{Reference Type}: Journal Article {Title}: An evaluation of the Ultimatum Game as a measure of irritability and anger. {Author}: Gröndal M;Ask K;Winblad S; {Journal}: PLoS One {Volume}: 19 {Issue}: 8 {Year}: 2024 {Factor}: 3.752 {DOI}: 10.1371/journal.pone.0304038 {Abstract}: The Ultimatum Game is an effective tool for understanding how social decision-making is influenced by emotions in both research and clinical settings. Previous findings have shown that the Ultimatum Game can evoke negative emotions, especially anger and aggression. In a sample of non-clinical adults (N = 143) we evaluated the sensitivity of an anger-infused version of the Ultimatum Game to individual differences in anger and irritability. Findings showed significant relationships between anger and aggressive behaviors in the Ultimatum game, but no association between irritability and aggressive behavior were observed. This indicates that the anger-infused Ultimatum Game is a promising method for studying individual differences in trait anger and anger expression. However, the relationship between decision-making in the anger-infused Ultimatum Game and irritability is less straight forward and needs further investigation. Therefore, when studying the behavioral responses of irritability, it would be beneficial to capture other behaviors beyond aggressive responses.