The ancient Greeks developed the theory of humors, categorizing people into four types: phlegmatic, melancholic, sanguine, and choleric. For its time, this was a leading personality theory, based on what the Greeks understood about the body rather than the mind.

With hindsight, Eysenck demonstrated that the Greeks had identified two factors later validated within the Big Five. Lumina Spark refers to these as introversion/extraversion and risk orientation (risk-reactive vs. reward-reactive).

Carl Jung’s (1921) theory of personality marked a significant advancement beyond the humors and has served organizations well as a practical model for building self-awareness for many decades. Like the Greeks, Jung identified introversion and extraversion, along with two additional dimensions: thinking/feeling and intuition/sensing.

However, his work was based on case studies and anecdotal observations rather than statistical analysis. It is a testament to Jung’s insight that his theory correctly identified what would later be validated as three of the Big Five factors. Lumina Spark refers to these as Introversion/Extraversion, People Focused/Outcome Focused, and Big Picture Thinking/Down to Earth.

In 1936, Allport and Odbert compiled a list of over 4,500 terms in an effort to identify the core components of personality. In the 1940s, Raymond Cattell built on this work and proposed 16 personality factors. Later, Fiske (1949) identified limitations in Cattell’s analysis and concluded that five factors could account for personality variation. While Eysenck proposed three factors and Ashton later suggested six, the five-factor model gained increasing support.

It was not until the 1950s, when Tupes and Christal advanced this research, that the first formal version of the Big Five model emerged. Norman replicated their findings in 1963, and the model gradually became the dominant framework for academic personality research.

The 1960s and 1970s were challenging for personality research, as behaviorists and other academics questioned its validity (notably Mischel’s 1968 critique of trait theory). However, in the business world, these concerns had limited impact. Practitioners continued to use personality models—often based on Jung’s work—favoring what worked in practice over purely academic debates.

Myers and Briggs expanded Jung’s model, adding another dimension to align more closely with the Big Five. Meanwhile, researchers such as Digman and DeYoung identified higher-order factors that grouped the Big Five into broader domains. More controversially, Musek proposed a single general factor of personality. While academically interesting, this “Big One” has seen little practical application. Overall, the momentum of research gradually returned in favor of personality theory.

In the 1980s and 1990s, the Big Five became the leading academic framework, with Costa and McCrae’s model (1992) setting the standard for research. Lumina Spark was designed to integrate best practices from both Big Five and Jungian models for use in selection and development within organizations.

In particular, Lumina Spark retains the Jungian principle of valuing both ends of each spectrum equally—without resorting to rigid personality “types.” It combines the empirical rigor of Big Five research with a practical, intuitive Jungian lens to help individuals understand their personality.

In 2009, the Lumina Spark model was embedded into Lumina Learning’s cloud-based platform, making innovative digital solutions accessible to clients around the world.