Nicklaus and his son Jackie studied the line, and seemed to have made up their collective mind. But Nicklaus saw something at the last minute. He remembered having a similar putt years ago in the Masters, and that it broke slightly differently than he was seeing. I've found that trust in one's self at key moments is a common trait among great champions. Extreme moments, of course, produce extreme reactions, and not only from the golfers who hit the shots.
Golf is a game of long pauses and bursts of activity.
Spectators react as they follow the end of a shot, and see where it stops. I think about the last green of the 1977 British Open at Turnberry, where Nicklaus, a shot behind Tom Watson, played from beside a gorse bush. Watson had hit a 7-iron from the fairway to within three feet of the hole. Nicklaus' only chance was to get the ball on the green and hole his putt, which would force Watson to make his. Nicklaus, being Nicklaus, smashed at the ball and it came out cleanly, stopping 30 feet from the hole.