He highlights how both patience and impatience have neurological roots. Both can be self-reinforcing, with patience unlocking growth and prosperity but impatience generating over-trading and under-investment. Andrew Haldane explains that patience is likely to have been a key factor in the evolution of economic and financial systems. He says: "At root, banks and capital markets are simply a means of matching saving to investment. They are about realising the benefits of patience and thus growth. There is strong evidence for such effects. Financial deepening is known to be an important determinant of long-run growth.financial intermediation increases the returns to patience, thereby encouraging thrift and promoting growth".