The Use of Iambic Pentameter in the

lightness similarity and responses were recorded. The critical central column of circles
was manipulated by depicting a tinted transparency in front of it. As a result, the central
circles matched the pre-constancy lightness of the two columns on one side of the
stimulus. If participants grouped the central circles by similarity of pre-constancy
lightness, then they would group it with this side of columns. In Figure 16A for example,
the central column of circles matches the pre-constancy lightness of the circles on the left
hand side. However, after the transparency has been accounted for, the actual post-
constancy lightness of the central circles can be seen. The post-constancy lightness of the
central circles matched the opposing two columns of circles in each stimulus. If
participants grouped the central circles by similarity of post- constancy lightness, they
would group it with these opposing columns. In Figure 16A for example, the post-
constancy lightness of the central circles matches the circles in the columns on the right
hand side.
Figure 16. Ambiguous achromatic color grouping stimuli and results
A
Note. (a) Experimental stimulus, Schulz (2001). Central circles match pre-constancy lightness of columns on left and
post-constancy lightness of columns on right. (b) Mean percent of grouping by post-constancy lightness across time.
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B