Final answer:
The invisible hand theory emphasizes self-interest as the predominant idea, where individual pursuit of personal gain contributes to the broader social good in a free market economy.
Step-by-step explanation:
When considering the invisible hand theory, the idea most prevalent is self-interest. This concept is grounded in the belief that individuals acting in their own personal economic self-interest can inadvertently contribute to the overall good of society, even if that is not their intention. The invisible hand metaphor, coined by economist Adam Smith, illustrates how self-interest drives actors in a free market to produce goods and services that are valued by others, thus benefiting the community at large.
As each individual strives to maximize personal gain, resources are allocated efficiently and the wealth of society as a whole can increase. Therefore, when people engage in economic activities for personal gain, broader social benefits often result, as though guided by an 'invisible hand.'