Actually I was curious about the same thing. The colors are based on your field of study. Olive green is specific to pharmacy/medicine it seems like, purple is law, dark blue of philosophy etc.. Doctorate gowns have the three stripes that you see, and you get a hood with a matching color. The hood also has color accents of your school colors, so my hood has stripes of gold and black. The cords are from my different organizations and achievements. Kind of interesting how there is a whole tradition with regalia.
I am guessing they all went to my alma mater - Berkeley!
Thanks for all the info. Berkeley, gee you think?
Yes, back in the day, not only was Berkeley the best choice within most peoples' incomes, it was one of the only choices for post bachelor's work in northern California. My MBA friend from Cal got no hood, or colors, just a black gown and a piece of paper. My cousin got his BS degree from there with just a tie, and no gowns as that was very anti-Berkeley at the time. Anything being worn that resembled anything traditional actually put you in threat of physical harm back then as there was a real cultural civil war in America but it was being played out to an extreme extent at Cal that nobody here would ever understand. Students and teachers, if they were vocal against the Vietnam war, were arrested and beaten by the Berkeley police and any free speech was seen as a communist plot. just weird stuff
The last time I visited the campus, they still had the clothing optional rule for campus but only one old school hippie student walked around nude back then in the 1990s. I would hate to think what he looks like now if he is still a perennial student.