Setting the „signal suppression hypothesis“ to a stress test. Experiments to breakup the circular argumentation using behavioral findings and the lateral distractor positivity (Pd)

“信号抑制假说”的一个中心预测是视觉搜索中显著干扰刺激的主动抑制/抑制。在干扰物的特征预先已知的条件下，在"捕获探针”设计中的行为数据表明，对叠加在搜索显示刺激上的字母的识别低于对非目标刺激下的字母的识别。与干扰物阳性（Pd）的发生一起，干扰物阳性是与目标刺激一起呈现的相应干扰物对侧的视觉诱发电位的正向分量，具有约200 ms的潜伏期，这被视为模型的实验证据。然而，对于这两个因变量，可能有其他解释。非目标刺激总是具有与目标相同的颜色，基于全局特征的非目标刺激易化可能是可能的。如果是这样的话，这里的较高的字母识别率将是促进的结果，而不是抑制/抑制。此外，将Pd解释为刺激抑制/抑制的神经特征还远未确定或明确。一些研究提供的结果与这一解释不一致。在目前的项目中，我们打算将Pd设置为压力测试，以检查/仔细检查其普遍接受的功能意义，作为干扰抑制/抑制的神经信号。拟议的项目计划作为一个双中心项目与特伦托大学的精神/脑科学中心（CIMeC）一起记录我们的研究结果的可靠性，因为结果可能会质疑Pd的主动抑制帐户的一些关键预测。在项目结束时，我们希望我们的结果将迫使需要重新制定一些研究，并可能质疑一般的主动干扰抑制/抑制的想法。

A central prediction of the „signal suppression hypothesis“ is the proactive suppression/inhibition of salient distractor stimuli in visual search. Under the condition that features of the distractor are known in advance it was shown with behavioral data in the „capture probe“ design that recognition of letters superimposed upon stimuli of the search display was below the recognition of letters at non-target stimuli. Together with the occurance of the distractor positivity (Pd), a positive going component of the visual evoked potential contralateral to the respective distractor that is presented together with a target stimulus, having a latency of about 200 ms, this was seen as experimental evidence for the model. However, for both dependent variables alternative interpretations are possible. The fact that non-target stimuli always had the identical color as the target, global feature-based facilitation of non-target stimuli might be possible. If that were the case, higher letter recognition here, would be a consequence of facilitation and not suppression/inhibition. Further, the interpretation of the Pd as a neural signature of stimulus suppression/inhibition is far from beeing settled or unambigously clear. A number of studies provided results that were at odds with that interpretation. In the current project we intend to set the Pd to a stress test to check/scrutinize its commonly accepted functional significance as neural signature of distractor suppression/inhibition. The proposed project is planned as a dual center project together with the Center for Mind/Brain Sciences (CIMeC) of the University of Trento to document the reliability of our findings, because results might question some of the crucial predictions of the active suppression account of the Pd. At the end of the project we expect that our results will force the need to reformulate a number of studies and might question the idea of proactive distractor suppression/inhibition in general.