I was wondering... are there any resources to help Referees role-play different character types? It would be really useful as I have no theatrical / acting background.
I think it's a combination of things, and your question is secretly a bit like an onion, as there's many layers to it we could peel at.
If you're talking about
acting out NPCs, as in
interpreting them... I think it bears reminding you that it's not really necessary. Part of the power of Consensual Mass Hallucination/TTRPGs is that as it is all played out in the theatre of the mind, you can do a lot to 'act' out a character via descriptions alone. You don't really need to embody a whole other person faithfully, simply narrate it.
Which brings us to the next layer: to be able to 'portray' a character in a convincing manner (be it via acting or narration), you need to have an understanding of, if not who they are, at least their superficial mannerisms. Things that would jump out to the people who interact with this character (which reminds of the 7-3-1 technique:
https://www.gauntlet-rpg.com/blog/the-7-3-1-technique)
As an example, when I run
High and Dry I usually make the clerk at the Walston starport be a teen who's clearly bored out of their minds. So when I 'act' him out, I describe him as resting his chin on his hand, looking at the players through half-shut eyes, and getting progressively more annoyed and curt in his answers the longer they linger around the starport customs pestering him.
I think that for coming up with stuff like this, people-watching is a treasure trove. Sitting down at a park or a restaurant or public transportation and just observing the behaviours and tics and faces of the people around you, especially those that jump to you as particularly characterful. It's one of the things they
do recommend you in theatre classes, because by observing others you increase your repertoire of mannerisms you can draw from.
The next layer down starts to get more involved, and starts delving into actual psychology. This isn't really practical to do on the fly for a minor NPC but it might be worthwhile to consider for more important or recurring NPCs the players would interact with a lot.
While there's a lot of...
bovine excrement surrounding it, the field of psychometrics can be fertile ground (pun intended) for creating NPCs because by its very nature it gives you levers you can play with to suit a given situation. The currently more accepted model for personalities in humans is what is called the
Big Five Personality Traits model, which measures personalities by placing them somewhere within five, continuous scales: Openness, Conscientiousness, Extraversion, Agreeableness, and Neuroticism.
Amusingly enough, despite it being less useful as an actual tool to measure the human psyche, simpler, arguably worse models like the '
16 Personalities' one are better tools to create NPCs with, because it provides you with 16 ready-made, extensively documented archetypes you can simply nab and use at your table – just read up on what the specific personality type you've assigned the character is and base your acting and descriptions on that! The same could be said for Jung's Archetypes, or any other psychometric system that embraces clear-cut, binary classifications instead of the real, messy multi-band spectra of human psychology.
Rather amusingly, it is precisely this 'discretisation' of these psychological traits that make them convenient and useable at a gaming table, much like Marc Miller pointed out that the genius of Gary Gaigax was the 'digitisation' of attributes. Wish I could remember which interview he said that in...
Anyway, a bit of an incongruent, slightly haemorrhagic thought stream on the matter. Hopefully
something in it is of use lol