Merryn Somerset Webb speaks with Alex Edmans, author of The Madness of Markets: Why Smart Investors Make Crazy Decisions – And How to Exploit Them, about why even sophisticated investors struggle to overcome the psychological biases that shape their decisions. Markets are driven by humans, and humans are emotional. Edmans explains how understanding the influence of emotion, herd behavior and over-confidence can help investors make better decisions — and potentially achieve better returns.