Let Them Halve Cake
Reported March 2007
NEW YORK (Ivanhoe Broadcast News) -- How do you divide a piece of birthday cake so both kids are happy with what they get? Wise men and women have been trying to answer that question since the time of King Solomon, and it's a problem every parent is familiar with.
"I will ask the girls, 'Which one of you would like to cut, and which would like to choose?'" says mother Rachel Fishman Green.
The method is called divide and choose. Works fine for a plain vanilla cake. The cutter slices it right down the center. Chooser gets one half; cutter the other -- all is fair. But what if the dispute is over something more complex, like a country or the house and kids in a divorce? You can't just slice them down the middle.
How do we divide these things? It's all about fairness.
"I think fairness is one of the most important, if not the most important, problem in the world today," Steven Brams, Ph.D., a mathematical political scientist at New York University, tells Ivanhoe.
Dr. Brams carved out a new mathematical formula, called the Surplus Procedure, that promises to make settling disputes a little easier. It works by numerically taking into account the values people place on the different aspects of what's in dispute. Each party first gets at least 50 percent of what they want most. What's left over is then divided proportionally, so both parties get half of what they wanted and then some!
"More than a fair share," Dr. Brams says. "They couldn't have done better. There's no allocation that gives them both more."
He says you may one day be able to solve disputes by downloading the Surplus Procedure right from the Internet. And it's also strategy-proof. A person cannot game the system to get more than their fair share. And that's great news for moms.
Click here to Go Inside This Science or contact:
Steven Brams, Ph.D.
New York University
American Mathematical Society
Providence, RI 02904-2294
The Mathematical Association of America
Washington, DC 20036-1358
El Niņo's Wicked Weather
This Month's TV Reports
El Niņo has popped up again this winter, but spotting him and predicting what he'll do are two different things.
Using this new nail on your home today may save you when nature comes knocking this hurricane season.
Small Fish Detect Big Problems
A new way to monitor toxins in our nation's water supplies -- tiny bluegills.
Sea Urchins Reveal Mysteries of Cancer, Alzheimer's & Infertility
The mysteries of the sea urchin may help solve some of medicine's most difficult and deadly problems.
Listen To Your Heart
A new improvement to the old stethoscope has doctors detecting deadly heart murmurs with just one visit.
Headed on vacation and not sure which book you want to catch up on? Don't worry; travel light with hundreds of best sellers and your single leather-bound book using "E Ink" pages.
They're creepy and crawly, but not all beetles are bad. The Namib Desert beetle is showing humans how to harvest water and even fight germs.
In just a matter of weeks, this one-of-a-kind drug may help heal 14 million Americans with the redness and bumps of rosacea.
Let Them Halve Cake
Two people are fighting over the same thing. How do they divvy it up fairly so both are happy? A new formula makes settling disputes easier.
Better Macular Degeneration Diagnoses
A new, high-tech test is changing the way eye doctors diagnose wet age-related macular degeneration.
Hispanics make up 14 percent of Americans. As that number grows, so will the need for Spanish-speaking health care workers. See how one program is breaking down language barriers and paving the way for better care.
Pinpointing Problems in the Brain
A powerful new brain scanning device gives new hope for patients with dementia, epilepsy, migraines, Parkinson's disease, depression and traumatic brain injuries.