 In the model organism, nematode "Caenorhabditis elegans", it reduces locomotion and increases food-exploratory movements; in flatworms it produces "screw-like" movements; in leeches it inhibits swimming and promotes crawling.Across a wide range of vertebrates, dopamine has an "activating" effect on behavior-switching and response selection, comparable to its effect in mammals.Dopamine has also consistently been shown to play a role in reward learning, in all animal groups.