Paying extra bucks to "go green" in a hybrid car may pay off in self-esteem and image for older drivers, as well as give a healthy boost to the environment, according to a Baylor University study.

The finding is significant because some segments of the older-consumer population control a considerable share of the discretionary income in the United States, and the population size of the "mature market" is growing rapidly, researchers said.

The study is published in the journal Human Factors and Ergonomics in Manufacturing and Service Industries.

"If I want to pay $5 for a 'green' detergent or sponge, I'll know that I'm helping the environment. But those things aren't highly visible. Other people aren't going to notice," said Jay Yoo, Ph.D., an assistant professor of family and consumer sciences in Baylor's College of Arts and Sciences.

Researchers analyzed a national cross-sectional survey of 314 consumers age 60 and older who had bought hybrid cars. The study showed that their satisfaction was influenced by social values -- including pride and prestige -- as well as quality and price, not only in vehicle purchase but in future savings on gasoline expenses.

Those three variables -- social value, price and quality --are significant in enhancing senior citizens' customer loyalty as shown by repurchase intention and positive word-of-mouth, Yoo said. Emotional values -- such as excitement - did not significantly influence their purchase intention or satisfaction, according to the study.

"The findings suggest that elderly consumers are concerned about how they appear to others when driving a hybrid car," the researchers wrote. "They believe that driving a hybrid car builds a positive self-image of the people who drive them."

"This knowledge can help as a marketing tool," Yoo said. "Hybrid cars have increased in visibility because of their environmental consciousness. So people may be willing to pay an extra $5,000 or so in order to think, 'I'm great, and this is good for the environment.'"

Previous research has shown that older consumers are more inclined to behave in a pro-environment way than younger generations are, Yoo said.

Other researchers were Won-Moo Hur of the School of Business Administration, Pukyong National University in Busan, South Korea; and Jin Hur of the Yonsei School of Business, Yonsei University, in Seoul, South Korea.