Devillez Hélène, Guérin-Dugué Anne, Guyader Nathalie
University of Colorado Boulder, USA.
Université de Grenoble-Alpes, France.
J Eye Mov Res. 2017 Apr 10;10(2). doi: 10.16910/jemr.10.2.2.
The distractor effect is a well-established means of studying different aspects of fixation programming during the exploration of visual scenes. In this study, we present a taskirrelevant distractor to participants during the free exploration of natural scenes. We investigate the control and programming of fixations by analyzing fixation durations and locations, and the link between the two. We also propose a simple mixture model evaluated using the Expectation-Maximization algorithm to test the distractor effect on fixation locations, including fixations which did not land on the distractor. The model allows us to quantify the influence of a visual distractor on fixation location relative to scene saliency for all fixations, at distractor onset and during all subsequent exploration. The distractor effect is not just limited to the current fixation, it continues to influence fixations during subsequent exploration. An abrupt change in the stimulus not only increases the duration of the current fixation, it also influences the location of the fixation which occurs immediately afterwards and to some extent, in function of the length of the change, the duration and location of any subsequent fixations. Overall, results from the eye movement analysis and the statistical model suggest that fixation durations and locations are both controlled by direct and indirect mechanisms.
干扰效应是研究视觉场景探索过程中注视程序不同方面的一种成熟方法。在本研究中，我们在参与者自由探索自然场景期间向其呈现一个与任务无关的干扰物。我们通过分析注视持续时间和位置以及二者之间的联系来研究注视的控制和程序设计。我们还提出了一个使用期望最大化算法评估的简单混合模型，以测试干扰物对注视位置的影响，包括未落在干扰物上的注视。该模型使我们能够量化视觉干扰物在干扰物出现时以及所有后续探索过程中相对于场景显著性对所有注视位置的影响。干扰效应不仅限于当前注视，它在后续探索过程中继续影响注视。刺激的突然变化不仅会增加当前注视的持续时间，还会影响紧接着的注视位置，并且在一定程度上，根据变化的时长、任何后续注视的持续时间和位置产生影响。总体而言，眼动分析和统计模型的结果表明，注视持续时间和位置均由直接和间接机制控制。
