“How can you tell when an engineer is an extrovert?”/“He stares at YOUR shoes when he talks to you.”

A popular joke told about engineers (and actuaries and probably many other professions) is:
 
Q: How can you tell when an engineer is an extrovert?
A: He stares at your shoes when he talks to you.
 
The joke has been cited in print since at least 2000.
   
 
Google Groups: comp.os.linux.setup
How to Partition for best Linux operation & security
Colin Watson
2/17/00
(...)
“How can you tell an extroverted software engineer?”
“He looks at *your* shoes when he talks to you.”
     
Ars Technica
Geekiest Joke *Ever*!
Spiv
Posted: Thu Jan 10, 2002 10:25 pm
how can you tell the difference between an introverted engineer and an extroverted engineer?
An extroverted engineer stares are your shoes when he talks to you.
 
Google Groups: alt.usage.english
Where is the subject?
Jerry Friedman
11/7/05
This reminds me of something I heard from a friend of mine, a math teacher:
 
How can you tell whether a mathematician is an extravert?
 
He looks at *your* shoes when he talks to you.
 
Google Groups: comp.soft-sys.sas
OT Friday Humor: An Extroverted SAS Programmer
Michael Raithel
6/22/07
Dear SAS-L-ers,
Here is a joke that I picked up on my trip to BASUG, earlier this week:
 
Q:  How can you tell that you are speaking to an extroverted SAS programmer?
 
A:  Because he is looking at _YOUR_ shoes when he talks to you.
     
30 September 2007, New York (NY) Times, “Re-engineering Engineering” by John Schwartz, pg. E94, col. 1:
Richard K. Miller, president of the school (Franklin W. Olin College of Engineering in Needham, MA—ed.), likes to share a professional joke: “How can you tell an extroverted engineer? He’s the one who looks at your shoes when he talks to you.”
 
Twitter
Pete Warden
‏@petewarden
@aiderss They’ll be fine, I just found dressing like an engineer made me behave like one- an extrovert engineer stares at your shoes not his
2:24 PM - 30 Oct 2008
 
Twitter
Luke Nihlen
‏@lnihlen
Q: how do you tell between an introvert and an extrovert programmer? A: the extrovert programmer stares at your shoes when talking with you.
12:50 AM - 17 Aug 2009
 
Twitter
Tom France
‏@tfrance
How can you tell that a software engineer is an extrovert?  He stares at YOUR shoes when he talks to you.
10:36 PM - 26 Aug 2009
 
Google Books
Thinking Like an Engineer:
An Active Learning Approach
Edited by Elizabeth A. Stephan
Boston, MA: Pearson
2011
Pg. 71:
Here’s a joke: “How can you tell an extroverted engineer?” “He looks at your shoes when he talks to you.”
   
27 February 2015, FT.com (Financial Times), “Feedback: perils of jokes on trips abroad”:
How can you tell if you are speaking to an extroverted accountant? He looks at your shoes when he talks to you. (Also works with actuaries).
 
Google Books
By the Numbers
By Jen Lancaster
New York, NY: New American Library
2016
Pg. 5:
I mean, one of the biggest jokes regarding my profession is, “How can you tell when you meet an actuary who’s an extrovert? He looks at YOUR shoes when he talks to you!” so we’re not exactly famous for being toastmasters.