Researchers interested in factors that influence people's performance identified an interaction effect between stress level and the difficulty of the task. performance on easy tasks was relatively better under high stress than under low stress; performance on difficult tasks was relatively better under low stress than under high stress. the researchers further found that the interaction effect of stress and difficulty was more pronounced for men than for women. the combined effect of the stress, difficulty, and gender independent variables represents . triple or three-way interaction effect. b. simple main effect. c. modified main effect. d. ceiling (men) and floor (women) effect.