Characterising mesopic spectral sensitivity from reaction times

• Published in: Vision research (Oxford) 2006-11, Vol.46 (25), p.4232-4243
• Main Authors: Walkey, H.C., Harlow, J.A., Barbur, J.L.
• Format: Article
• Language: English
• Subjects: Adaptation, Ocular; Adult; Biological and medical sciences; Chromatic pathways; Color Perception - physiology; Contrast Sensitivity - physiology; Eye and associated structures. Visual pathways and centers. Vision; Female; Fundamental and applied biological sciences. Psychology; Humans; Light; Male; Mathematics; Mesopic vision; Models, Psychological; Photic Stimulation - methods; Photometry; Psychophysics; Reaction Time; Sensory Thresholds; Spectral sensitivity; Vertebrates: nervous system and sense organs; Visual Perception - physiology
• ISSN: 0042-6989; 1878-5646
• DOI: 10.1016/j.visres.2006.08.002

The spectral sensitivity of the eye was investigated using reaction times to broadband chromatic stimuli over a range of background luminances. Relative sensitivity was determined from the nonlinear reaction time curve by converting reaction times to a linear measure that was independent of spectral sensitivity. Two models for mesopic spectral sensitivity were compared. The first was a linear combination of V ( λ) and V′ ( λ), and the second included input from the L-M colour-opponent mechanism and the S-cones. The second model produced a significantly better fit to the data. The chromatic mechanisms appear to contribute to reaction time when there is an appreciable chromatic signal but luminance contrast is low.