Gowdy P D, Stromeyer C F, Kronauer R E
Department of Psychology, Harvard University, Cambridge, MA 02138, USA.
Vision Res. 1999;39(25):4186-91. doi: 10.1016/s0042-6989(99)00126-1.
Kelly ((1975) Science, 188, 371-372) showed that a centrally-fixated, contrast-reversing edge has a very different effect on the detection of luminance and red-green flicker. Red-green flicker sensitivity was approximately 3-fold greater for a uniform field than for a 'split' field with the two sides flickering out-of-phase. Just the opposite effects were observed for luminance flicker--the split field yielded a 7-fold advantage over the uniform field at 2 or 4 Hz and a 3-fold advantage at 12 Hz. Contrary to Kelly, we find that the split field offers only a very small advantage of 40% for luminance flicker at 2 Hz and virtually no advantage at 4 Hz and above. Kelly's chromatic results are surprising since one might expect that the larger color difference (or step) across the central edge would aid chromatic discrimination rather than strongly suppressing sensitivity. We show that the central chromatic edge only weakly impairs detection. Further results show that the two sides of the chromatic split field are detected essentially independently by red or green 'blob' detectors, which do not take advantage of the color difference across the edge. This has a remarkable implication: when wavelength discrimination is measured with a bipartite field whose two side are slowly modulated in opposite directions, then one side may be deleted with little adverse effect.
凯利（(1975)《科学》，188卷，371 - 372页）表明，一个中央固定的、对比度反转的边缘对亮度检测和红 - 绿闪烁的影响截然不同。对于均匀场，红 - 绿闪烁敏感度大约是两侧异相闪烁的“分割”场的3倍。对于亮度闪烁则观察到相反的效果——在2或4赫兹时，分割场比均匀场有7倍的优势，在12赫兹时有3倍的优势。与凯利的研究结果相反，我们发现分割场在2赫兹时对亮度闪烁仅提供40%的非常小的优势，在4赫兹及以上时几乎没有优势。凯利的色度学结果令人惊讶，因为人们可能预期中央边缘处较大的颜色差异（或阶跃）会有助于颜色辨别，而不是强烈抑制敏感度。我们表明中央色度边缘只会轻微损害检测。进一步的结果表明，色度分割场的两侧基本上是由红色或绿色的“斑点”探测器独立检测的，这些探测器没有利用边缘处的颜色差异。这有一个显著的含义：当用一个二分场测量波长辨别，其二侧在相反方向缓慢调制时，那么一侧可以被删除而几乎没有不利影响。
