Total irradiance and predicted visual contrasts between food pellets and background distracters under experimental illumination modeled assuming either bright or dim (photon-noise limited) conditions.

a>1 jnd difference between lighting conditions (p<0.001) for both vision models.
b>1 jnd difference between lighting conditions (p = 0.007) for bright vision model only.
c>1 jnd difference between food/distracter contrast and distracter/distracter contrast (p<0.001) in both vision models.