Although this theory runs 
contrary to the common 
impression that we effortlessly 
see a red triangle as a unified 
object, contemporary brain 
research supports the 
"separability"hypothesis. 
Increasingly in recent years 
brain researchers, such as 
Semir Zeki in England and 
Charles Gross at Princeton, 
have uncovered perceptual 
regions in the visual cortex 
that seem to process only a 
single feature, so that we might 
justifiably refer to separate 
neural processing centers for 
color, motion, orientation, and 
the like. Thus it might be 
correct to suggest, as Treisman 
once did, that attention is the 
"glue" that binds the features 
of an object together and that 
without this attentional "glue" 
the features might well be 
detected but would be "free 
floating" and not "attached" to 
a specific object in a specific 
place.

    In 1982 Anne Treisman and 
Hillary Schmidt made a 
dramatic discovery that 
directly supported this 
theoretical view. Subjects in an 
experiment were shown 
simultaneously several items, 
each a geometrical shape of a 
given color. When the display 
was presented very briefly, 
usually under the guise of some 
other task, subjects often 
reported seeing colored shapes 
that were not presented on that 
trial. The shape and the color 
perceived were both present in 
the display, but the two were 
not conjoined in any figure 
presented. They were what the 
investigators called “illusory 
conjunctions.”