STRANGE BUT TRUE: Humans are a bonded species, living amid family and friends in social networks

Q.  If you start with YOU as a single person, or a 1, then raise this number to 5 people, 15, 50, 150, 500 and 1500, what’s happening here communally?

A.  These are the groupings in a typical person’s life, beginning with 5 intimates, 15 best friends, 50 good friends, 150 friends, 500 acquaintances and finally 1500 people that he or she can recognize, says evolutionary anthropologist Robin Dunbar in “New Scientist” magazine.

We humans are a bonded species, living amid family and friends in social networks that have dramatic effects on our lives, influencing how we eat, what we wear, even how we laugh.

Based on the group size of other social primates and on human brain size, we could expect our own group to swell to about 150, or about the limit “where we can still have a real relationship involving trust and obligation.”

The 150 figure, called “Dunbar’s number,” is surprisingly common in human social organizations:

“Historically, it was the average size of English villages.

It is also the ideal size for church parishes and is the size of the basic military unit, the company,” Dunbar explains.  Contrary to the urban myth that many people have 1000 or more friends on Facebook, the typical user actually has 120-130 friends--about the same as offline.  “Of course, anyone can sign up 500 or even 5000 friends online, but how many of these are real friends who would help out if the person were in a fix?”

Q.  How many colors can the average person see?

A.  Most of us are “trichromats” with three different types of cones, each able to distinguish roughly 100 shades of color, for a total response of 100 x 100 x 100 = roughly 1 million different colors, says Veronique Greenwood in “Discover” magazine.

Taking one cone away results in a “dichromat,” with the number of possible color combinations dropping by a factor of 100, down to 10,000.

Yet living among us are believed to be “tetrachromats” with a fourth cone, letting them see 100 times more colors, or 100 million--some shades so subtle they have no names.

“And because perceiving colors is a personal experience, they would have no way of knowing they see far beyond what we consider the limits of human vision.”

In fact, some observers believe that the natural world may lack sufficient color varieties for the brain to learn to use a fourth cone.


Q.  What’s it take to create a 40-foot-high flaming “kaboom” that used to be a car--a la Hollywood?

A.  Plenty of art and science as well as mortars, says Shane Snow in “Wired” magazine.  Cinematically, even a small fender-bender can trigger an inferno, whereas in reality cars don’t usually explode, even if driven off a cliff or the gas tank gets hit by a volley of bullets.

“It takes at least 200-man-hours to prep for something that lasts four seconds onscreen,” special effects expert Drew Jiritano told the magazine.

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