A continuous, real-time, self-rating system of affective states using a joystick has been devised. This study investigated if the process of real-time rating interfered with the participants' affective state. Participants watched a video clip that induced either positive or negative emotions, with or without real-time affect estimation. The emotions that were induced were measured using the word association task (rate of positive words), facial electromyography (integrated activities), electrocardiography (heart rate), and a questionnaire (visual analogue scales). Results indicated that there were no significant differences in induced emotions between the two conditions. It is concluded that using a joystick to assess real-time affect does not interfere with the emotions of the participants.