Researchers have shown that such parts do, in fact, play a role in object rec-
ognition. They have done so by presenting subjects with degraded pictures of
objects that either do or do not leave parts intact (Biederman, 1987; Biederman
& Cooper, 1991). The first column of figure 7.38 shows line drawings of com-
mon objects. The middle column shows those same objects with only informa-
tion deleted that still allows you to detect what the parts are and how they are
combined. The right-hand column presents deletions that disrupt the identities
of and relationships between the parts. Do you agree that it would be hard for
you to recognize some of these objects based just on the drawings in the third
column? The contrast here suggests that you can recognize objects with limited
information (just as you can restore missing phonemes), but not if that infor-
mation disrupts the critical parts.
Figure 7.37
Recognition by components. Suggested components of 3-dimensional objects and examples of how
they may combine. In the top half of the figure, each 3-D object is constructed of cylinders of dif-
ferent sizes. In the bottom half of the figure, several different building blocks are combined to form
familiar objects.
Perception 179