How Confidence Affects Blackjack Strategy


Blackjack is a game of cards where players attempt to beat the dealer. The objective of the game is to achieve a hand value of 21 or as close to it as possible. The player is dealt two cards and has the option to request more based on a set of rules. A player can choose to stand (stop drawing cards) or draw (request more cards) depending on a combination of the cards and dealer’s face up card, which determines whether the dealer is likely to bust.

The game is played on a semicircular table and can accommodate between two and seven players. The dealer stands behind the table and chip rack.

Traditionally, the player and dealer have two hands each. The player’s hand can contain any number of cards and may be a mixture of suits, including tens, spades, hearts and diamonds. A blackjack is a hand that contains an Ace and a ten-valued card. The dealer’s hand must be a King, Queen or Jack of spades and must have an Ace or a 10. A player can also split pairs of cards, but the dealer cannot. A split pair can be a good play if the dealer shows a 10, an Ace, or a five.

While the basic rules of the game are fairly simple, there are a large number of variants of the game. These variations are mainly determined by the house rules and the number of decks used. Some casinos offer a single deck, while others use 6, 8, or 12 decks. A key difference is that some casinos require the dealer to stand on a soft 17, while others mandate that they hit.

In the study described below, we manipulated participants’ confidence in their ability to make the correct play in blackjack and examined how this unjustified confidence affected psychological and behavioral consequences. These included positive outcome expectations, state anxiety, and risk taking. Specifically, we expected that higher levels of unjustified confidence would result in increased optimism about the likelihood of winning and lower levels of state anxiety. Additionally, we predicted that unjustified confidence would lead to larger bets and fewer uses of hints designed to improve playing performance.

Results supported these hypotheses. In the first experiment, participants who were more confident in their knowledge of blackjack strategy reported higher positive outcome expectations and less state anxiety than those who were more skeptical about their abilities. In addition, participants who were more confident in their ability to play blackjack correctly exhibited less information search and consideration and took greater risks than those who were more doubtful of their skills.

The second experiment examined the effect of unjustified confidence on the same psychological and behavioral outcomes, except that we measured confidence after participants had played a random amount of rounds of blackjack. We also manipulated the number of rounds that each participant was expected to play, so that participants who were more confident in their ability to win had to bet more than those who were less confident.