The Use of Iambic Pentameter in the

As shown in Figure 16B, for the lightness similarity experiment, grouping was
based primarily on pre-constancy lightness at the shorter exposure time (80.5% pre-
constancy, 19.5 post-constancy at 200ms). At the longest exposure time, however, pre-
constancy grouping decreased and there was an increase in post-constancy grouping
(38% pre-constancy, 62% post-constancy at 2000ms). These results show that grouping
can begin by pre-constancy lightness and then switch to occur by post-constancy
lightness when exposure time is increased.
Grouping by shape similarity. In a second experiment by Schulz and Sanocki
(2001), ambiguous shape stimuli were presented for 200 or 2000ms. Experimental
stimuli (Figure 17A) followed shape completion stimuli used in prior research (Palmer,
Neff & Beck, 1996). Stimuli contained 5 columns of shapes. Participants were asked to
group the central column of shapes with the columns on the right or left hand side by
similarity and responses were recorded. Two of the outer columns on each experimental
stimulus were composed of half circles. The opposing two outer columns were composed
of full circles. The critical central column was composed of circles. However, the central
column was manipulated by an opaque strip that was depicted to be in front of it. As a
result, the incomplete shape of the central circles appeared to match the shape of the two
columns of incomplete circles on one side of the stimulus. If participants grouped the
central circles by similarity of incomplete shape, then they would group the central
circles with this side of columns. In Figure 17A, for example, the central circles match
the incomplete shape of the circles on the left. However, after the opaque strip is
accounted for, the complete shape of the central circles should be perceived. This
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