The Black Cats have aspirations towards becoming an established Premier League side after yo-yoing between the top flight and the Championship in the past.
Bruce, who arrived from Wigan in the summer, has been well backed in the transfer market by Sunderland owner Ellis Short as the club strive to achieve that aim.
But, after suggestions of a mini crisis having lost at Birmingham before a Carling Cup elimination at the hands of Aston Villa, Bruce insists changes will take time.
He said: "As I said when I walked through the door here, I have got to change the whole mental attitude of this club.
Change personnel"Over the last however-many years it has been up and down and we've got to try to change that if we can. We've got to try to copy the likes of Aston Villa and Everton, who have been there repeatedly in the Premier League and in and around the top 10 for years.
"To do that you have to have a certain mentality and it was probably typical of this club over the last few years to play so well against Manchester United and Liverpool then go to Birmingham and don't show up.
"That's what we've got to change and get that level of consistency where that sort of performance is not acceptable.
"To do that we change slightly. I can do one of two things; I can change the formation or I can change the personnel.
"Make no mistake, if I get another performance like that then I won't put up with it. It's as simple as that. I've told the players that I can't accept it if we go and not put a shift in like against Birmingham."