Individual talent and initiative was recognized as an intangible quality of persons in economics back to at least Adam Smith. He distinguished it (as "enterprise") from labour which can be coerced and is usually seen as strictly imitative (learned or transmitted, via such means as apprenticeship).
Marxist economics refers instead to "an individual'ssocial capital—individuals are sources neither of creativity and innovation, nor management skill. A problem with that analysis is that it simply cannot explain the substitution problem and lack of demand that occurs when, for instance, an understudy takes on a leading role, or a second author takes over writing a popular book series. At the very least there must be some conditional, if not firm-specific then "class specific", special ability to command premiums for outstanding personal performance.
Versus "human", "firm-specific", "individual social"
While conflated in many analyses with human capital, the latter term includes social capital (human relationships) and instructional capital (abstract texts and training materials and so on) that are not tied to any one person, do not die with them or leave employment with them, and therefore cannot be equated with talent alone.[citation needed] In intangibles measurement, value creation and value reporting metrics require all assets with such different characteristics to be categorized as different capital assets, so the more exact reference to the individual person is preferred.
Fusions of terminology are common. Sociological analysts refer to "individual-level elements of social capital" or "an individual's social capital" or just "individual social capital" while economic analysts often use the phrase firm-specific human capital. In either case the clearly includes individual capital but also some "activity-", "community-" or "firm-specific" social capital (community trust) and instructional capital (shareable knowledge or skills). This is easy to measure: its yield is your salary in your current job.
To the degree this is consistent if you take other work nearby, this opens the questions of what is not "firm-specific" and whether a nation is just a bigger "firm": Some analyses see political capital, or just "influence" or "trust of professionals" as a full style of capital of its own. Some ethicists, most clearly Jane Jacobs, see this as simple corruption. Nonetheless, corruption clearly has a cash value, involves some creativity to arrange, and is a decision factor. It is a skill like any other.
Versus "intellectual capital"
Perhaps because of this, not all theorists recognize individual capital as being as essential as labour, or distinct from social or political influence, or from instructional capacity. These theorists often refer to "intellectual capital", which more properly describes a debate or locus of complexity that arises when individuals take key instructional roles. Some refer to celebrity as another fusion, when individuals take key social roles.
However, a great many celebrities are clearly not "intellectual" achievers nor notable for any cognitive or analytic powers, e.g. Kim Kardashian, professional sports figures or other athletes. While they may through sheer exposure become involved in causes or controversies (as Paris Hilton did in the US presidential election, 2008) it's clearly not correct to label all individually unique talent or economic value as being an "intellectual" asset.
This failure to distinguish individual's objectively observed economic value (the power to promote or publicize products, draw attention to causes, etc.) from the "intellectual" powers is probably an elitist bias. Clearly, there are some individuals, including non-humans such as a racehorse, which have economic value unique to their individual body and being that cannot be captured or defined as an "intellectual" asset nor as a set of "social" relationships (because horses do not socialize in the sense humans do). Where slavery exists or has existed, there is clearly a value put on living bodies separate from their instructional or social selves.
Thus for analyzing historical or criminal economic activities, or even professional sports, the instructional capital vs. individual capital vs. social capital distinction is essential.
Investment
Those who differentiate individual capital tend to see it as something that one can invest in, directly, and see growth, directly. For individual skill, even skill at a highly imitative enterprise, like sports or mastery of a musical instrument, this is very often quite measurable. Many enterprises, for instance, a music conservatory or circus school or creative writing coach, are clearly making a living on the identification and (somewhat) measurable enhancement of the individual.