“…The most probable distinguishing feature is stimulus odor because of rodents' high reliance on olfactory information. It has been shown that rats are capable of using odor to solve a number of complex tasks such as delayed matching to sample (Lu, Slotnick, & Silberberg, 1993), transitive inference (Bunsey & Eichenbaum, 1996), and spatial navigation (Whishaw & Gorny, 1999). Hence, it is possible that rats could solve the simple discriminations in these experiments based strictly on olfactory cues.…”