Partition two areas. Allow cats to sleep in either, but wake the cats who sleep in one of the areas midway through sleep. Also partition the cats into two groups: a group that is woken during REM sleep and a group that is woken during non-REM sleep.

As time passes, observe avoidance behaviors. If the cats woken during REM sleep more readily avoid the area in which they are awoken, then it is likely that not only are the cats dreaming, but that these dreams serve a training function.