A quick sociological reference, bridging between '(social)
identity' and '(practical) role' might be:
Kaj Ilmonen  
The Use of and Commitment to Goods
(2004) Vol. 27 No. 4 Journal of Consumer Culture
though it is more focused on consumer use than expert
equipment use.

[Heidegger-phobes should skip the next paragraph]
A not-so-quick philosophic reference would be Heidegger's
_Being and Time_. What is at issue in much of B&T is
Heidegger rethinking Husserl's intentionality through the
notion of relationality. There are three aspects to this
notion: 
1) no thing can be understood in isolation; some thing
makes sense only in relation to all the other things that
it is used with, the 'design ecosystem' of all the gear in
the tool room of a carpenter or a webdesigner or a sleeper
2) understanding a thing means being involved with a thing,
knowing how to use it, being able to rely on it, being familiar
with it, i.e, being in a relation with it - to the extent that
only an X-er can be said to really understand an X; a hammerer
a hammer, a coder a code, a sleeper a pillow (which is why you
can say, much to plain-speakers chagrin, 'a thing things').
3) this is the everyday way of understanding, one that is
more or less in the background, as how we go along with the
world, coping rather than contemplating; which is why it can
be characterised as a role, or by collective identities -
when I hammer or webdesign or sleep, I am not (uniquely) me,
but one of They that understand hammer(ing)s, design(ing)s,
or sleeping(beds). To put it the other way around, to suddenly
be without my gear (like fire fighters dropping their equipment
or a surgeon when the machine that goes ping breaks) is to be
exposed to my sheer existence, a source of existential anxiety.
I have been trying to paraphrase John Haugeland's famous
(at least amongst Heidegger-ers) essay
"Heidegger On Being a Person"
(1982) Vol. 16 No. 1 Nous

Interesting applied research on this is Phil Turner's work
on familiarity in relation to HCI usability - in hasty para-
phrase, you need to think of yourself as a computer-user
_before_ and _in order to_ learn how to use a computer:
Van de Walle, G., Turner, P. and Davenport, E. (2003). The Phenomenology of
Familiarity. In , INTERACT 2003 - Bringing the Bits togETHer
http://www.idemployee.id.tue.nl/g.w.m.rauterberg/conferences/INTERACT2003/IN
TERACT2003-p463.pdf
  
A question that Heidegger's account of being-in-the-world
raises is the extent to which what or how things are lies
with things (their functional qualities[1], their script-cues[2],
their semantics[3], their affordances[4]) or with people (their
skills and competencies) - in other words, are these just symbols
on products, or symbolisations that people give products in use
(hence lay theories like 'if you hit it there it sometimes starts
to work again').
See
Paul Kockelman
"Residence in the world: Affordances, instruments, actions, roles, and
identities"
(2006) Issue 162 Semiotica

1 See www.dualnature.tudelft.nl
2 See Latour's ANT
Akrich & Latour (1992) - A Summary of a Convenient Vocabulary for the
Semiotics of Human and Nonhuman Assemblies, Ch 9 of Bijker & Law (1992) -
Shaping Technology / Building Society: Studies in Sociotechnical Change,
summarised at 
http://www.conceptlab.com/notes/akrich-latour-1992-convenient-vocabulary.htm
l
3 See Krippendorf's work
http://en.wikipedia.org/wiki/The_semantic_turn
(This article or section is written like an advertisement)
4 See Alan Costall's work:
http://tap.sagepub.com/cgi/content/abstract/5/4/467

-- 
Assoc.Prof. Cameron Tonkinwise
Chair, Design Thinking and Sustainability
School of Design Strategies
Parsons The New School for Design
Co-Chair, Tishman Environment and Design Center
Room 325, 65 5th Ave, New York, NY 10011


> I'm looking for a reference that perhaps you can help me with. I'm trying to
> understand how symbolic cues embedded within designed artifacts can
> communicate things pertaining to the identity of the individual or group
> that is using them.  My thinking goes back to some philosophical work I read
> by, I think it was Husserel, who talked about a tool being defined by its
> function(s) rather than its properties.  I read another paper  describing
> how firefighters were instructed to throw down their gear and run from a
> fire that had blown out of control. The author argued that without their
> tools, the individuals were no longer firefighters, but became simply
> victims running away from a fire. I came across a paper on surgeons
> responding to a clinical information system and feeling its clerical
> functions did not align with the activities embedded within their identity
> as a surgeon:
> 
> Sometimes I recall that the reason why I chose the profession and job was
>> because I wanted to be a craftsman ­ you know, to take care of hip
>> replacements. Everybody in my profession is characterised by being a
>> carpenter, a bricklayer, a butcher, a seamstress at the same time. Being
>> placed in front of a computer is not natural to me.
> 
> 
> I'm looking for references that might discuss how a designed object can
> communicate its function to a user, and how those functions influence 1) the
> identity of the person using it, and 2) the collective identity of multiple
> persons using it simultaneously.