The Semiotics of Embodied Interaction… Variance and Invariance

O’Neill, S. (2008) Interactive Media: The Semiotics of Embodied Interaction. London: Springer-Verlag.

“In Gibson’s view of perception, an active perceiver picks up and distinguishes between variant and invariant information. Either of these may be information about the perceiver or the environment but the distinction between the variant and invariant builds to create an awareness of the perceiver’s place within that environment.” (p61)

Annotation
The relationship between ourselves in the world, and the environment that surrounds us at any one time, is an important perceptual one. The environment is always perceptively relative to the person in that environment. They are aware that if they move, spatially and temporally that environment persistently envelope them. The perceptual changes within that environment are what guide and suggest options. These perceptual changes can be described as variant and invariant. In other words, some information within the environment stays constant and some will vary allowing behaviour change to be enacted. To give a simple example of variance and invariance it may be useful to look at an interactive experience on a computer. During any interaction the keyboard, screen and device will always be there (invariant) despite what is happening on the screen or whatever input device is being used (variant). The changes perceived between what is in the environment (keyboard, screen, device, table, room etc.) and what is changing within that environment is directly attributed to the user’s sense of being in the interaction. Whether this experience can be described as an aesthetic or an anaesthetic experience is another matter. What is important is the distinction between the two states and how this helps the conscious and subconscious directly as embodied knowledge perceive what is happening and can happen next.