Platitudes can change attitudes. For example, those who regularly count their blessings really do become more content.

That's a conclusion Michael McCullough has reached after a decade of researching positive emotions.

"Gratitude looks like an engine for happiness in general," he said.

Dr. McCullough, who teaches psychology at the University of Miami, will lead a seminar on the psychology of gratitude Thursday at a most appropriate forum – Dallas' Thanks-Giving Square.

The Philip Johnson-designed chapel of that ecumenical research center was consecrated in 1976. But the center traces its roots to 1907, when a small group of Dallas clergy – Protestant, Catholic and Jewish – decided the city should have a community Thanksgiving service.

To celebrate a century of interfaith thanksgiving in Dallas, Thanks-Giving Square is having events throughout the year, and Dr. McCullough's is among the first.

The seminar is meant to be scholarly but also accessible and practical.

"People are really suffering from so much fear and anxiety in our day. Gratitude can break into that," said Katherine DeGrow, a member of the Interfaith Council of the Thanks-Giving Square Foundation and a planner for Thursday's seminar.

Dr. McCullough, 37, taught at Southern Methodist University before moving to Miami. He is the co-editor of the book The Psychology of Gratitude.

He got in early on what's often called the positive psychology movement. Here, psychologists' traditional focus on negative emotions and conditions, such as depression and addiction, gives way to trying to understand what underlies and fosters happiness.

When he started looking at gratitude in the late 1990s, Dr. McCullough said, the psychological literature on the subject amounted to a few not-very-helpful articles, all of them theoretical.

He read the spiritual literature related to gratitude, which he found to be contrastingly rich. And with colleagues, he began to set up studies aimed at pinpointing how gratitude works as an emotion, and whether grateful people have other traits in common.

"What we came down to is pretty simple," he said. "Grateful people are kind of prone to positive emotions in general. They're happy people, and they tend to be spiritual people. They look at creation and see a world filled with love.

"They look at a building and think, 'Man, a lot of people put a lot of work into creating the infrastructure we enjoy every day.' "

Dr. McCullough and two colleagues came up with a simple test to measure whether an individual is more or less grateful than most folks. He also helped devise a study of whether gratitude, when cultivated through habit, leads to increased happiness.

The study involved three groups of people. One group spent five minutes a day, for 14 days, listing things they were grateful for. Another followed the routine but wrote about hassles in their lives, and a third recorded neutral events.

The grateful group proved to be the sunniest.

"If you do this simple little exercise, basically count your blessings, you're going to be happier as a result," Dr. McCullough said.

The positive psychology movement has critics. Among them is Julie Norem, a Wellesley College professor and author of The Positive Power of Negative Thinking.

She says that the positive psychologists have done much good research, but she accuses some of oversimplification and taking a "one size fits all" approach to advice. Her research, for example, shows that anxious people do better if they employ "defensive pessimism" than if they force themselves to be optimistic.

Though not closely familiar with Dr. McCullough's work on gratitude, she offered this caution in an e-mail interview:

"Sincerity, rather than going through an exercise, would seem to be the key to me, and the part that's likely hardest for those who already tend to take what they have for granted. I'm in no away 'against' gratitude. It's just far from a cure-all or magic bullet."

Dr. McCullough acknowledges that in some ways gratitude is a complicated emotion. His studies on whether grateful people are less materialistic than others have proved inconclusive.

That has led him to feel another positive emotion – humility.

"We did one study where it looked pretty clear that grateful people were less materialistic. With other studies, the evidence wasn't so strong," he said. "I really don't understand what's going on."

Michael McCullough's seminar on gratitude will be from 11:30 a.m. to about 2:30 p.m. Thursday at Thanks-Giving Square, 1627 Pacific Ave. Tickets are $25, including lunch. Space is limited. Call 214-969-1977 for reservations.