The processing of Navon figures (Navon, 1977), i.e.,
hierarchical letter stimuli, has been studied in experimental
settings for many years. In particular, they have been studied
in the context of visual hemifield studies and yielded an
interaction between hemifield and whether a target is at the
local or global level, with a right hemisphere advantage for
the global level, and a left hemisphere advantage for the
targets at the local level (Sergent, 1982). This is a ventral
stream process, however, and we were interested in whether
there might be a similar interaction for hierarchical motion
stimuli, presumably a dorsal stream process. Hence we
developed a series of dynamic geometric Navon figures in
order to study global/local rotation processing. These figures
consist of a global figure (a triangle or a square) made up of
local figures (also triangles or squares). Both global and local
figures can rotate in either clockwise or counterclockwise
directions independently. We found that there is no right or
left visual field perceptual advantage for either the global or
local levels of these figures. However, curiously enough, we
found that there is a significant processing advantage for
clockwise motion compared to counterclockwise motion. We
also found a highly significant interaction between the
detection of a particular rotational motion and the presence or
absence of that motion in the figure being examined. Finally,
our data strongly support the Global Precedence Hypothesis
which says that people generally tend to focus on the global
properties of an object before local properties and that
processing proceeds in a global-to-local direction.