Adults associate the abstract domain of emotional valence with the relatively concrete domain of space: good is up and bad is down. But where does this association come from? One potential source is linguistic experience; we talk about being in high spirits or feeling down in the dumps. Another potential source is perceptuo-motor experience; we stand upright when were happy, and slouch when were sad. Here we studied 5- to 10-year-old children to investigate the roles of linguistic and bodily experience in the formation of mental metaphors. Corpus analyses showed that children rarely use spatial language to communicate valence. Yet, children demonstrated strong space-valence mappings in a series of diagram tasks (e.g., when asked to place positively- or negatively-valenced items along a vertical axis, they consistently placed positive items up and negative items down). Results suggest that mental metaphors from space to valence may originate in perceptuo-motor experience.