In any reversible figure-
ground pattern, say one 
composed of a black region and 
a white region, which region 
any given observer will first 
perceive as figure may be 
largely a matter of chance, 
particularly if adjoining black 
and white regions are 
surrounded by gray rather than 
presented on a white screen. 
The black region is then not 
strongly favored because it 
contrasts more with the white 
of the screen than does the 
white region. However, other 
factors may also influence our 
perception of a particular 
region as figure. We tend to 
perceive as figure those regions 
that are surrounded or smaller, 
symmetrical, and vertical or 
horizontal. It can now be 
understood why, in viewing the 
map of Europe, we at first 
organize the pattern into black 
figural regions and why, given 
the fact that these regions are 
novel shapes and given the lack 
of perception of a shape that 
corresponds to the continent of 
Europe, we initially do not 
recognize anything.