the purpose of this study was twofold: to examine the effects of task difficulty and the type a behavior pattern on the inverted-u relationship between stress level (arousal) and performance, and to examine possible type a/b differences in response to competition. a 2 x 2 factorial design was used in this study. the two factors were the type of task (simple or complex) and the behavior pattern of the subject (type a or type b)* subjects were 60 males from introductory psychology classes at 阿根廷vs墨西哥竞猜 . three male confederates were employed to act as competitors against experimental subjects. subjects practiced either a simple (digit letter) task or a complex (colour letter) task for seven trials, and then competed against a confederate on the eighth trial. tonic heart rate was recorded throughout the study as a physiological measure of stress, pleasantness ratings were obtained as a cognitive, evaluative measure of stress, and performance on the task was recorded as a behavioral measure of stress.