LOS ANGELES-Humans process a lot of information through their ears. Males of the species tend to consider a lot of this information to be superfluous. Apparently, so does Mother Nature.
In an evolutionary development that crosses all racial lines, emerging populations of human males now possess a fourth bone in their middle ears.
The new bone, which is a tiny, straight sliver, blocks the hammer from striking the anvil and pushes the anvil away from the stirrup, breaking the chain of vibration that sends signals to the brain that are interpreted as sound.
The bone's shape and position in the chain have made it easy for physiologists to give it a name: the chisel.
The new bone is the first ever discovered that is held in place by smooth muscle, bringing it under autonomic nervous system control.
In times of danger, excitement, or attentiveness, the sympathetic nervous system controls the position of the bone, moving it out of the way so the ear functions normally.
In moments of tedium, such as nagging or lectures on the Kreb's citric acid cycle, the parasympathetic nervous system takes over, moving the chisel between the hammer and anvil and turning off all sensations of sound.
"It's the most exciting discovery of my lifetime," declared S.A. Watt, the UCLA physiology professor who heads the team of scientists and physicians credited with the discovery.
"Sure wish I had one," he added.
When asked why there are no known cases of the extra bone in girls or women, Watt noted, "I can only speculate. Silence would seem more likely to evolve as an adaptive function in men. Silence tends to bore women, but it often relieves boredom in men.
"An anatomical change that creates greater harmony between the male brain and the environment makes perfect sense from an evolutionary standpoint.
"But if that same change creates discord between the female brain and its environment, it would be maladaptive and counter to everything we've come to understand about evolution.
"Assuming that the chisel is a sex-linked trait, it has likely come about as a result of mutations in the Y chromosome. If it were in the X chromosome, it would almost certainly be appearing in females, although probably in smaller numbers as a recessive trait."
Grant money to investigate the feasibility of chisel transplants from organ donors is proving extremely easy to obtain, according to Dr. Watt.
Religious leaders are denying that evolution is the cause for the new bone.
"God's putting it there to compensate men for the rib He took to make Eve," stated Reverend Gary Marlowe.
"It's a wonderful gift. I wish I had one, too," Marlowe sighed. "My wife and I are expecting a son in a few weeks, and I am praying night and day that he will be blessed with a chisel."