Speaking at a sponsorship function he said concepts like expectation, pressure and momentum could not be identified on white boards nor incorporated into plans.
"Even if you acknowledge them, say them, it is the hardest thing to explain. Ireland have talked about not playing well when they have this burden. It is the hardest thing to deal with," he said.
All Blacks coach Steve Hansen several times said when Ireland reached the No1 ranking in the world that how they handled that pressure would be interesting.
Johnson added: "[In Japan] I was talking to one of the All Blacks lads, an experienced player who played in the 2011 final against France.
"No one gave France a chance and they could have won it. He told me the All Blacks were under so much pressure they could hardly breathe, could barely play.
"The lessons for England will be the psychology of it. Playing as an underdog frees you up a bit, it is just a natural reaction when people say you are rubbish.
"That's what the Boks had all week. People were saying they were going to get pounded. I was like 'woah'. We are talking about a proud, proud rugby nation in just the same way New Zealand are. In the history of the game those two nations are the top dogs. They are big and physical, they were going to come out fired up as underdogs do," he said.
Johnson said playing with something to lose alters the psychology of the challenge. It had happened in the 2015 World Cup group game when England had gone to halftime leading by six against Wales.
"When you are losing it focuses you. You don't really talk about being up. What are we going to do at halftime if we are leading by 12 points never gets talked about. But what happens is you defend the lead. It is very difficult not to do what they did and England got beat," he said.
That was similar to the situation England found themselves in the Cup final.
"Last week England were defending a Cup everyone had given them and the South Africans were fired up by everyone telling them how good this lot were. They had the psyche right.
"They came out and put England under huge pressure. England could never wrestle it back just as the Kiwis couldn't against us. When you are out there in that blizzard, caught in the maelstrom, the physicality and intensity, it's not easy to turn it around," Johnson said.
With their win over the All Blacks, England were suddenly facing the burden of expectation in the final and had capitulated to it.
"It's tough when it happens to you. Some of the boys will want to put it away and not think about it too much. It can take years to process what happened, to have the distance from it to properly work it out.
"The pressure at World Cups are like nothing else, they define the era. Some guys played in fantastic All Black teams and never won a World Cup," he said.
England would be disappointed with their loss. But it was only a game of rugby and he felt there would be better to come from England in the future.