammers 🥴🥴🥴


  75. Ga Tech Company says:

    "Or did it?"
    Vsauce music plays.

  76. Ricardo González says:

    Great video!

  77. Marianne Plantinos says:

    Can’t believe he was at manila

  78. JackelLight says:

    On snap chat with the mentions and maps I some how got someone across the world

  79. Kyle Adler says:

    Is there a program that exists where you input your own social media profile with another one to find the six degrees of separation? Would be pretty fun to play around with.

  80. ferkemall says:

    She will start with the headache 2/ im not in the mood 3/ i want my own space 4/i want separate beds 5/ oh if you must 6/ the divorce ! /UK

  81. ninjxxitty says:

    i dont really understand how youre suppose to get a package to someone in that way. it sounds really confusing

  82. Jake Livni says:

    Years ago I realized that I'm connected to Albert Einstein by (considerably) fewer than six degrees of separation. Also to Bekenstein, Hawking, Feynman, Thorne and a bunch of others. Never met them, though. And hence other people I know are connected to these famous physicists by just one more degree of separation (at most, possibly even less). Quite remarkable.

  83. Mao man says:

    The woman in purple at 1:56 made me giggle

  84. manthan Patil says:

    Bro none of my friend wathch your channel they only play pubji and those you arebscience enthusiase like me dont use to watch youtube

  85. jeff flack says:

    Hey! I'm Mr.Jeff, ;Thanks For The Terrific Video/Presentation of "6 DEGREES"! I Don't Have "44 Friends "Per Se", However, Thanks To My MANY "Facebook Friends", I Have A Link To Several People, NOT, In My Routine, Or Circle Of Everyday Life! Lol!

  86. vini_n _come_doce says:

    That's the weirdest theory on the planet

  87. Hesham Sugail says:

    Hit a like if you firstly know about this concept from House of Cards.

  88. David Lecompte says:

    2019 and there is now more than 7.26 billion people on earth.

  89. Ojas Dighe says:

    "I know a guy who knows a guy".

  90. fmmf2010 says:

    hi, i live in spain, and dinner in a restaurant where the owner meet "mayden days" artist that work with "tim burton"

  91. Lil Shadow says:

    Lives on earth

  92. Beray says:

    I know the video is old but wouldn't the experiment work better if instead of sending it out to 1 person you think has the best chance to get to you but to send it to everyone you know on a first name bases with the number 1 in the email with instructions to pass it on to everyone they know on the first name bases by increasing the number by 1 unless they know you personally then they would simply only send it to you.

    Part of the problem with the experiment of sending it to someone you think has the best chance, is that you may know others who have a better chance but that you make errors in your assumption of better choices.

  93. Peter Flack says:

    What if you are a psychic medium and you have 0 friends, and its 6 to 4 forcible connection(s)?

  94. Peter Flack says:

    Meaning you have 1056 stalkers from the afterlife who are strangers and they are half in your door and half outside?

  95. M M says:

    But people who I know have the same friends of me 🤦😂

  96. M M says:

    Are people thesedays play chess like that?

  97. cilstr says:

    YAY! MELBOURNE!! (love it when you are in melbs 😉 )

  98. Keith Heiskell says:

    So how long would it take for everybody to know each other

  99. Fritz Guye says:

    There are now 7.6 billion. Does that mean there are now 7 degrees of separation?

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