Unknowing
The audience is unknowing in the sense that they are not aware of context, content and interaction. This can differ in their general (intrinsic, explicit & tacit) knowledge and interests; how much they are aware of certain spectacles. As a designer you can still design things in a way that won’t connect to the audiences general knowledge at first sight. By not giving away a lot of information beforehand through content, visual design and interaction you can delay the audiences realization of what your narrative is about. This can be used to create elements of surprise, which can provide more engagement and stronger reactions.
Spectator
A spectator is someone who is presented with information in a linear path, as the designer intended. The content doesn’t necessarily have a linear narrative, but the way in which it’s presented in does. The spectator doesn’t interact with what’s presented in front of them, what is presented is exactly the same for every spectator. The difference in how it’s perceived by the spectator relies solely on their general (intrinsic, explicit & tacit) knowledge, interests and their choice of how they spectate (duration, position, attention, etc.).