do I amuse you?

If you wonder why some guys are funny, and other guys not so much: blame testosterone.

For the doc­tor, Sam Shus­ter of New­cas­tle Un­ivers­ity, U.K., uni­cy­cling be­gan as a hob­by. But it be­came a study of hu­man na­ture as he wheeled about lo­cal streets and no­ticed the mul­ti­tudes of jokes he sparked—of­ten lame and pre­dict­a­ble, he said, and usu­ally from men. Guess­ing this might re­flect a bi­o­log­i­cal phe­nom­e­non, he pro­ceeded in a year-long in­ves­ti­ga­t­ion to doc­u­ment over 400 peo­ple’s re­ac­tions to his one-wheeled jaunts.

Over 90 per­cent re­sponded phys­ic­ally, he found, such as with ex­ag­ger­at­ed stares or waves. Al­most half re­sponded ver­bal­ly—more men than wom­en. He­re, said Shus­ter, sex dif­fer­ences emerged in force: 95 per­cent of adult wom­en praised, en­cour­aged or showed con­cern, while men in­stead un­leashed of­ten-snide jokes 75 per­cent of the time. Equally strik­ing, he said, was the jokes’ re­pet­i­tive­ness. Two thirds re­ferred to the num­ber of wheels, such as “lost your wheel?”

One of the most con­spic­u­ous find­ings, to Shus­ter, was the way the male re­sponse changed with age.

It started with cu­ri­os­ity in child­hood, years 5 through 12—the same re­ac­tion as young girls. But around the ages of 11 to 13, boys’ re­sponses de­gen­er­ated in­to phys­ical and ver­bal ag­gres­sion, Shus­ter found; these scamps in fact of­ten tried to get him to fall. Re­sponses be­came more ver­bal dur­ing the lat­er teens, turn­ing in­to mock­ing jests or songs, Shus­ter re­ported. This lat­er evolved in­to adult male hu­mor, char­ac­ter­ized by put-downs that Shus­ter as­cribed to la­tent ag­gres­sion. Par­tic­u­larly pug­na­cious re­marks, he said, came from young male mo­torists at the ages of peak viril­ity.

But the com­bat­ive­ness waned as life wore on, Shus­ter found: old­er men gave more neu­tral or friendly re­marks.

Anyone who watched Goodfellas or The Sopranos for more than an hour would soon figure out that much male humor, if not more, isn't just gut-busting, but (to put it bluntly) ball-breaking.