If you're like Einstein, you respond to some e-mails immediately and let others wait. And, of course, some you never answer.
And every now and then, you find an old one in your inbox that you didn't even realize you had, and you reply.
Einstein sent more than 14,500 letters. But he received more than 16,200, and responded to only a quarter of them. Darwin mailed more than 7,500 letters. He responded to 32 percent of the roughly 6,530 letters he received.
Of course letter writing takes more time than e-mail, but the mathematical relationship between quick replies and delayed responses was similar, explains João Gama Oliveira of the University of Aveiro (search) in Portugal.
Of Einstein's responses, 53 percent were sent within 10 days. For Darwin, the figure was 63 percent. But now and then they replied months or years later. Einstein begins one reply by explaining that he's just discovered the sender's letter of more than a year prior while sifting through "a mountain of correspondence."
"In both Darwin's and Einstein's correspondence, and today's e-mail, we find that most responses take short time, but sometimes the responses take a very long time," Oliveira told LiveScience. "In other words, for both e-mail and mail communication, the response times exist in a very broad range of values, and there is no typical response time for which we could say that all response times are around (and close to) that value."
The result suggests Darwin, who conceived the idea of natural selection in evolution, and Einstein, father of modern physics, must have prioritized their letter-writing, say Oliveira and his colleague, Albert-László Barabási of Harvard University.
"Their timely responses to most letters show that they were both aware of the importance of this intellectual intercourse," Oliveira and Barabási write in the Oct. 27 issue of the journal Nature.
The upshot: Einstein and Darwin exhibited a "fundamental pattern of human dynamics" that plays out every morning when you check your inbox.
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