The SURGED quality, while a power-gamer's dream, offers a plethora of choices for character variation. I really like the idea of Mood Hair ( ), and for a long time now I've played around with the idea of a (relatively) simple system for the colors changing. When I've taken the quality, it often just sits there on the sheet and gives me points. What I want is something to make it easier for the player / ST to know, at any given time, what color the hair would be. That way the changes can be incorporated into descriptions, and hopefully be more evident, thus leading other characters naturally towards guessing the secret.

What I did was postulate a theory that the chemicals which regulate hair color, Eumelanin and Pheomelanin are, for the SURGED character, affected by the mood chemicals adrenaline and serotonin respectively.

Hair would be white (relaxed) in the absence of all four chemicals.

As your adrenaline rises, your hair would become either more brown (aggression) or more black (fear). Blondes and greys would lay between the two extremes.

As your serotonin rises your hair becomes redder. The final color would be determined by your relative levels of stress / satisfaction. Controlled fear (like watching a horror trid) or exhilaration (riding a coaster) would max both shades, resulting Auburn or Red-Orange hair respectively.

I like this idea. Adds some execution to the existing concept, is pretyt simple.

not sure why you decided to stick to the standard human array of colors, except if that is someone's preference. Our troll has primary colors, so you can't miss it. No reason not to, just curious.

There are a number of other emotions, however, that would show up and cause a response on something like a polygraph, that haven't been mentioned. Specific chemical indicators may be irrelevant. Some you might have a hard time getting a recognizable blend.

Real-life emotions that result in drastic behavior:
Disgust *
Fear *
Happiness
Anger *
Sadness
Surprise *
Amusement
Contempt *
Contentment
Embarrassment *
Excitement
Guilt *
Pride in achievement
Relief
Satisfaction
Sensory pleasure
Shame *

These are facially classified emotions (emotions that tell in the face) as described by Paul Ekman (whose work inspired the TV show Lie to Me). Not all of these are immediately pertinent to shadowrun, but the ones with the asterix I would personally think are ones shadowrunners wish they could see.
http://en.wikipedia.org/wiki/Paul_Ekman
the wiki page has some good general info about the history, but nothing very relevant to this thread I think.

A character with good Con/negotiation/fast talk might be very good at hiding his actual feelings so there is no visual reaction to the facial muscles or eyes - but a trained eye would react to how his hair would suddenly shift colours depending on questions and would after a few meets manage to gauge reactions and see how the character feels about something.