There is a personality trait we carry throughout life that explains why some of us find it easier to change than others
Have you ever felt as though someone important to you, such as your best friend, was starting to become a completely different person? At the same time, perhaps you have the opposite problem – no matter what you do or how hard you try, you can never seem to break old habits and you find yourself struggling to change for the better. How can these two realities – some people appearing to completely change who they are, while others find themselves unable to make any changes – coexist?
When you think about how much you or others can change deep down, what you are really considering is personality – a person’s typical thoughts, feelings and behaviours as they go through their daily life. Your best friend’s personality seems to have changed profoundly, yet your personality seems entirely fixed. This striking contrast echoes a long-running debate in psychology. For a long time, psychologists saw personality as fixed throughout our lives. This has since been disproven – although personality is relatively stable, it’s far from set in stone.
Typically, most personality changes occur in young and older adulthood, with middle age appearing to be the period of the greatest stability. Changes in personality can be driven by the natural ageing process or the influence of external factors, such as major life events and daily interactions with other people.
While there are average trends of change in each of the so-called Big Five personality traits – such as agreeableness typically increasing with age, whereas neuroticism decreases – people also vary as individuals in the ways that they change. For instance, although the average trend is for most people to increase in agreeableness, others can remain quite stable, and yet others might show decreases. This mixed picture of average trends and individual variability is true for all Big Five traits (alongside agreeableness and neuroticism, that includes extraversion, conscientiousness, and openness).
Another way to think about this is to consider how people tend to change in their entire personality across time – ie, their personality profile as reflected across all the Big Five traits. If there are individual differences in how stable single traits are, are there also individual differences in how stable entire personality profiles are? Indeed, in our recent research, my colleague Joshua Jackson and I found that some individuals are simply more stable in their personality profiles than others – suggesting this quality of stability can itself be a dispositional characteristic. That is, whereas you might be relatively steadfast in how you respond to questionnaire items assessing all of the Big Five traits (ie, your Big Five personality profile), thus showing heightened levels of personality stability, your best friend could reliably change more frequently in their scores, thus showing general levels of instability.
A long-term career, partner and dwelling can increase a person’s personality stability by making someone more ‘who they are’
We made this finding by examining repeated personality test scores for more than 20,000 individuals and seeing how much each individual’s test scores tended to correlate (ie, remain consistent) over time. We found that people varied in their initial levels of profile stability: some had profile correlations such as .30 (indicating low levels of stability, with greater changes occurring across two time points) while others had profile correlations such as .80 (indicating high levels of stability, with fewer changes occurring across two time points). What’s more, as our study progressed, these individual differences in profile stability persisted. We found that, over a duration of more than a decade, people maintained their own typical levels of profile consistency – overall, those with stable personalities tended to remain stable, and those people with unstable personalities tended to remain unstable. The quality of being stable in your personality traits appears to be a trait in and of itself! This could explain the hypothetical story of your friend’s changing personality in contrast to your own apparent rigidity.
Why are some people more stable than others in their personalities? Past research has shown three processes that underlie personality stability: developmental constants, such as genetic or biological factors and/or early life experiences, which can establish and maintain one’s level of personality stability; environmental factors such as a long-term career, partner and dwelling, which can increase one’s personality stability by making them more ‘who they are’ and solidifying their qualities across time; and, lastly, stochastic or random factors, such as unexpected life changes or things that lead someone to deviate from the typical status quo of their life, which can reduce their levels of stability.
As shown by our research, people usually maintain their person-typical levels of stability across time – we think this is due to the developmental constants, which are a strong presence in most individuals’ lives and set their personal level of stability. In the rare cases where an individual’s personality consistency changes, this likely reflects the influence of the environment (which usually increases stability) or stochastic factors (which reduce it). Thus, how stable you are is a byproduct of your own disposition (a quality you carry within yourself), your environment and the life experiences you’ve accumulated thus far. It is likely that all three processes co-exist within each individual’s life – but it is the certain combination of them and their influence on an individual that results in their own unique level of personality stability and the changes in it across time.
The quality of personality stability has implications for your life and how you think about yourself. If you are someone who has the tendency to remain consistent in your personality, it might suggest that you are less capable of changing who you are. Although this does not preclude the chance that change is possible, your personality is robust against external influences. It is likely you have gone through certain maturational milestones – such as graduating from school, starting a career, and finding a long-term partner – and other life experiences that research shows can often change personality, yet they have not changed you. The positive side of this is that people around you have likely come to expect you to act a certain way, and rely on that feeling of familiarity with who you are. However, it could also suggest that you will have difficulty trying to change or reinvent yourself because your typical pattern of thoughts, feelings and behaviours are enduring and resistant to change.
Recognising this quality of personality (in)stability can be instrumental in learning how best to navigate a relationship
The reverse is true if you have relatively low personality stability – your friends and family might find your apparent fickleness a little disorientating, and it might have implications for your sense of a coherent self, yet optimistically it also suggests that you are capable of change, including for the better.
The quality of personality stability also has implications for how you think about and interact with people you know. You can doubtless describe various aspects of their personality pretty well – if a friend is often early or late to something; if they have mood swings or are of a more calm, steady temperament; or if they prefer to be the centre of attention or more of an outside observer in social settings. Some of these characteristics you may view as their cardinal, or primary, qualities: the things that define who they are. This ability to describe those close to you in life may come in handy at times. For instance, if you view a close friend as someone who is just habitually late to things, it may make it easier to overlook as it becomes habitual and something you come to expect from them. An implication of our research is that you could take a similar perspective about how stable they are in their personality.
If you have ever found yourself frustrated with someone who seems to either always be changing their identity, picking up new habits nearly as quickly as they lose them, or has unpredictable behaviour such that you never really know what to expect them to do next, it may have been easy to see that inconsistency as a flaw. Conversely, similar annoyances can arise when dealing with someone who appears almost frustratingly the same. For example, perhaps they are unwilling to deviate from established routines; they say they will work on a behaviour or quality that has caused issues for them in the past but to no avail; or you find they are unsettled when other people start changing, as this notion runs counter to how they live their own life.
For the first person, some words to describe them may be ‘unreliable’ or ‘inconsistent’, whereas the second person may be described as ‘rigid’ or ‘stubborn’. However, based on our findings, I suggest that, instead of ascribing these qualities, which often have negative connotations, to these people, it may be more appropriate and beneficial for relationships to view the stability of who they are as its own unique characteristic. Instead of viewing their patterns of behaviours as a failure to change (or to stop changing who they are), it can be adaptive to recognise them as a defining quality of theirs that you can come to expect them to continue exhibiting. Thus, much like your habitually late friend whom you no longer get annoyed with because you have learned to allot them an extra 10 minutes whenever you do something together, recognising this quality of personality (in)stability in those around you can be instrumental in learning how best to navigate a relationship.
Although being highly stable or unstable may not seem the most adaptive, I should add the good news that, like many other psychological characteristics, most people have an average level of consistency that falls somewhere in the middle. Having this relatively stable yet still somewhat open-to-change personality system means that, not only are you able to naturally experience personality change, but you and the people close to you can maintain some stable sense of ‘who you are’. Additionally, you also have some level of malleability to work with if there is some quality about yourself you wish to reinvent.
Overall, many ideas and constructs in psychology have found their way into the general population. Personality traits are an exceptional example of this – who isn’t interested in learning more about why they are the way they are and how best to label and describe these qualities? I’m proposing that a sensible addition to the repertoire of public knowledge about personality, beyond the main traits, is the notion of personality consistency. With implications spanning from practical applications to navigating everyday social interactions, personality consistency is one individual difference that may forever change what we know about ourselves and others.
This Idea was made possible through the support of a grant to Aeon+Psyche from the John Templeton Foundation. The opinions expressed in this publication are those of the author and do not necessarily reflect the views of the Foundation. Funders to Aeon+Psyche are not involved in editorial decision-making.