Johnson Aaron P, Richard Bruno, Hansen Bruce C, Ellemberg Dave
Department Psychology, Concordia University, Montréal, Québec, Canada.
J Vis. 2011 Jun 17;11(7):14. doi: 10.1167/11.7.14.
Recent studies explored the sensitivity of human perception to natural images, in particular the sensitivity of the visual system to discriminate changes in the amplitude spectrum slope. Previous slope discrimination experiments were carried out with stimuli presented either in the fovea or the parafovea/periphery and show that both yield poor discrimination at very steep or relatively shallow slopes. We verified if the well-known center-surround spatial interactions that operate early on in the visual processing stream influence the perception of real-world images. The results show that amplitude slope discrimination is greatly reduced (i.e., flat) when the stimulus is viewed in isolation. However, when a 2° target is placed within a surround containing an amplitude spectrum slope of 1 or 1.3, we see significant facilitation in detecting variations in the slope of the amplitude spectrum, particularly when the target contains an amplitude spectrum slope of 1 and 1.3. The results suggest that our visual system is sensitive to contextual interactions for stimuli that have the characteristics of natural images.
最近的研究探讨了人类感知对自然图像的敏感度，特别是视觉系统辨别幅度谱斜率变化的敏感度。先前的斜率辨别实验是在中央凹或中央凹旁/周边呈现刺激物时进行的，结果表明，在非常陡峭或相对较浅的斜率下，两者的辨别能力都很差。我们验证了视觉处理流早期起作用的著名的中心-外周空间相互作用是否会影响对真实世界图像的感知。结果表明，当孤立地观察刺激物时，幅度斜率辨别能力会大大降低（即变得平坦）。然而，当一个2°的目标置于包含幅度谱斜率为1或1.3的外周区域内时，我们在检测幅度谱斜率变化方面看到了显著的促进作用，特别是当目标包含幅度谱斜率为1和1.3时。结果表明，我们的视觉系统对具有自然图像特征的刺激物的上下文相互作用敏感。
