are first impressions reversible?

just remember to wear pants next time.

i have changed my mind about a person

I have too, and people have changed their minds about me (both for better and for worse).

What about impressions you get of people online?

i agree - i have totally changed my opinions of people from my first impression, and i think vice versa for me. i reckon an online impression would be harder to change. i think sometimes you have to actively reform people's impressions, so it's an interactive process - which might be harder to achieve online? not sure why though. i'm not articulating this well am i.

See, online, I have changed my impression of people without them trying to change as far as I can tell, I just notice things over time that I didn't notice at first which makes me appreciate them more (or, more often, irritates fuck out of me).

I suppose that happens in real life too, but it's more magnified on the internet, somehow.

maybe it means that your first impression is more limited online and therefore less permanent?

maybe superficial more than 'limited'

forgetting online impressions for a sec, this - "i think sometimes you have to actively reform people's impressions, so it's an interactive process" is quite accurate i think. but it can be a bit harder in some situations where there isnt enough time to 'remedy' the initial impression.

for instance, i recent joined a book club and dont think i really gave the best impression of myself in the first one, but it seems harder to break that for some reason, most likely cos im not really gelling with some of the other members. but actively reforming someones impressions of you might be a pointless exercise i think. not everyone is going to like you and vice versa.

yep this is true, and on the whole i would only be bothered if i gave the wrong impression to certain people - like people i have to work with a lot or someone i fancy etc etc

i just get botherered about not giving a good FI if i think i wasnt really being myself.

sure, me too. but sometimes, as you say, first impressions are a product of circumstance - time, situation etc - so i think whether you're being yourself or not might not have that much to do with someone getting a bad impression of you. in which case 'giving' a bad impression is perhaps a poor description.

actually i think i tell a lie about only being bothered sometimes - i think i worry about this a lot. i'm really shy with new people, i can never think of anything to say, and i think people almost invariably interpret this as me being aloof or up myself or something. this happened to me today in fact - someone i know by sight came and introduced himself to me (what a nice thing to do) and i think i made a prat of myself, as though i answered all of his questions i didn't reciprocate with any of my own. i've been worried about it all arvo.

I don't consciously attempt to set a shining first impression, but IRL at least I usually do quite well (I'm not, of course, the best judge of this; Matt or Ed or Tissp or indeed Andrew Farrell could probably answer this one a little better, although I was horrendously sleep-deprived and near-hallucinatory when I met them). I'm normally quite quick to break the ice, sense where the conversation's headed, and provide interesting fodder for discussion. Online, this confidence, alas, translates directly into TMI and apparent over-enthusiasm, which explains the ongoing flame-war some have chosen to foister upon me. My style works far better in person.

All egoism aside, the answer to the original question I believe to be 'yes', but only if a) an effort is made on the part of the judger to change their own interpretations of the other's consistent actions, or b) a chance (it must be chance) occurrence involving both parties brings out a different side in one or both of them.

Impressions I get of people online tend to be more mutable than IRL impressions, because I know so much less about people over an electronic interface. Five minutes with a single one of you ILXors, for instance, would probably reveal more (mutually) than my 7 months on this site. I'd like to think I have a rough idea about some of you, but physical and aural communication says SO much more than typed (or jpg'd) missives. This is why I'm so indignant when people directly judge me; they're mostly talking out of their (prejudiced) arses.

Another way in which one can change one's opinion is when the chance occurrence fades and you drift away from its fallout, opinion settling back to a more rational level some time afterwards. Normally this works in favour of 'disowning' a 'friend' you'd been thrown in with but in retrospect wasn't a particularly nice/interesting person anyway.