There is an apocryphal story about a graduate mathematics student at the University of Virginia studying the properties of certain mathematical objects. In his fifth year some killjoy bastard elsewhere published a paper proving that there are no such mathematical objects. He dropped out of the program, and I never did hear where he is today. He's probably making my cappuccino right now.

There is an apocryphal story about a graduate mathematics student at the University of Virginia studying the properties of certain mathematical objects. In his fifth year some killjoy bastard elsewhere published a paper proving that there are no such mathematical objects. He dropped out of the program, and I never did hear where he is today. He's probably making my cappuccino right now.

This week, a professor named Peter Sheridan Dodds published a new paper in Physical Review Letters further fleshing out a theory concerning why a 2/3 power law may apply for metabolic rate. The 2/3 law says that metabolic rate in animals rises as the 2/3 power of body mass.  It was in a 2001 Journal of Theoretical Biology paper that he first argued that perhaps a 2/3 law applies, and that paper -- along with others such as the one that just appeared -- is what has put him in the Killjoy Hall of Fame.  The University of Virginia's killjoy was a mere amateur.

The 2/3 scaling law, you see, is intuitively obvious (even if not intuitively obvious to truly defend in detail). The surface area of animals scales as the 2/3 power of their body mass, and so the rate of heat loss scales as the 2/3 power. If metabolic rate scaled as the 2/3 power, few theorists would probably have bothered taking the problem on.

But in the 1930s one Max Kleiber accumulated data that suggested to him that metabolic rate scales as the 3/4 power of body mass. It came to be known as Kleiber's Law. 3/4 is fun. ...to a theorist. 2/3, however, is boring. 3/4 is so fun that theorists had a field day trying to explain it, and there was an especially gigantic spike in the fun starting from 1997, especially from a series of papers by West, Brown and Enquist, and also by Banavar and Maritan.

And that's when buzzkill Dodds came along with his 2001 paper. He re-examined the data, and suggested that a 2/3 law could not be rejected. There may be no 3/4 law to explain after all. Nothing to see here, move along everyone. That paper further put salt in the wound by pointing out that one of the theories deriving the 3/4 law had an error.  

Although Dodds is still at it with his current paper, to compensate for his party-downer laurels, he's accumulated some of the most interesting research out there, from rivers to bodies to disease to the happiness of songs over time. (Thanks, Peter, for being a good sport.)

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Mark Changizi

Mark Changizi is Director of Human Cognition at 2AI, and the author of The Vision Revolution (Benbella 2009) and Harnessed: How Language and Music Mimicked Nature and Transformed Ape to Man (Benbella 2011). He has expertise in theoretical neurobiology, vision, cognitive science, and language. Born in 1969 and raised in Fairfax, Virginia, he attended the Thomas Jefferson High School for Science and Technology, and then went on to the University of Virginia for a degree in physics and mathematics, and to the University of Maryland for a PhD in math. In 2002 he won a prestigious Sloan-Swartz… Read more