that differed in how fast they could be learned. Their
findings indicate that, in rats, discrimination learning
is primarily supported by the dorsal striatum and they
rely heavily on a habit-based memory strategy even for
tasks that take only a few trials to acquire, thus regardless
of whether the task is learned rapidly or only
gradually. These considerations lead to the suggestion
that rodents may learn object discrimination tasks differently
than either monkeys or humans. Both monkeys
and humans with hippocampal lesions showed impairment
in the acquisition and retention of simple object
discriminations. In contrast, rats with hippocampal
lesions are either intact or only modestly impaired;
therefore, for rats, the dorsal striatum appears to have
the most important role.