The reverse hierarchy theory (Hochstein and Ahissar, 2002) makes strong, but so far
untested, predictions on conscious vision. In this theory, local details encoded in
lower-order visual areas are unconsciously processed before being automatically and
rapidly combined into global information in higher-order visual areas, where conscious
percepts emerge. Contingent on current goals, local details can afterward be consciously
retrieved. This model therefore predicts that (1) global information is perceived
faster than local details, (2) global information is computed regardless of task demands
during early visual processing, and (3) spontaneous vision is dominated by global
percepts. We designed novel textured stimuli that are, as opposed to the classic Navon's
letters, truly hierarchical (i.e., where global information is solely defined by local
information but where local and global orientations can still be manipulated separately).
In line with the predictions, observers were systematically faster reporting global
than local properties of those stimuli. Second, global information could be decoded
from magneto-encephalographic data during early visual processing regardless of task
demands. Last, spontaneous subjective reports were dominated by global information
and the frequency and speed of spontaneous global perception correlated with the accuracy
and speed in the global task. No such correlation was observed for local information.
We therefore show that information at different levels of the visual hierarchy is
not equally likely to become conscious; rather, conscious percepts emerge preferentially
at a global level. We further show that spontaneous reports can be reliable and are
tightly linked to objective performance at the global level.