Adam Smith said that the individual "intends only his own gain, and he is… led by an invisible hand to promote an end which was not part of his intention." By this, Smith meant that.

Adam Smith said that the individual "intends only his own gain, and he is… led by an invisible hand to promote an end which was not part of his intention." By this, Smith meant that the market unintentionally regulates and benefits those who operate in it.

Explanation:

The Invisible Hand is a metaphor used by Scottish philosopher Adam Smith, the founder of modern economic thinking. The term refers to the individual who, in a well-functioning market economy (an economy where there is complete competition in all markets) will act for the benefit of himself and at the same time indirectly act for the benefit of society or the collective in the sense that the outcome will become economically efficient.

The idea of trade and the exchange market automatically channeling "self-interest" into "desirable social ends" is the central justification of the laissez-faire economic philosophy, which predates neoclassical economics.

what's this it's not giving you what have to do.

i believe the answer is:   psychological  experiment

in this experiment, wilhelm wundt became the first person that implement scientific method in analyzing the pyschological phenomenon.

due to this result, wilhelm wundt also able to make psychology to be acknowledged as a separate scientific field from biology.