If your mother gets sick during long car rides, does that mean you too may need to pull off the road between Pittsburgh and Philadelphia? If you feel nauseous after riding on the merry-go-round with your son, is he likely to feel the same?

According to Manda Williamson, former doctoral student in psychobiology at Penn State, the answer may be yes. Williamson's research suggests a potential link between motion sickness and genetics.

James Collins

"Our lab started by testing personality, gender, and age as explanations for why certain individuals are affected by motion sickness, and others are not," says Williamson. "No interesting data were found, so the team moved on to race. That's where the first interesting discovery was made."

Robert Stern, distinguished professor of psychology at Penn State, collaborated with graduate students to conduct lab tests for motion sickness on healthy college students of Asian, African-American, and Caucasian-American decent. Each student was placed in a rotating drum to create an illusion of motion, although the student was actually sitting still. Results showed that 80 percent of Asians experienced motion sickness, while less than 50 percent of African-Americans and/or Caucasian-Americans were affected.

An additional study was conducted by Krishna Sharma from Panjab University in Chandigarh, India. Sharma and his team of researchers tested 200 twin pairs from India. They found that if one identical twin experienced motion sickness, the other twin was 100 percent likely to be similarly affected.

Intrigued, Williamson conducted a follow-up study using the data from Sharma's study. She found that if both parents were susceptible to motion sickness, their children were five times more likely to also have motion sickness.

While Williamson concedes that such a result could be partially explained by environmental similarities in the twins' upbringing, she notes that the high degree of correlation suggests at least some genetic influence.

Research suggests that different individuals require different amounts of time to adjust to new sensory environments, such as a moving car or a whirling merry-go-round. "The genes required for people to adapt to these new situations may 'turn on' faster in some than others," Williamson speculates. "If we can build tolerance in those who are most affected by motion sickness, even slow adaptors can train their genes to respond and adjust to the situation."

"I believe there is a genetic basis to motion sickness," she adds, "and my hope is that some day this line of research will allow us to manage motion sickness for the people who are most affected by it."

Manda Williamson received her Ph.D. in psychology from Penn State in 2003. She is now an assistant professor of psychobiology at the University of New England in Biddeford, ME; mwilliamson@une.edu. Robert Stern, Ph.D., is distinguished professor of psychology; rs3@psu.edu.