There is a key distinction is between personality and behaviour. The word "personality" has many uses (many of which are wrong!) and many definitions. Essentially, personality is taken to mean a mix of values, world-views, set responses and characteristics which are relatively enduring aspects of the person. Personality is taken to be what we are while behaviour is what we do. We cannot change what we are but we can change what we do - for short periods of time at least. The ability to change behaviour is at the root of the concept of management style.
As Robin Stuart-Kotze says,
"... it has been maintained ... that personality becomes virtually fixed at about age five. Current research indicates that we are more flexible than that but that changing one's attitudes, values, beliefs and aspirations - the substance of personality - is difficult"
Behaviour, on the other hand, is what we do. While much of our behaviour (see Theory X and Theory Y) is of course the result of our values and beliefs, it is much easier to behave differently (if only for a short while) than to change beliefs. Moreover, if we try out different behaviours - different ways of doing things - and find that they are a success, this in itself may cause us to change even deeply held views and values.
For more information on our programmes looking at behaviour, leadership and team development then visit Call of the Wild's website