You may feel like you're not in the same league as Albert Einstein or Charles Darwin (note: statistically, you are not)  but you probably share one thing if you are reading this article; patterns of correspondence.

A new Northwestern University study of human behavior says that people who wrote letters in olden days using pen and paper did so in a pattern similar to the way people use e-mail today.  The study in Science seeks to find the similarity of these two seemingly different activities, with the underlying pattern of human activity linking letters and e-mails.

The researchers examined extensive letter correspondence records of 16 (in)famous writers, performers, politicians and scientists, among them Einstein, Charles Darwin, Sigmund Freud, Karl Marx and Ernest Hemingway, and found that the 16 individuals sent letters randomly but in cycles.   The same mathematical model the Northwestern team used in a previous study to explain e-mail behavior was shown to also apply to the letter writers. That refutes the 'rational model', which says that people are driven foremost by responding to others.

No matter what their profession, all the letter writers behaved the same way. They adhered to a circadian cycle; they tended to write a number of letters at one sitting, which is more efficient; and when they wrote had more to do with chance and circumstances than a rational approach of writing the most important letter first.

"We are interested in identifying and understanding patterns of human behavior, in learning how we make choices," said Luís Amaral, professor of chemical and biological engineering in the McCormick School of Engineering and Applied Science. Amaral led the research. "There are patterns to how we spend our days, and these models of probability, of how people allocate their time to do certain tasks, can be applied to many different areas."

"People are not that rational," added Amaral, who also is an Early Career Scientist with the Howard Hughes Medical Institute. "If a doctor, for example, better understands how we make decisions, he or she may be able to get better compliance with a treatment if it is tied to something a person does with regularity."

The researchers studied correspondence that dated as far back as 1574 for philosopher Sir Francis Bacon and as recently, in the case of writer Carl Sandburg, as 1966. The letter data for the 16 individuals included a list of letters sent and, for each letter, the name of the sender, the name of the recipient and the date it was written.