Finding your orientation and the perceptual upright in (and
off) this crazy mixed up world.
What's up? The orientation in which we expect
polarized objects to be ('upright')? Or the perceived direction
of gravity? We
could choose either depending on the situation and the instructions.
These directions turn out not necessarily to be aligned although
both depend on visual cues, the orientation of your body (where
your head is) and gravity. In this talk I will describe how we
can measure these directions and how these cues are combined
to produce them - it turns out not to be entirely predicable
from the reliability of the cues. I will then dissect, using
the flexibility of virtual reality, the visual cues we use to
identify the roles of the structure (the walls, floor and ceiling
- low spatial frequencies - dorsal pathways) and the contents
(objects and furniture within the environment - high spatial
frequencies - ventral pathways). And by the way, what's the 'floor'
anyway? What is the contribution of the room's structural features
and the orientations of gravity and the body to the perception
of which surface this is? These sorts of questions are particularly
germane in ambiguous environments when one or more of the cues
are taken away. In space no-one can hear you scream.