A change is correctly detected (i.e., a hit occurs) if, and only if, either of the following two mutually exclusive events occurs: (i) the changed item is held in memory or (ii) the changed item is not held in memory but the observer guesses that there was a change.
![[This page as RDF]](http://data.gesis.org/somesci/static/rdf-icon.gif){kind=icon}