Abstract
Cataliotti and Gilchrist (1995) reported that the lightness of a black square in a luminance staircase was not altered by moving the position of a white square from a remote to an adjacent location. They argued that this result supported an anchoring model of lightness as opposed to a local contrast explanation. Economou, Zdravkovic and Gilchrist (2007) tested two more predictions of the anchoring model: 1) that the strength of simultaneous brightness contrast (SBC) should increase for darker targets and 2) that in a staircase SBC display only the decremental targets should appear to differ from one another. Economou et al. (2007) reported evidence to support both of these predictions and argued that contrast models and the ODOG model in particular could not account for these effects. The present study examined the matching behavior of subjects using stimuli similar to those in the aforementioned studies. The brightness of each of the five steps composing a luminance staircase (4–120 cd/m2) was measured for both a sequential staircase and for a disrupted staircase. Measurements were obtained for staircases surrounded by three different background luminances (5, 62 and 119 cd/m2). In a second experiment background luminance was held constant (62 cd/m2) and identical test patches were added to the centers of each step of the sequential staircase to produce a staircase SBC stimulus. The brightness of each of the test patches was measured for three test patch luminances: 24, 62 and 100 cd/m2. The matching data are compared directly to the predictions of the anchoring model (Gilchrist et al., 1999; Gilchrist, 2006) and the multiscale filtering model (the ODOG model) of Blakeslee and McCourt (1999).
This work was supported by grants from the National Science Foundation (IBN-0212789), the National Eye Institute (NEI) (R01 EY014015) and the National Center for Research Resources (NCRR) (P20 RR020151).