Tweaks, not sermons, may be the most effective tools in promoting environmentalism.

"It's hard to change people's attitudes," says Sean Duffy, an assistant professor of psychology at Rutgers University-Camden. "But we can design our environment to make us better environmentalists."

Academics and environmental groups often rely too heavily on individual motivations, such as nature appreciation, to inspire people to act "green," Duffy said.

Practical changes to physical surroundings can coax the world into becoming a cleaner, greener place, said Duffy, who recently published a study on recycling habits in the journal Environment and Behavior.

That belief is at the core of a growing number of South Jersey grassroots initiatives.

In Cherry Hill, some municipal workers groused when their desk trash cans were removed over the summer, forcing them to deposit office paper in a special receptacle. Now they're proud of their recycle-first mandate.

And six organizations are working with New Jersey's Board of Public Utilities and Clean Energy Program to transform habits one lightbulb at a time.

Better "green" design results in greater compliance and more efficient use, Duffy said.

Want people to walk more? Build sidewalks, he said.

Want them to use mass transit? Build houses near train lines.

As for recycling, cut a hole in a trash-can lid, and many people will deposit their cans and bottles in it, Duffy discovered in an on-campus experiment.

When a student asked him for suggestions on improving Rutgers-Camden's recycling rate, Duffy and Michelle Verges, an assistant professor of psychology at Indiana University-South Bend, researched the effectiveness of public recycling containers.

"Somewhere we've learned that a hole means recycling," Duffy said. "It's sort of fun. Maybe it reminds us of a childhood game."

A six-inch opening in the lid of an identical can increased the volume of recycled bottles and cans 34 percent, and with less trash mixed in, Duffy found in the month-long study of 30 receptacles in Rutgers-Camden's Armitage Hall.

Researchers consider a 4 to 5 percent behavioral change significant, he said.

Such statistics are unavailable in Cherry Hill, where a municipal initiative replaced the desk-side trash cans of 300 workers with individual paper-only cans. But employees say they are recycling a lot more paper.

"It's a pain, but we do it," said Deborah Campbell, the township's chief financial officer. "We know it's for the greater good."

A paper cup on clerk Dawn Regan's desk was filled with staples and an apple core last week. She empties her garbage and trash once or twice a day into a centrally located container in the controller's suite.

"It makes you think about every piece of trash you make, every granola-bar wrapper," said Jennifer Kelley, who works in Mayor Bernie Platt's office.

Cherry Hill, which last week won a Governor's Environmental Excellence Award for its Green Action Plan, also is trying to change lighting habits. It is working with Project Porchlight, an effort to persuade people to try compact fluorescent bulbs. About 50 volunteers distributed 2,000 free bulbs door to door on Nov. 16. Eighty were given out - one per family - at the Township Building.

"We're so used to thinking we're insignificant," said Amy Milgrim, a volunteer and board member from the community group Sustainable Cherry Hill. "These things that seem really little really make a difference."

Another group, HelpLightNJ, will distribute compact fluorescents today at the Nancy Elkis Senior Center in Deptford in a similar program. Residents of the Gloucester County Housing Authority will receive more than 14,000 bulbs.

Students from Deptford High and Mater Dei High in Monmouth County will hand out the last of 60,000 bulbs the student-founded HelpLightNJ received from a state Clean Energy grant.

Low-income residents will receive free six-packs, valued at approximately $30. The bulbs use about 70 percent less energy than incandescent bulbs and last up to 10 times longer. The six-pack can save families $400 off their electric bills over their lifetime.

"Give them a bulb, and see if it changes their behavior. It's a great idea," Duffy said. "You don't have to go to extremes to be an environmentalist."

Sandi Lichtman, a Cherry Hill real estate broker, campaigns to reduce plastic-bag consumption. A user of canvas bags for at least 10 years, she recently wrote to Barnes & Noble to request that clerks ask customers if they want a bag, rather than automatically offering one.

"It's very slow going to change the psyche of a large group of people," Lichtman said.

Contact staff writer Cynthia Henry at 856-779-3970 or chenry@phillynews.com.