The document describes a study that investigated delay discounting of qualitatively different food rewards in rats. It found that rats, like other non-human animals, did not show a magnitude effect when rewards differed in amount. However, the study aimed to extend this investigation by also examining if rats showed a magnitude effect when rewards differed in quality. The researchers tested rats' preferences for different food rewards and then measured how steeply they discounted rewards of varying quality and amount when choosing between smaller immediate and larger delayed rewards.