Figure 7. Error distributions reveal evidence for center-surround chunking.

A-C) Signed color reproduction errors made in the random spacing condition by (A) subjects, (B) center-surround chunking models, and (C) independent encoding models. Data is collapsed across all simulated or actual sessions. D-F) Same as A-C but for the fixed spacing condition. Red dashed lines indicate probed and non-probed target locations. Note that the alignment of non-probed target locations emphasizes the prominence of non-probed target reports (binding errors), which would appear uniformly distributed in the random spacing condition. G-I) Difference in above error distributions for random minus fixed. To aid in visualization, bin count differences were smoothed with a Gaussian kernel (standard deviation = 1 bin). Subjects and the center-surround chunking model show increased moderately small, but non-zero, errors in the random spacing condition. Note that differences of reports between the random and fixed conditions near the non-probed targets are present in both models, as they simply reflect an artifact of the alignment of binding errors in the fixed spacing condition.