Advisers on mergers and acquisitions know that psychology plays a large part when big decisions are made. Factors such as the ambition of the chief executive, the pressure the board is under and the relationship between potential business partners are all likely to have an impact on whether a company pursues a deal or not.

But at least the decisions are logical. Or so it would appear. Studies out this month on chief executives' decision-making processes and risk-taking in M&A suggest that many of them rely on "gut feeling" and subconsciously make risky choices in the hope of enjoying a substantial upside should a deal go well.