Abstract: In smart spaces with connected smart lighting, there is an opportunity to deliver smartphone notifications using peripheral light, along with using standard smartphone modalities such as sound, vibration and LEDs, in order to help a user perceive them without constantly monitoring their mobile device. In this paper, we examine the effectiveness of on-device and extra-device modalities through smart lighting. We address a gap in literature by establishing a foundation that explains the role of modalities with which a notification is delivered on a mobile device. For this purpose, we conducted two ecologically valid and carefully designed experiments in a controlled environment that simulates multitasking in a smart home environment, and demonstrate that modality preferences are dependent on the environment context, by analysing subjective user data through a machine learning approach. We derive a set of guidelines for choosing notification modalities and set future research directions.