The Roos have led in three of their five game this season in the last quarter, before being overrun.
Harvey told RSN Breakfast on Friday the leaders at the club go into their shell when games get tight.
“I look at our leadership group and I think we’ve got fantastic leaders,” Harvey said.
“But under the pressure, when you’re on the field, I think you can go back into your shell and I think some of our leaders do do that, especially when you’re tired and you’re not thinking straight.
“The thing that I’m seeing — and it happened a little bit last year as well — we play free football. Kangaroos play free footy and they go quite well.
“Then just as the game gets a little tighter, old habits (creep in). They kick the ball down the line, they take the 45, they don’t go on after the handball receive.
“They go back into their shell. And that’s when teams will get a run on.”
North’s record under coach Brad Scott has been well publicised, with the side winning just four of 19 games decided by less than six points under his tenure.
Yet another close loss last week after being in a winnable position, has led to the axing of club veterans Lindsay Thomas and Andrew Swallow, who prior to this season, had captained the club for five years.
The decision to drop Swallow has left Harvey somewhat perplexed.
“I think Lindsay has been struggling. He’s a small forward that hasn’t been kicking goals so that makes it tough to stay in the team,” Harvey said.
“Swallow is an interesting one for me. He’s a little bit slower. He’s slowed down since his achilles problem. If they don’t play him in the guts, I don’t think you can hide him down back or hide him up forward.
“To drop Lindsay and drop Andrew, I think, sends a message to everyone that you’re on standby. If you don’t perform how we want you to play, you’ll go out of the team.”
The Kanagroos face the Gold Coast Suns at Etihad Stadium on Saturday night.