Taken together, the two studies seem to indicate a direct relationship between ability to express emotion through facial expression, and the ability to experience emotion oneself, or identify it in others.

FORBES: Botox May Deaden Ability to Empathize, New Study Says

To the contrary, the results indicate that happiness and income are connected by a two-way relationship, and that human well-being can itself be a source of economic dynamism.

FORBES: Investing In Psychological Well-Being Pays Off With Income Gains

Just this week, U.S. criticisms of proposed European data-privacy rules and plans to tax trades in financial instruments indicate the potential for future regulations to act as irritants in the relationship.

WSJ: Bartering Over a Trans-Atlantic Trade Deal

According to the Washington Post, it was here that he learned counter-intelligence tricks that became part of his relationship with their reporters: a flowerpot on Mr Woodward's balcony would indicate that the reporter required a meeting, while a clock face inked on the reporter's daily New York Times would reveal the time Mr Felt would be waiting in the car park.

BBC: Obituary: Mark Felt