Event-related potentials were recorded to investigate
the mechanisms of hierarchical processing and level-repetition
effect. Participants identified targets that appeared at
global, local, or both levels of hierarchical patterns.
Reaction times showed global precedence and level-repetition
effects. An occipital P1 wave was enhanced to local relative
to global targets. The P1 to local targets was also larger
when preceded by global than local targets. Global and
both-level target selections were indexed by two posterior
negativities peaking at 130 and 190 ms poststimulus, whereas
local target selection was indexed by a broad occipitotemporal
negativity. A late selection positivity was observed over
the left occipitotemporal site for global targets but over
the central site for local targets. The findings suggest
that sensory-perceptual mechanisms contribute to global
precedence and level-repetition effects in hierarchical
processing.