The following is a piece I, Zach Elwood, wrote in 2014 or so. It was written for a poker site that went out of business, so I decided to reshare this in 2026.
How people act when playing poker is different from how they act during other activities. I have seen quite a few self-described “behavior experts” try to apply their general knowledge to poker. Unless these experts have played a lot of poker, they are doomed to make mistakes. Poker is a unique environment, with unique situations.
Sure, some knowledge will cross over between criminal interrogations and poker playing. There are some similarities in human behavior across pretty much every activity. But there are also many differences in these two areas. There are many ways that a good understanding of general human behavior can fail at the poker table.
I will use examples from the poker tells book Read ‘Em And Reap (written by Joe Navarro and Marvin Karlins, presented by Phil Hellmuth) because I think that book contains some of the most common misconceptions that result from trying to apply general behavioral knowledge to poker players.
Poker is Not a Criminal Interrogation
Let’s start with the misconception that a criminal interrogation has much in common with a poker game. You might think that a bluffer might be similar to a guilty criminal who is being investigated. Both are doing something they are trying to get away with; both are trying to deceive.
But here’s the main difference: a person being interrogated, whether innocent or guilty, does not mind appearing nervous, scared, or unconfident. In fact, it may be to a guilty person’s benefit to appear all of these things, to better appear innocent. Whereas a poker player who is bluffing has an instinctual urge to not want to appear nervous, scared, or unconfident. A bluffer, or even just someone with a vulnerable hand, does not want to display behavior that may make others perceive him as vulnerable or weak.
That is the main difference, and it is a big one. Someone experienced in interrogating and interviewing people might assume that human feelings appear similarly in poker as they do in the interrogation room. But poker is its own particular environment with its own rules.
Let’s look at a few examples from Read ‘Em and Reap where this basic misunderstanding crops up.
Are Pressed Lips a Poker Tell?
Navarro states that lips pressed tight together indicate a person under stress, as does biting the lip. While this is generally true for most non-poker situations, in poker you are rarely going to see someone making their discomfort known in such a way, and you are especially unlikely to find a bluffer doing this.
In fact, in my book Reading Poker Tells I listed pressed-together lips as an indicator of a strong hand. Many players with strong hands instinctually try to look weak; pressing lips together is one way to do this. Biting lips is another.
These are related to other (mostly unconscious) ways that players with strong hands try to look vulnerable, like slumping in the seat, emitting Mike Caro’s so-called “poker clack” (the tsk-tsk, “too bad” sound), or shaking the head slightly.
While you might occasionally see pressed lips or lip-biting exhibited truthfully, it will usually be in situations where it doesn’t matter much, such as when a player looks down at their hole cards pre-flop and then folds, or when a player is facing a last bet where they’re just debating between calling or folding.
Is Biting Nails a Poker Tell?
Poker is not an interrogation.
Navarro points out that biting nails is indicative of stress and that it means “a weak to mediocre hand.” Again, while this is generally true for non-poker situations, you will be unlikely to see a person involved in a serious pot, whether bluffing or just vulnerable, bite their nails. As with the pressed lips and the biting of lips, most people are generally aware that biting your nails is indicative of stress, so why would someone with a vulnerable hand do it?
Is Pacifying Behavior a Sign of Weakness?
Navarro lists a few “pacifying behaviors” that are indicators of a person experiencing stress. These self-soothing behaviors include:
- Rubbing the neck
- Rubbing the forehead
- Exhaling through puffed cheeks
- Stroking the face
- Pulling the earlobe
- Whistling
- Neck ventilation (including adjusting a neck tie)
As with the previous behaviors, it’s easy to imagine a nervous criminal being interrogated doing these things in order to calm himself but it’s very hard to find a stressed poker player, especially a bluffer, doing these things. This is just because these behaviors are so well-known as signs of distress so poker players with even the slightest experience will instinctively avoid engaging in them when they hold weak hands. In fact the opposite is true; players with strong hands will be more likely to engage in behaviors that are associated with nervousness or disappointment.
Competitive Games Are Unique Environments
It’s possible that in very low stakes games, and with very beginner-level poker players, the nervous and self-soothing behaviors listed above might be exhibited truthfully. But at most stakes, and with even slightly experienced players, you will be unlikely to witness those behaviors from players with weak hands.
I’m very confident that if you scour the many thousands of hours of televised poker available online you will virtually never find these behaviors from a bluffer — or even from a player who is vulnerable in the middle of a hand.
I think Navarro’s misconceptions of general poker behavior are a good example of what happens when someone with a decent level of behavioral expertise tries to “cross over” his knowledge to the poker world. It was probably assumed that his experiences as an FBI agent would enable Navarro to produce the definitive book on poker behavior. But the few points I’ve brought up here are good supporting arguments for the idea that the poker table is a unique environment, with its own behavioral pressure points, and it defies the application of general behavioral knowledge.
Want to read about the creation of this book? Check out a talk I had with the co-author of Read ‘Em and Reap.