FIGURE 3.

Confounded measure intended to index visual perception. In this example relevant to a diagnostic biomarker, a specific form of Visual Perception alteration is understood to be a consequence of ASD and is intended to be indexed by the Event-Related Potential (ERP). However, Visual Attention (such as looking at the stimulus display) is both necessary for task performance and is also systematically different between the ASD group and the control group. In this example, Visual Attention has a bigger impact on the ERP dependent variably (heavy arrow) than does the Visual Perception ability, and therefore confounds the interpretation of the ERP read-out as a valid measure of Visual Perception.