Department of Experimental Psychology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany,
Behav Res Methods. 2013 Dec;45(4):1313-21. doi: 10.3758/s13428-013-0321-6.
Gaze-contingent displays provide a valuable method in visual research for controlling visual input and investigating its visual and cognitive processing. Although the body of research using gaze-contingent retinal stabilization techniques has grown considerably during the last decade, only few studies have been concerned with the reliability of the specific real-time simulations applied. Using a Landolt ring discrimination task, we present a behavioral validation of gaze-contingent central scotoma simulation in healthy observers. Importantly, behavioral testing is necessary to show whether the simulation impairs foveal processing of visual information. This test becomes even more crucial when researchers are faced with null results in a task performed with the scotoma, as compared with a control condition. It must be ruled out that the lack of behavioral effects results from a type II error caused by improper implementation before conclusions about foveal contributions to the given task may be drawn. In our experiment, the scotoma effectively prevented foveal processing of the visual stimuli, leading to significantly reduced response accuracies, as compared with unimpaired vision. Moreover, the final fixation at the time of the participants' responses was placed close to the target position in the unimpaired condition, whereas the distance to the target was enhanced with the scotoma, indicating that the observers were not able to discriminate visual target stimuli from distractors, due to the scotoma. The present work presents a validated behavioral testing method for the efficiency of gaze-contingent scotoma simulations, including code for implementation. In addition, solutions for common methodological problems are discussed.
注视相关显示为视觉研究提供了一种有价值的方法，可用于控制视觉输入并研究其视觉和认知处理。尽管在过去十年中，使用注视相关视网膜稳定技术的研究数量已经大大增加，但只有少数研究关注所应用的特定实时模拟的可靠性。我们使用 Landolt 环辨别任务，对健康观察者的注视相关中央暗点模拟进行了行为验证。重要的是，行为测试对于证明模拟是否会损害中央凹视觉信息处理是必要的。当研究人员在与暗点相比的对照条件下进行任务时，获得的结果为零，那么这种测试就变得更加重要。必须排除由于实施不当导致的第二类错误，从而导致缺乏行为效应，然后才能得出关于中央凹对特定任务的贡献的结论。在我们的实验中，暗点有效地阻止了视觉刺激的中央凹处理，与未受损视力相比，反应准确率明显降低。此外，参与者在响应时的最终注视点接近未受损条件下的目标位置，而随着暗点的出现，目标的距离得到了增强，这表明由于暗点，观察者无法从干扰物中辨别出视觉目标刺激。本工作提出了一种验证的行为测试方法，用于评估注视相关暗点模拟的效率，包括实现代码。此外，还讨论了解决常见方法学问题的方法。
