Take a gander at this cube. It will probably look weird because
your visual system can’t decide how to perceive it. This
persistent ambiguity is called visual rivalry, and in the case
of the Necker Cube, it results from spatial conflict, or when
two objects strike the same place in our retina. Most scientists
think visual rivalry requires spatial conflict, but the authors
of a recent Psychological Science study have shown that this
assumption is not necessarily true. Using non-retinal reference
frames, which are objects (e.g., mountains in the background)
that make the world appear stable even when our eyes are moving,
the study authors created a scenario in which visual rivalry
could occur without spatial conflict. They showed participants
different arrangements of four dots placed on three larger white
discs (the reference frames) that switched back and forth.
Depending on the scenario, the dots moved either with the discs
or in opposition to the discs. After viewing this “motion
quartet,” participants were