Long Hair

Maybe they are not particularly interested in the superficial trivia which is 'fashion'?
I expect when they go bald they don't worry about that either.
Del

They have a haircut less often.

So that superficial people (Specially apposite gender) don't fall in love with them,which may be the cause of distraction of their attention.

extra brain cells leaking out That where they store it

Most??

Even his hair is not long.

You might want to peruse this site:

Luxuriant Flowing Hair Club for Scientists™
Luxuriant Former Hair Club for Scientists™
Luxuriant Facial Hair Club for Scientists™

It is the sign of determination, a term called VAIRAGYA in Sanskrit. A pending job or a research quest for a solution, which is incomplete in its accomplishment, a sign of self reminder that you got some pending job to solve. The daily look at the mirror is a self reminder. those who see one with a long hair or beard also may happened to ask the reason, which again is an external reminder.

Even yogies are in the practice of not going for a hair cut and just wait till the mission to complete.

To my best of knowledge, it is the sign of concern and an exhibition of a serious engagement for a cause on hand.

Indeed. Additionally, I think in European tales of yore, chivalrous knights on a quest cut not their flowing locks 'till the quest was complete.

And what about Samson...?

Often they are in their labs 18+ hours a day seven days a week, some days they even sleep there...

There is no barber/hairdresser willing to work at 3 am!!

Could this be restated as

Why do most human beings in the world have short hair, compared to scientists?

I notice that most women also have long hair. Is there some connection?

This one has a simple answer: there's no dress code in the academic world.

Therefore the scientist need not clip, shave, bouff or otherwise conform to the grooming norms of the culture at large.

Forget about that category

The reason people grow their hair (If subconsciously) is that hair is like a malleable fingerprint, never the same. When short all look the same. Long hair is a profound statement of ones personality, if on cares to display it and one still has it.

The longest hair I had was when I was inventing the hoover attachment which can cut hair in any style fashion or color, fast.

The 6000rpm cutting tools never worked to satisfaction on our pets so I never subscribed to volunteering and gave up in the end. Five years is a long time for hair to grow.

Then I saw Meg at Hairport and still have the ponytail, or the Heidschnucke has it stashed away somewhere.

Nowadays I couldn't care less and find myself looking like Sid Viscous at times. Nobody cares about superfluous things much around here anyway.

Have one on me, Ky.

Because there are literally 1,001 things that can go wrong when carrying out scientific research.

Ever tried tearing your hair out in frustration when you're as completely bald as Vin Diesel?

musicians. hippies. kids, ect. are aways trying to differrenticate themselves from main steam society. 'del the cat' has a good point too. a hair cut could be low on there list of priorities or they might not even think about it.

Having had long hair for over 45 years there's only one time I regretted it. A gas burner blow back reduced it to a frazzled mess, (didn't do the beard much good either). All grown back now

That's an easy one. There isn't enough room in their heads to contain the brain cells. The long hair serves as storage for the excess.

The reasons are different, I think. Another interesting fact I've mentioned is that a lot of female scientists have short hairstyles. Barbara McClintock, Rachel Carson, Vera Rubin, and many others. And all of them have curly hair! Already found some best hot rollers for changing my hairstyle. Hedy Lamarr was so cute with her curly locks