Hormones are chemical messengers that have a specific physiological effect in the body. Research suggests that hormones also have considerable influence on behaviour and emotion in both human and non-human animals. This supports the notion that behaviour and emotion have physiological origins. It is not appropriate, however, to say that hormones cause behaviour but that hormones influence behaviour. Research highlights the interaction between physiological factors and environmental stimuli, supporting a correlational effect. (With thanks to our sponsor 'Curriculum Press' for providing content for this podcast)