What is the origin of the idiom "wearing the < role > hat"?
Here is an example from the post Getting things done when you wear multiple hats in PookieMD's Blog:
I wear many hats, and I suppose you do as well. I wear my small business owner hat when I run/manage my company, ExtraMD, my doctor hat when I play doctor, and my consultant hat when I head off to multiple meetings that seem to define the EHR consultant world I live in. Of course, I wear my mother hat, wife hat, Girl Scout leader hat, and the hat that seems to get worn the least–the self hat.
and another example from Jean Scheid's The Many Hats of a Project Manager:
As the owner of a small auto dealership, many of my managers wear more than one hat. My service director is also my parts director and my finance manager is also my sales manager. In the business office, my controller has an added responsibility of obtaining registrations for the vehicles we sell.