The use of scene context is a powerful way by which biological organisms guide and facilitate visual search. Although many studies have shown enhancements of target-related electroencephalographic activity (EEG) with synthetic cues, there have been fewer studies demonstrating such enhancements during search with scene context and objects in real world scenes. Here, observers covertly searched for a target in images of real scenes while we used EEG to measure the steady state visual evoked response to objects flickering at different frequencies. The target appeared in its typical contextual location or out of context while we controlled for low-level properties of the image including target saliency against the background and retinal eccentricity. A pattern classifier using EEG activity at the relevant modulated frequencies showed target detection accuracy increased when the target was in a contextually appropriate location. A control condition for which observers searched the same images for a different target orthogonal to the contextual manipulation, resulted in no effects of scene context on classifier performance, confirming that image properties cannot explain the contextual modulations of neural activity. Pattern classifier decisions for individual images were also related to the aggregated observer behavioral decisions for individual images. Together, these findings demonstrate target-related neural responses are modulated by scene context during visual search with real world scenes and can be related to behavioral search decisions.

场景上下文的使用是生物有机体引导和促进视觉搜索的有力方法。尽管许多研究表明使用合成线索可以增强与目标相关的脑电图活动（EEG），但在现实世界场景中使用场景上下文和对象进行搜索时，很少有研究表明这种增强。在这里，当我们使用EEG来测量对不同频率闪烁的物体的稳态视觉诱发反应时，观察者秘密地在真实场景的图像中寻找目标。当我们控制图像的低级属性（包括目标相对于背景的显着性和视网膜偏心率）时，目标出现在其典型的上下文位置或上下文之外。使用在相关调制频率上的EEG活动的模式分类器显示，当目标位于上下文适当的位置时，目标检测精度会提高。观察者在相同的图像中搜索与上下文操作正交的不同目标的控制条件，导致场景上下文对分类器性能没有影响，从而确认图像属性无法解释神经活动的上下文调制。单个图像的模式分类器决策还与单个图像的聚集观察者行为决策有关。总之，这些发现表明与目标相关的神经反应在真实世界场景的视觉搜索过程中受场景上下文的调节，并且可能与行为搜索决策有关。