Hofstede, G. (1983). National cultures in four dimensions: A research-based theory of cultural differences among nations.

As per Hofstede, when it comes to the Individualism dimension for national/societal culture, individualism and collectivism are like two poles of a continuum (if my understanding is correct).

Following are two direct quotes from Hofstede's website on the definition of "culture" (social anthropology perspective) and one of the dimensions of National Culture proposed by Hofstede-individualism.

Culture

[Culture] refers to the way people think, feel,  and act. Geert has defined it as "the collective programming of the mind distinguishing the members of one group or category of people from another". The "category" can refer to nations, regions within or across nations, ethnicities, religions, occupations, organizations, or the genders. A simpler definition is 'the unwritten rules of the social game'.

Individualism-Collectivism

Individualism on the one side versus its opposite, collectivism, is the degree to which individuals are integrated into groups. On the individualist side we find societies in which the ties between individuals are loose: everyone is expected to look after her/himself and her/his immediate family. On the collectivist side, we find societies in which people from birth onwards are integrated into strong, cohesive in-groups, often extended families (with uncles, aunts and grandparents) which continue protecting them in exchange for unquestioning loyalty. The word collectivism in this sense has no political meaning: it refers to the group, not to the state. Again, the issue addressed by this dimension is an extremely fundamental one, regarding all societies in the world.

En route to the above direct quote, I went back to the following article and took some notes.

Hofstede, G. (1983). "National cultures in four dimensions: A research-based theory of cultural differences among nations." International Studies of Management & Organization: 46-74.

"Individualism (IDV) indicates the relative importance in the country of the job aspects personal time, freedom, and challenge and relative unimportance of training, of use of skills, of physical conditions, and of benefits.  It thus stresses goals in which the individual is an active agent versus those in which he or she is dependent on the organization (being trained, skills being used, working conditions, and benefits being provided).

... the individualism index indicates (non-) dependence on the organization." (p. 54)

"The fact that the Hermes data were measured twice, around 1968 and around 1972, allows some conclusions about world-wide shifts on the four dimensions during this period.  The dimension showing the largest universal shift is individualism .... On the dimension of individualism, there was some reduction in the distance between extreme countries, so that we can speak of a certain convergence over time." (P. 70)

"... in individualism, [the long-term trend is] very clearly [one] of decrease." (p. 71)