Psychometric function for one observer (SH) for trials that used a reference probe with a fixed Michelson contrast of 0.6. In this block of trials the plaid AB was adapted in the right visual hemi-field while the components were adapted on the left. For the component probe the PSE occurs when the probes are genuinely similar, consistent with the roughly equal component adaptation in both visual hemi-fields. For the plaid probe, however, the PSE occurs when the right-hand probe has a contrast of 0.76 versus 0.6 in the left, indicating that the plaid was more strongly adapted by the compound pattern adaptor. Note that, although for this subject there was a difference in the slopes of the psychometric function between component probes, this was not generally the case.