Abstract Measurement of an individual’s subjective experience of emotion has long been a key component of emotion research, but it presents some unique challenges. Researchers have developed a number of different methods to assess the subjective emotional experiences of study participants, each of which has its strengths and limitations. Self-report measures such as the Positive and Negative Affect Schedule (PANAS; Watson, Clark, & Tellegen, 1988) are well established and easy to complete and provide useful information; however, administration of any written measure necessitates an interruption in the flow of an experiment and does not allow frequent or continuous sampling of affective states. More involved methods, such as interviewing, give a detailed and comprehensive picture of a person’s emotions, but they are time-consuming and can provide only a retrospective report of affect. The interactive computer version of the Self-Assessment Manikin (SAM) Scales (Bradley & Lang, 1994) allows online assessment of both emotional valence and arousal levels, but it, too, does not provide a continuous record of affect.