:: By Lydialyle Gibson

:: Graphic by Allen Carroll

Investigations ::

Don’t be shy

In Martha McClintock’s laboratory, fortune follows the brave. Researching the health hazards of timidity, McClintock, director of the University’s Institute for Mind and Biology, compared female rats’ willingness to explore new territory with their chances of developing and dying from cancer.

The boldest among the study’s 81 rats, some of them sisters and all of them genetically prone to tumors, averaged an 850-day lifespan, versus 573 days for their shy lab mates. Shy females developed mammary and pituitary tumors earlier and died approximately six months sooner than adventuresome females.

Reporting its findings in the October Hormones and Behavior, McClintock’s research team hypothesized that rats’ reproductive cycle may affect cancer development: by 15 months, most shy rats had entered the final, low-estrogen stages of reproductive expiration, while nearly 60 percent of uninhibited rats still experienced regular or constant periods of heat, or estrus.