Two MIT professors and a third from Harvard University described their research at a January 13 syposium, part of a regional meeting held at MIT by the National Academy of Sciences.
Catherine Dulac, assistant investigator for the Howard Hughes Medical Institute (HHMI) and professor in the Department of Molecular and Cellular Biology at Harvard, spoke about her work on how mammals detect pheromones -- species-specific chemical signals that cause a host of reproductive and social changes in both males and females. She is exploring how the mammalian brain manages to discriminate among the 100,000 molecules it is capable of identifying through olfactory neurons in receptors.
Mammals have two distinct ways of detecting odorants and pheromones: through the main olfactory system and the vomeronasal organ or VNO. The VNO is a specialized part of the olfactory system located within the nasal septum. Its chemosensitive cells project via the vomeronasal nerve to the accessory olfactory bulb. While the structure has been thought to be absent in higher primate adults, there is some debate over whether humans have a vomeronasal organ, Dr. Dulac said.
Wolfgang Ketterle, professor of physics at MIT, spoke about his work on a new form of matter, the Bose-Einstein condensate. These condensates form when atomic particles are slowed to a crawl. At never-before-achieved temperatures, atoms move in concert and form one giant "matter wave" instead of bouncing around like billiard balls or in "wave packets."
At nano-Kelvin temperatures, the Bose condensate is a gas more than a million times more dilute than air. Under those conditions, Professor Ketterle found that he could see quantum mechanics in action.
"This is a direct observation of the wave nature of atoms," he said. "We have a system where we can virtually see wave functions with the naked eye." The potential uses range from precision instruments like atomic clocks to an atom laser -- a device that generates intense, coherent atomic beams.
A Bose-Einstein condensate is one of the few macroscopic quantum phenomena -- others include superconductivity and superfluidity -- where quantum mechanics reveals itself on a macroscopic scale.
Steven Pinker, professor of psychology at MIT and director of the Center for Cognitive Neuroscience, spoke about the rules that govern human languages. He said his lifelong goal has been to figure out how the series of "hisses, hums, squeaks and pops" made by human beings get translated by the brain into information.
There are words that we memorize -- and people must learn an average of one every 90 minutes of their waking lives starting at age 1 to develop a typical vocabulary by high school -- and there is our ability to predict an ending for a verb even if it's a word you've never heard before. This is a distinct mental mechanism, Pinker says, one of the tools that allow us to make "infinite use of a finite system" to communicate.
The public symposium was organized by Sylvia T. Ceyer, the J.C. Sheehan Professor of Chemistry at MIT, and Don C. Wiley of Harvard's Department of Molecular and Cellular Biology and an investigator at the HHMI.
NAS, chartered by Congress in 1863 to advise the federal government on scientific and technical matters, is made up of science and engineering researchers dedicated to furthering the use of science and technology for the general welfare.
A version of this article appeared in MIT Tech Talk on January 27, 1999.
