Still going through the data but some first really interesting findings have emerged.
So, there were a total of 319 people who completed the survey and passed the attention checks. Average age of 39, mostly male. All recruited via various TTRPG forums like this.
To the question: "Imagine your player-character was aided an important way by another player-character. Would you feel grateful to the real person playing the character?"
75% said yes. Overwhelming majority. 11% said no, and 15% not sure.
To the question: "Imagine your player-character was promised something important by another player-character. However, your player-character was betrayed by the other player-character. Would you feel angry with the real person playing the character?"
Now 62% said NO. Only 17% said yes, with the rest unsure.
I mentioned this finding to Jon Peterson (RPG historian) and he thought this might reflect gamers' desire not to take other players' harmful actions against their characters personally. I thought it could mean that players might be surprised (pleasantly) when other players do them a good turn, but expect the opposite.
Another interesting but perhaps less surprising finding was that older age correlated negatively with power gaming (maximising rules to one's advantage) and positively with a greater emphasis on realistic simulation in gaming.
Thank you all for your help! Will post more as it's analysed.