Why do dogs make a beeline for underwear and smelly socks?

Why do dogs make a beeline for underwear and smelly socks? Also, do we really get taller at night, why do some colours reflect and others absorb light, does our skin get thinner as we age, and what's the basis of lisps and accents? Dr Chris Smith and Amy Maciver have the answers... Like this podcast? Please help us by supporting the Naked Scientists (thenakedscientists.com/donate)