 Moreover, Atmanspacher and Filk (2010) showed that the Necker-Zeno model violates temporal Bell inqualitities for particular distinguished states in bistable  perception.[15]  This theoretical prediction is yet to be tested experimentally and would be a litmus test for quantum behavior in mental systems. Such states have been denoted as temporally nonlocal in the sense that they are not sharply (pointwise) localized along the time axis but appear to be stretched over an extended time interval (an extended present). Within this interval, relations such as “earlier” or “later” are illegitimate designators and, accordingly, causal connections are ill-defined.