Vol. 38, No. 18

1-18-2006
By: Research Communications staff

Discoveries briefs 1/19/06

Years of loud noise may lead to tumor
New research suggests that years of repeated exposure to loud noise can increase the risk of developing a noncancerous tumor that could cause hearing loss.

"It doesn't matter if the noise comes from years of on-the-job exposure or from a source that isn't job-related," said Colin Edwards, a doctoral student in the School of Public Health.

In the current study, people who were repeatedly exposed to loud noise over the span of several years were on average one-and-a-half times as likely to develop this type of tumor compared to people who weren't exposed to such noise on a regular basis.

The tumor, called an acoustic neuroma, grows slowly and symptoms typically become noticeable at around age 50 or older. Of the 146 people with such a tumor in this study, nearly two out of three were 50 or older. An acoustic neuroma slowly presses the cranial nerve that is responsible for sensing sound and helping with balance. Symptoms include hearing loss and tinnitis, or a constant ringing in the ears. Judith Schwartzbaum, an associate professor of epidemiology in the School of Public Health, was one of the co-authors of the study.

www.osu.edu/researchnews/archive/tooloud.htm

Research reveals why some stocks keep winning, while others keep losing
A new study suggests that investor psychology plays a big role in why stock prices show strong momentum - the tendency for prices to continue in the same direction, either rising or falling.

While stock analysts and researchers have long known about stock momentum, there has been debate about what causes it, said Bing Han, co-author of the study and assistant professor of finance. "We found that it is a type of psychological bias on the part of many investors that seems to drive momentum," Han said. "Investors tend to hold on to their losing stocks too long and sell their winners too quickly. This triggers momentum."

The tendency to hold on to losing stocks and sell winners is called the disposition effect, Han said. If many investors fall prey to this type of bias, it will affect stock momentum. What happens is that the stock price for a company may go down because of some bad news about that company. But many investors don't want to sell their stock at a loss, so they hold on, hoping the price will rise later. If too many people hold on to their stocks, that means the stock price does not accurately reflect the bad news about the company. This prompts some investors, noting that the stock is overvalued, to "short sell" the stock, betting that prices will fall. This cycle continues to push prices of the stock down, creating a momentum effect.

A similar situation occurs when a stock is rising because of good news for a company.

www.osu.edu/researchnews/archive/stockmom.htm

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