In various situations, sign language is used spontaneously by HEARING-ABLE people, e.g.
Drivers in vehicles signalling to each other. The only research into sign language I have been able to find 'on the NET' relates specifically to 'deaf' people. How/where would I find discussions about the other type - it would EX-clude 'Morse flag waving' and pennant flying, as these are not SPONTANEOUS.

Well I get a lot of hand signals while I am driving, they normally get their point across.

What an interesting question!

Here's one link with blue words that can be clicked depending on what you want to find out:

Manual communication - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Manual_communication)

More by googling "driver sign language" (without the quote marks) --

Halfbakery: Drivers sign language (http://www.halfbakery.com/idea/Drivers_20sign_20language)

"nonverbal communication" --

Nonverbal Communication (http://www.fhsu.edu/~zhrepic/Teaching/GenEducation/nonverbcom/nonverbcom.htm)

Nonverbal Communications (http://www.blatner.com/adam/level2/nverb1.htm)

About.com: http://nonverbal.ucsc.edu/ (http://humanresources.about.com/gi/dynamic/offsite.htm?zi=1/XJ&sdn=humanresources&cdn=money&tm=11&f=20&su=p532.7.150.ip_p554.2.150.ip_&tt=2&bt=0&bts=0&zu=http%3A//nonverbal.ucsc.edu/)

Thank you, WonderGirl, for those 'links'. They look more promising that what I have so far found. The term 'non-verbal' seems to produce more results than 'sign' - although it is specifically SIGNING that interest me. I would have thought there would be a branch of psychology dealing with this topic. I will follow up your suggestions when I again get access to high-speed broadband connection (tomorrow ?). My dial-up here at home is useful but 'a pain'.

I would have thought there would be a branch of psychology dealing with this topic.

Psychology HAS done research on non-verbal communication (facial expressions, body language -- as shown in one of those links) and stresses that to therapists-in-training, to pick up cues from clients/patients who say one thing and physically "show" something else. (I took several classes on this in psych grad school. For instance, I had a college-age client who came to me and said there was really nothing wrong in her life. As she said this, she put her feet up on the chair and wrapped her arms around her legs and buried her head on top of her knees. Turned out both parents had died within the past year, one of cancer and the other in an accident.)

Psychologists and psychiatrists (Oliver Sacks for one) have studied the unique sign language that develops between a set of twins, in a dysfunctional family, at the mental health facility between patients and between staff and patients, between primates and people, in animal families.

Please feel free to become more specific with questions or comments on this subject. It truly is a fascinating one!

WonderGirl
I've had the acces to fast broadband, and looked up the links you gave me. I retract my complaint about the dearth of material on this topic. I will not be following up your invitation to go deeper, as mine was a superficial fascination with the effectiveness of SPONTANEOUS signing, especially the great speed at which is it solicited in time of need.