Slide 15
Slide 15 text
Andrew Hinton | @inkblurt
We perceive environment as “nested,”
not in logical hierarchy.
We perceive elements in the
environment as invariant (persistent) or
variant (in flux). Invariance grounds our
experience (literally).
Invariance
Nestedness
Two of Gibson’s principles of
environmental perception.
Gibson created a marvelous system of principles and components that work as building
blocks for how we perceive our environment and its affordances. I can only barely touch on
them here, but I’ll mention a few important ones.
>> Invariance is the property of environmental structure that makes some of it persistent
over time, so that we can make sense of the whole. Terrestrial animals like us evolved on
stable ground, under a persistent sky. Substances and surfaces that persist allow us to learn
what properties they have, and what they afford us. This can be a useful idea in digital design
because in software, even though we can make everything fluid and variant, we need to
design invariant structures that ground the experience.
>> Nestedness: we perceive the environment as structures that relate to one another as
nested -- a stream is in a valley, which is between mountains, which are part of a range,
which are between earth and sky. There aren’t always definite boundaries, though, and this
isn’t a purely logical relationship -- there are overlaps and redundancies, and shifts in
meaning. A stick on the ground can be kindling or a club, or it can be part of a roof over our
heads in a shelter. It’s not just one defined thing in how it relates to the rest of the
environment.
This is a powerful idea when we look at something like faceted navigation, where the
meaning of a piece of content or an object shifts depending on what perspective a user is
bringing to it.