yeah id say there's a psychological factor that comes into play unconsciously when we select clothes i reckon. BUT... this isn't the case for everyone. a lot of people will make a judgment based on appearance only to realise their personality is completely unexpected.
No, I think it gives us a misconstrued idea of what their personality is like based up societal standards. I've met plenty of people that I've misjudged by their clothing. I thought they'd have one type of personality but they usually had the total opposite.