Change blindness refers to the phenomenon that the surface characteristics of objects change significantly in a short time, but human beings can't detect it.
According to the above definition, which of the following is not change blindness?
A student was asking Xiao Li for directions. It happened that someone carried the blackboard between them. Then Xiao Li told each other how to go, but he didn't find that the person was not the student who had just asked for directions.