Movements of our muscles influence our thoughts and emotions. People given neutral bland instructions to contract the specific face muscles that make a smile find it harder to generate a feeling of anger when requested to do so, and instruction to move the muscles that make an angry frown make it harder to follow a subsequent instruction to feel friendly or happy. Havas has found that blocking a frown can actually prevent a bad mood. Natalie Angier summarizes several studies that show the opposite: how thoughts influence our muscle movements in subtle ways. Miles et al., for example, show that when we thing of events in the future, our bodies move slightly forward, while thinking of past events causes them to move slightly backwards. Their observations are consistent with theories of "embodied cognition," in this case mental time travel may be represented in the sensorimotor systems that regulate human movement. The metaphorical “arrow of time” may be grounded in a processing architecture that integrates temporal and spatial information in a directional manner (i.e., past = back, future = forward).
Angier also notes other work on embodied cognition that I have mentioned - Students who held a hot cup of coffee in their hand were more likely to evaluate a target person as being warm and friendly than those holding a cold cup of coffee. She notes work (this post) showing that a warm versus cold stare causes subject to evaluate the temperature of a room as warmer. Finally she points to work (this post) showing our bodies conflate weight with greater importance or value. (...almost makes you think that both Angier and Bownds scan the contents of the journal "Psychological Science.")