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Updated 11:30 AM December 6, 2004




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Research Notes

Online, social loafers become productive when given a challenge

New research shows that people in online groups contribute more when issued a challenge and when they believe their efforts provide a unique benefit.

Results could be used to design online communities that encourage increased participation. Hundreds of thousands of online communities exist for people to share news and information on issues and interests they have in common.
Researchers found that if you emphasize how unique people’s contributions are, they were willing to contribute more to online communities.

Researchers from U-M and collaborators from Carnegie Mellon, University of Minnesota and University of Pittsburgh studied the problem of under-contribution to the communities by examining factors that motivated people to contribute to an online movie rating service called

The paper, "Using Social Psychology to Motivate Contributions to Online Communities," appeared in the proceedings of the Association for Computing Machinery Conference on Computer Supported Cooperative last month.

Like most online communities, a handful of MovieLens members do much of the work. The site had 80,000 registered users with about 7,000 active in the six months prior to the research.

Besides providing insight into ways to motivate behavior online, other findings from the study contradict conventional wisdom about social loafing, a term used to describe the tendency for people to exert less effort in a group task than in a comparable individual task, says co-author Paul Resnick, professor in the School of Information.

"We found that if you emphasize how unique their contributions are, they were willing to contribute more," Resnick says. "Even in something so mundane as the uniqueness of what kind of movies you rate, that was enough motivation for them to rate more."

The ability to apply the social science findings to online communities has many implications for the communities in existence, Resnick says, many of which fail because of under-contribution.

One in six older adults with chronic ailments skip Rx

A recent survey of older adults finds that 18 percent of those with chronic conditions such as heart disease and depression skip some of their prescription medicines because of out-of-pocket cost pressures, and 14 percent do so at least every month.

Based on the study's findings, the authors estimate that every month, this cost-related medication skimping leads more than a million Americans with diabetes to use less medication for that illness than was prescribed to them, and causes more than 1.6 million people with asthma to miss some of their doses of medication.

The findings, from a nationally representative survey of 4,055 adults older than 50, were published in the October issue of the American Journal of Public Health by a team from the U-M Health System, the Veterans Affairs Ann Arbor Healthcare System and Stanford University. The study was funded by the VA.

The study finds that seniors whose out-of-pocket prescription costs are more than $100 a month, and those with low incomes or no prescription drug coverage, are at the greatest risk for skimping on their medications.

Other results of the survey indicate that people with chronic illnesses were more likely to cut back on certain kinds of medications over others, suggesting that patients are selective about which drugs they go without.

"We found that many patients go without drugs that relieve serious symptomatic conditions such as back pain or ulcers, while others skipped drugs that are life-sustaining, such as blood pressure and cholesterol drugs, but that might not cause any noticeable difference in day-to-day functioning," says lead author John D. Piette, a VA career scientist and associate professor of internal medicine at the Medical School.

More patients regularly cut back on costs by forgoing their medicines for depression, asthma, ulcers, arthritis, migraines and back pain, for example, than went without medicines for high blood pressure, high cholesterol or diabetes.

In addition to Piette, the study's authors include Dr. Michele Heisler, also of the VA Ann Arbor Healthcare System and the Medical School, and Todd H. Wagner of the VA Health Economics Resource Center and Stanford University.

Hello, hello, Earth?

If ET ever phones home, chances are Earthlings won't recognize the call as anything other than random noise or a star.

New research shows that highly efficient electromagnetic transmissions from our neighbors in space would resemble thermal radiation emitted by stars.

U-M physicist Mark Newman, along with two other researchers, have extended the pioneering 1940s research of Claude Shannon to electromagnetic transmissions in a paper published last month in the American Journal of Physics, called "The Physical Limits of Communication, or Why any sufficiently advanced technology is indistinguishable from noise."

Shannon showed that a message transmitted with optimal efficiency is indistinguishable from random noise to a receiver unfamiliar with the language in the message. For example, an e-mail message whose first few letters are AAAAA contains little information because the reader can guess what probably comes next—another A. The message is totally non-random. On the other hand, a message beginning with a sequence of letters like RPLUOFQX contains a lot of information because one cannot guess the next letter easily.

Paradoxically, however, the same message could be just a random jumble of letters containing no information at all; without knowing the code used for the message, one can't tell the difference between an information-rich message and a random jumble of letters.

Newman and his collaborators have shown that a similar result holds true for radio waves. When electromagnetic waves are used as the transmission medium, the most information efficient format for a message is indistinguishable from ordinary thermal radiation—the same kind of radio waves that are emitted by hot bodies like stars. In other words, an efficiently coded radio message coming from outer space would look no different from a normal star in the sky.

Say a human tries to tune into extraterrestrial life. "What if (the aliens) have gotten it down? With a few hundred years practice at doing this, you'd have discovered the most efficient way to encode your radio messages," Newman says. "If (people) did pick up a signal from little green men, it would probably look like a star to them and they would just pass over it and move on to the next thing."

Women wait longer for emergency heart treatment

In a heart attack, the saying goes, "Time is muscle." The faster a person gets treated, the better his or her chances of survival and recovery.

But a study finds that women who have heart attacks wait longer than men to receive an emergency procedure that can re-open clogged blood vessels and restore blood flow to the heart muscle. The study also finds that the longer any patient waits for this treatment, the higher his or her chances are of dying before leaving the hospital.

The procedure, called emergency angioplasty or percutaneous coronary intervention, has the biggest impact if it is performed within 90 minutes of a patient's arrival at the emergency room door.

The study shows women on average waited more than 118 minutes before treatment began, compared with 105 minutes for men. Add to that the 20 extra minutes it took for the average woman to reach the emergency room after her symptoms began, compared with men, and the result is half an hour more of wasted time and damaged heart muscle.

The results were presented at the annual Scientific Sessions of the American Heart Association by Dr. Mauro Moscucci, who directs interventional cardiology at the Cardiovascular Center. He presented the data on behalf of the Blue Cross Blue Shield of Michigan Cardiovascular Consortium, a joint research effort designed to study and improve angioplasty care, which is funded by the Blue Cross Blue Shield of Michigan Foundation.

Other authors from U-M were Dean E. Smith, Sandeep Jani and Cecelia Montoye.

Easily influenced consumers play it safe when making purchases

Consumers who are greatly influenced by the opinions of others tend to be cautious when deciding what products to buy, says a U-M business professor.

New research by marketing professors David Wooten of the Stephen M. Ross School of Business and Americus Reed of the Wharton School shows that influenceable buyers do not seek to enhance their self-image by being flashy trendsetters. Instead, they try to protect themselves against social disapproval by avoiding choices that may make them look bad or attract unwanted attention.

"Contrary to popular perceptions, easily influenced consumers are more concerned about looking bad than looking good," says Wooten, whose findings appear in this month's issue of the Journal of Consumer Research. "For these individuals, conformity is a protective strategy that enables them to avoid undesired, contestable or even noticeable impressions."

To determine how individual differences affect the perception and purchase of brands and products, Wooten and Reed conducted two studies focusing on consumers' susceptibility to normative influence (SNI).

They define SNI as the need to identify with others or to enhance one's image with products and brands, or the willingness to conform to others' expectations regarding purchase decisions. Individuals with high SNI have a desire to fit in and gain social acceptance, while those with a low SNI are less concerned with others' perceptions of them and do not feel as pressured to conform.

In their first study, the researchers asked participants to evaluate advertising claims associated with two product categories—mouthwash and soap. They found that high-SNI (influenceable) participants responded more strongly than low-SNI (not easily influenced) participants to protective messages emphasizing the avoidance of undesirable outcomes, such as bad breath and body odor, which are noticeable to others.

Wooten and Reed conducted a second study to examine how SNI influences individual tendencies to avoid impressions that may be contested or noticed. They found that as people become more easily influenced, they are less likely to present themselves in ways that would be challenged by others.

Heart patients helped by implanted defibrillators

Implanted devices that can shock a failing heart back into regular rhythm do an excellent job of keeping patients alive, two U-M studies find.

The research also suggests that doctors may be able to categorize their patients according to their individual risk factors, to determine who might get the largest benefit from the expensive devices, called implanted cardiac defibrillators (ICDs). The studies reinforce the importance of providing good follow-up care to all heart failure patients, whether or not they receive an implanted device.

With Medicare poised to start covering ICDs for many more patients than ever before, the study results come just in time to help doctors decide which patients might get the greatest benefit from the costly devices. More than half a million more people may qualify for ICDs, which cost around $20,000, under Medicare guidelines that will take effect soon.

The data were presented in two talks at the Scientific Sessions of the American Heart Association by a Cardiovascular Center team. The researchers found that among patients with congestive heart failure and a heart rhythm irregularity called ventricular arrhythmia, those who received an ICD were 60 percent less likely to die in the next year, and 48 percent less likely to die in three years, than those who did not receive an ICD. Most of this reduction in death risk was due to reduction in heart-related deaths. ICDs are specifically designed to prevent sudden cardiac death, in which the heart's electrical system goes haywire, causing it to stop beating.

But ICD recipients who had co-existing medical conditions, especially diabetes or kidney failure, were much more likely to die within a year of getting the device than other patients. So were patients who received an ICD but didn't get heart-protecting medications that are part of standard heart-failure therapy.

The lead researcher was cardiology fellow Dr. Paul Chan. His mentor, internal medicine professor and VA Ann Arbor Healthcare System researcher Dr. Rodney Hayward, also was on the research team, as were data analyst Jenny Davis and Dr. Mark Starling, who directs the Ann Arbor VA cardiology division.

Household stocks: The fewer, the better

Who says a diverse portfolio is better? When it comes to individual investing, stock trades made by households with fewer stocks outperform those with more diversified accounts, according to researchers at U-M and the University of Illinois.

Moreover, the excess return of these concentrated portfolios is stronger for local stocks and for stocks not included in the S&P 500 Index.

"On average, the stocks bought by individual investors under perform the stocks they sell by a wide margin," says Clemens Sialm, assistant professor of finance at the Stephen M. Ross School of Business. "However, the reverse is true for wealthy households with concentrated investments.
Stock picks of concentrated investors (those holding one or two stocks) outperform those of diversified investors (those with three or more stocks) by about one percentage point over the year following a stock purchase, researchers found.

"Specifically, trades of concentrated households perform significantly better than the trades of diversified households—even after controlling for households' average investment ability. The result is particularly strong for households with large account balances."

According to a study by Sialm and the Illinois researchers, stock picks of concentrated investors (those holding one or two stocks) outperform those of diversified investors (those with three or more stocks) by about one percentage point over the year following a stock purchase.

For households with relatively large portfolios ($25,000 or more), the difference in returns for concentrated versus diversified investors is three percentage points. For investors with portfolios of $100,000 or more, the difference is four percentage points. Purchases made by concentrated households with portfolios less than $25,000, however, fare no better than purchases made by diversified households.

In all, the link between performance and concentration does not mean that by simply altering one's portfolio to hold just a few stocks, performance will improve, the researchers say. Rather, it suggests that some investors with superior stock-picking ability exploit their skills by concentrating their portfolio in a few stocks.

U-M scientists see ubiquitin-modified proteins in living cells

Researchers at the Medical School and Howard Hughes Medical Institute (HHMI) have found a way to see proteins in cells that have been tagged by a molecular "sticky note" called ubiquitin.

"This technology allows us to see, under a microscope, proteins modified by ubiquitin inside the cell," says Tom K. Kerppola, associate professor of biological chemistry in the Medical School and an HHMI associate investigator. "Visualization gives us a direct connection to cellular processes that we could only study in test tubes or indirectly before."

In a paper published recently in the online edition of the Proceedings of the National Academy of Sciences, Kerppola and Dr. Deyu Fang, a U-M research investigator, describe the first use of a technology called ubiquitin-mediated fluorescence complementation to study a cell-signaling mechanism called ubiquitination.

In this process, a small peptide called ubiquitin is linked to a protein in ways that can change the protein's function and location within the cell. Originally, scientists thought ubiquitin was simply a universal "destroy me" signal for unneeded or harmful proteins, but it recently has been found to be associated with many other cellular functions.

"The same ubiquitin signal can cause one protein to be degraded, but another protein to be moved to a new location," Kerppola says. "We're interested in learning how this works."

To read more about their research, visit

Kerppola and Fang's research is funded by HHMI, the Human Frontiers Science Program and a grant from the National Cancer Institute to U-M's Cancer Biology Training Program.

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