A common weakness is jumping to conclusions, then ignoring any contrary evidence. Virtually everyone does it, not just when playing cards, but all the time. It’s just a natural human weakness. For example, researchers have found that psychiatrists very quickly assign patients to a diagnostic category such as manic-depressive, then ignore any evidence that contradicts their diagnosis.

If psychiatrists, who should certainly know better, can make this mistake, just about anyone can. I have done it countless times. I put someone on a high pair or a flush draw, then discount or even ignore other possibilities and I do not change my mind when later streets provide more information. This sort of thinking has cost me lots of money over the years and still continues to do so.

This tendency is particularly important when reading hands: “Do not put undue emphasis on your opinion of your opponent’s hand. I know many players who put someone on a certain hand and play the rest of the hand assuming he has that hand. Great players are the ones who know how to constantly reevaluate their assumptions as each hand unfolds. They think deeply at each step and try to see if their initial idea is correct or if they have to modify it.

This is taking the method of reading hands too far. Instead you must put a player on a few different possible hands with varying degrees of probability for each of these hands. This is called a range and as the hand progresses you can normally narrow that range given the new clues.

The specific techniques for making these judgments are covered in a number of newer books. Newer because 5 or 10 years ago poker writers did not elaborate much on these hand ranges. Now I am just trying to make you aware of how natural it is to fall into this trap. It is not natural to think of many possibilities. It is much more natural to put someone on a hand, then have the courage of your convictions. But, if you want to read cards accurately, you must continuously fight this human, but destructive way of thinking.