Surprise is predicted by event probability, outcome valence, outcome meaningfulness, and gender

The present research was designed to better understand how the magnitude of experienced surprise is affected by both individual difference variables as well as variations in surprise-eliciting stimuli. Eighty-five participants played 5 versions of a slot machine-like game. The five games only differed with respect to the probability of winning each trial—10 % (i.e., wins were highly unusual), 30, 50, 70, and 90 % (i.e., losses were highly unusual). Players were given a fictitious “bankroll” at the beginning of each game and played up to 25 trials of each game. On each trial, players selected their wager amount, “pulled” the handle, learned the outcome (win or loss), and reported their surprise level using a 1 (none) to 9 (extremely) Likert scale. Replicating past research, results revealed that self-reported surprise was inversely related to outcome probability and that wins were rated as more surprising than losses, even when wins and losses occurred at the same level of probability. Novel results include finding that larger wagers predicted greater felt surprise (regardless of outcome), and that women reported greater surprise to both wins and losses than men.