Rothkegel Lars O M, Trukenbrod Hans A, Schütt Heiko H, Wichmann Felix A, Engbert Ralf
University of Potsdam, Potsdam, Germany.
Eberhard Karls University, Tübingen, Germany.
J Vis. 2017 Nov 1;17(13):3. doi: 10.1167/17.13.3.
When watching the image of a natural scene on a computer screen, observers initially move their eyes toward the center of the image-a reliable experimental finding termed central fixation bias. This systematic tendency in eye guidance likely masks attentional selection driven by image properties and top-down cognitive processes. Here, we show that the central fixation bias can be reduced by delaying the initial saccade relative to image onset. In four scene-viewing experiments we manipulated observers' initial gaze position and delayed their first saccade by a specific time interval relative to the onset of an image. We analyzed the distance to image center over time and show that the central fixation bias of initial fixations was significantly reduced after delayed saccade onsets. We additionally show that selection of the initial saccade target strongly depended on the first saccade latency. A previously published model of saccade generation was extended with a central activation map on the initial fixation whose influence declined with increasing saccade latency. This extension was sufficient to replicate the central fixation bias from our experiments. Our results suggest that the central fixation bias is generated by default activation as a response to the sudden image onset and that this default activation pattern decreases over time. Thus, it may often be preferable to use a modified version of the scene viewing paradigm that decouples image onset from the start signal for scene exploration to explicitly reduce the central fixation bias.
当在电脑屏幕上观看自然场景的图像时，观察者最初会将眼睛移向图像中心——这是一个可靠的实验发现，称为中央注视偏差。这种眼睛引导中的系统性倾向可能会掩盖由图像属性和自上而下的认知过程驱动的注意力选择。在这里，我们表明，相对于图像呈现延迟初始扫视，可以减少中央注视偏差。在四个场景观看实验中，我们操纵了观察者的初始注视位置，并相对于图像呈现延迟了他们的第一次扫视特定时间间隔。我们分析了随着时间推移到图像中心的距离，并表明延迟扫视开始后，初始注视的中央注视偏差显著降低。我们还表明，初始扫视目标的选择强烈依赖于第一次扫视潜伏期。一个先前发表的扫视生成模型通过在初始注视上的中央激活图进行了扩展，其影响随着扫视潜伏期的增加而下降。这种扩展足以复制我们实验中的中央注视偏差。我们的结果表明，中央注视偏差是由对突然的图像呈现的默认激活产生的，并且这种默认激活模式会随着时间下降。因此，使用场景观看范式的修改版本可能通常是更可取的，该版本将图像呈现与场景探索的起始信号解耦，以明确减少中央注视偏差。
