Since the original (now quite old) piece is very short, and the author gives permission for reproduction with copyright notice, I will also cut and paste it here:
I came up with this idea several years ago in a conversation with a friend at MIT, who was regularly finding herself upset by other people who worked in her lab. The analogy worked so well in helping her to understand her co-workers that I decided to write it up and put it on the web. I've gotten quite a few email messages since then from other people who have also found it helpful.
All people have a "tact filter", which applies tact in one direction to everything that passes through it. Most "normal people" have the tact filter positioned to apply tact in the outgoing direction. Thus whatever normal people say gets the appropriate amount of tact applied to it before they say it. This is because when they were growing up, their parents continually drilled into their heads statements like, "If you can't say something nice, don't say anything at all!"
"Nerds," on the other hand, have their tact filter positioned to apply tact in the incoming direction. Thus, whatever anyone says to them gets the appropriate amount of tact added when they hear it. This is because when nerds were growing up, they continually got picked on, and their parents continually drilled into their heads statements like, "They're just saying those mean things because they're jealous. They don't really mean it."
When normal people talk to each other, both people usually apply the appropriate amount of tact to everything they say, and no one's feelings get hurt. When nerds talk to each other, both people usually apply the appropriate amount of tact to everything they hear, and no one's feelings get hurt. However, when normal people talk to nerds, the nerds often get frustrated because the normal people seem to be dodging the real issues and not saying what they really mean. Worse yet, when nerds talk to normal people, the normal
people's feelings often get hurt because the nerds don't apply tact, assuming the normal person will take their blunt statements and apply whatever tact is necessary.
So, nerds need to understand that normal people have to apply tact to everything they say; they become really uncomfortable if they can't do this. Normal people need to understand that despite the fact that nerds are usually tactless, things they say are almost never meant personally and shouldn't be taken that way. Both types of people need to be extra patient when dealing with someone whose tact filter is backwards relative to their own.
Copyright © 1996, 2006 by Jeff Bigler. Permission is granted to redistribute this text in its entirety, provided that this copyright notice and either the URL for the page (http://www.mit.edu/~jcb/tact.html) or a link to it is included. All other rights reserved.