 Kent Berridge, a researcher in affective neuroscience, found that sweet ("liked" ) and bitter ("disliked" ) tastes produced distinct orofacial expressions, and these expressions were similarly displayed by human newborns, orangutans, and rats.This was evidence that pleasure (specifically, "liking") has objective features and was essentially the same across various animal species.Most neuroscience studies have shown that the more dopamine released by the reward, the more effective the reward is.