The connection with psychology is intrinsic in the economy and is inseparable from it, and has been kept since the time of the classical school. Adam Smith, who has been regarded as the founder of the theory of the invisible hand in relation to the market – and even misunderstood to a certain extent – wrote an essay on the psychological principles of individual behaviour (Theory of moral sentiments, 1759.) It is with the development of neoclassical economics that economists …