Accordingly with four pairs of fundamentally opposed preferences, it is easy to see how divergent styles can cause the opposite type much stress, and how disagreements can arise when no common understanding exists of another’s paradigm.

One of the key points about preferences is that no matter what natural preference a person may have, the opposite preference can be used, if in a less skilled manner. To take ‘handedness’ as an example – nearly everyone writes with a preferred hand, and once proficient writes with this hand without conscious effort. However, it is possible to write with the non-preferred hand, and with practice and conscious exertion an individual may become quite skilled, but innate handedness does not change and s/he will always revert back to the preferred hand whenever possible.

It is the same when using our mental functions. Jung discovered that people used functions in a hierarchy of preference. He described the order from the most used mental process – the dominant function, through the auxiliary and tertiary function with the least preferred known as the inferior function. We can and do use all of four functions but most of us have a preferred well-developed function we rely on. This superior function is supported by the auxiliary function which too can normally be used at will. The tertiary function however, is somewhat less developed and depending on how evolved the person, may or may not be under conscious control. The inferior function is invariably poorly developed. Buried deep in the unconscious it is unskilled and unpractised, and when in times of great stress it bursts through, it causes havoc and surprise to the individual as well as those around who may be mystified as the person is “acting out of character”.

The interaction between the functions is dynamic. Each pair of opposites are at different ends of a continuum, and if one pole is extraverted the other will be introverted. Hence, dependent on whether the individual is extraverted or introverted, s/he may or may not use their most developed function in the outside world. While extraverts use their dominant function in the external world, Introverts’ dominant function is internalised and the individual relates to the external world through their extraverted auxiliary function.

The various combinations of these preferences result in 16 personality ‘types’ represented by four letters. The resulting gestalt of each four letter type, for example ESTJ, INFP is far greater than the sum of the individual letter parts. Each type is associated with a unique set of values and behavioural characteristics which provide a useful starting point for individual feedback, self-exploration or group discussion.