We read that a functioning, healthy adult brain is an extremely complex item. But from that fact, I think it is surprising that in addition to being complex, such a brain can and does engage in lots of communication. We usually think of communication as being like a spoken conversation, a little bit from A and then a little answering bit from B. Longer times between exchanges and longer exchanges are possible, too. If I read poems written in an earlier century in a language I don't know but translated by someone who does know that language, that is long range communication, too. It ranges across time that is longer than a human lifetime and involves that human function of translation.
When I get a phone call, I may choose to not answer it. I do have an answering machine that records spoken messages I don't receive live. These days, I still have email that can transmit written messages and photographs, including videos but it is all the fashion to send and receive text messages, which depend on a different technology than email.
That is already three systems: voice, email, text. It seems to me that my friends and relatives, not to mention advertisers and propagandists of all sorts, use all three and more or less keep straight what they receive and what they transmit on all three. I know four women who write letters on paper and drop copies in a mail box to each other once a month. They have been doing that regularly for about 15 years. So that makes four complete systems, each of which is capable of sending and receiving messages. Then, there is the old-fashioned system of going to someone's house and ringing the doorbell.
