Advertising agencies and marketing people use different techniques to push our buttons. Humour is one. But what about fear? Do they sometimes try to scare us into buying? Or is it a gentler art- playing on our insecurities about things like old age, poor health or thinning hair? Evan Davis speaks to Sir John Hegarty and Ian Gathard from the advertising industry and psychologist Juliane Beard, who studies how the brains of consumers work.Credits: Volkswagen "Eyes on the Road" advertising stunt Reebok trainers advertisement: "Lose the Beer Belly" Aviva home insurance advertisementProduction team: Producers: Simon Tulett and Michaela Graichen Researcher: Drew Hyndman Editor: Matt Willis Sound: Neil Churchill Production co-ordinator: Katie Morrison(Picture: Piccadilly Circus in London, Light Trails at night. Credit: Jonathan Herbert, JH Images via Getty Images)