As President Barack Obama approaches the end of his second term, he must find himself wondering (along with countless pundits) about his legacy. The results of a recent study suggest that the question of how long he will be remembered can be addressed scientifically. The rate at which the majority of the population forgets about presidents—and other cultural icons and events—follows a predictable pattern, according to Henry Roediger, principal investigator of the Memory Lab at Washington University in St. Louis.

Roediger and fellow Washington psychologist Andrew DeSoto studied the results of a presidential recall test issued to a total of 415 undergraduate students in 1974, 1991 and 2009, as well as a similar online test given to 497 adults, aged 18 to 69, in 2014. Participants attempted to recall as many U.S. presidents as possible and place them in the correct order.

Roediger found that people's patterns of forgetting were remarkably similar, regardless of their age or when they took the test. In general, people tend to remember the first few presidents, along with the most recent eight or nine presidents, and one or two presidents in the middle, such as Abraham Lincoln, who governed during distinctive events.

Even more surprising, Roediger says, is the fact that our memories tend to follow the same pattern for all information, not just presidents. One can draw a “forgetting curve” that applies equally to historical events, television shows and even personal memories.

“There's no reason that forgetting presidents should follow the same curve as forgetting a list of words,” Roediger says, “but that's what we see in the data.” As for Obama, the fact that he is the first African-American president means he will probably be remembered long past the 100 years or so that it will take for Bush and Clinton to become as obscure as Fillmore and Harrison seem today.

How Does Your Memory for Presidents Stack Up?

The test is simple: Write down as many presidents as you can name, in the order you believe to be correct. Then visit to see how your memorycompares with that of other people today and in the past.