Psychologist finds ways to better track aging and cognitionBy Wayne Lewis
May 1, 2006
Sometimes Jack McArdle can feel like a man in-between. “In a multidisciplinary way, I’m in the middle of many things,” said the USC College psychology professor. “When I’m with the statisticians they think of me as a psychologist. When I’m with the psychologists they think of me as a statistician.”
He smiled and added, “It’s not that I mind. It turned out that combining a focus on research methodology with the study of cognition was better than either one alone.”
The National Institute on Aging (NIA) apparently agrees. McArdle, who recently joined the College faculty, has received a prestigious MERIT award from the NIA. His work combines his expertise in statistics and research methodology with his training in human cognition and aging. His goal is to better understand how and why cognition changes as people age by improving the way intellectual ability is measured.
The MERIT award will support his work with the Health and Retirement Study (HRS), an existing longitudinal survey based at the University of Michigan that retests its participants, people across the nation over age 50, every two years to track changes over time. The sheer size of their database, which is available to researchers across the country, provides an exciting opportunity to generate new results and powerful conclusions. Eventually, the data could yield reliable information about risks that accelerate age-related declines — and lifestyle choices that can slow these declines.
McArdle is appropriately ambitious. “We have this large sample, and a chance for a lot of different impacts on lifestyle and health by arming people with knowledge. Essentially the base here at USC will provide cognitive measures for the world. To measure the intellectual ability of the world, that’s our goal.”
His successful track record as director of the National Growth and Change Study (NGCS), which measures and analyzes cognition over time in about 1,000 older adults, helped earn McArdle the MERIT award. McArdle has described his current task as merging the HRS with the NGCS.
“Now [the HRS] had memory already, but that’s about it,” said McArdle. “They really didn’t test for the full range of thinking and how fast things can be done. So they asked me, ‘What else can we do?’ and we introduced tests that are more sensitive to the age declines that are important.”
McArdle employs a model for measuring intellectual ability adapted from the work of his mentor, John Horn, also a member of the College’s psychology faculty. Rather than relying on a single factor, like the result of an IQ exam, McArdle’s multivariate research uses tests that score participants across eight factors: acquired knowledge; fluid intelligence, or problem-solving skill; visualization; auditory abilities, or the assimilation of heard information; long-term memory; short-term acquisition and retrieval; speed of processing; and numeracy, or quantitative ability.
“This model has been tested in a rather rigorous way,” said McArdle. “As it turns out, a person that’s high in one ability is not high in every one — there are strengths and weaknesses due to neurology, due to education, due to life circumstances. They fluctuate too, so not everyone’s the same each day.”
The grant McArdle received, the NIA’s Method to Extend Research in Time Award, is bestowed on fewer than 5 percent of all grantees each year. There is no application process for the MERIT award, and only established grantees with 20 years of funded research are eligible. The award will provide McArdle five years of funding for his work with the HRS, with the opportunity to seek renewal.
According to Dr. Jeffrey Elias of the NIA’s Behavioral and Social Research Program, “The results and methods derived from this research are expected to drive forward the fields of cognition and aging, survey methods and statistical analysis for years to come.”
“It was a big surprise,” said McArdle. “They liked this project enough to give it a special boost. This is a very large-scale project, and the NIA is looking for this to be the U.S. national project on intellectual ability. And I’m very pleased — I’ve been wanting to do this for quite a while.”
As might be expected of an expert in both research methodology and the questions of cognition and aging, McArdle has an interdisciplinary background. He earned his undergraduate degree in psychology and mathematics from Franklin & Marshall College in 1973, immediately going on to doctoral studies in psychology and computer sciences at Hofstra University.
After receiving his Ph.D. in 1977, McArdle did postdoctoral work at the University of Denver under the tutelage of John Horn. In 1983 McArdle went on to join the faculty at the University of Virginia. Horn would depart Denver for USC College in 1987.
McArdle gives a great deal of credit to his mentor. “He really made some breakthroughs in the late ‘60s. When it comes to the study and measurement of cognitive ability, John’s really the leader. I’m the follower putting his ideas into play.”
Horn returns his one-time protégé’s esteem. “When Jack came to work at University of Denver he gave much more than he got,” he said. “The department blossomed with fresh sophistication in multivariate methods and multivariate substantive theory. Jack was the person who sowed and nourished that flowering.”
After more than 20 years in Virginia, McArdle was hired at USC College in 2005. He was recruited, along with his wife, behavioral geneticist Carol Prescott, as part of the Senior Faculty Initiative, Dean Joseph Aoun’s bold plan to hire 100 world-class senior faculty to help boost the continuing rise of the College’s academic programs. The chance to reunite with Horn was one of many incentives that brought McArdle to USC.
“This is a very good place to do this kind of work. There are wonderful colleagues here, both in psychology and gerontology, that aren’t anywhere else. It’s simply a super group of people. I thought, frankly, that my research would work best here in the next 10 years.”
In addition to being a prominent researcher, McArdle is lauded for his skills as a teacher. “His classes are packed,” said Kelly Kadlec, a postdoctoral fellow in McArdle’s laboratory. “To have him in the classroom for a whole semester, it’s an amazing thing.”
McArdle, who also serves as the head of the College’s quantitative psychology program, encourages his students with diverse interests in the sciences to start with the basics of research. “Anybody who’s really interested in many disciplines should study methods,” he said, “because methodology is the way to clear up all the confusion. It’s almost all the same, in so many disciplines. That’s the Rosetta Stone — methodology.”