On Brogaard’s view, certain recent studies point in just such a direction. In the way of empirical findings, the author highlights three separates cases on the effects of aging, conscious identity formation, and psychiatric treatments. Of the first, Brogaard summarizes:
For example, studies indicate that personality tends to change as we get older. This kind of change is often triggered by transformative episodes in life such as buying a house, getting an education, getting a job, getting married, becoming a parent, raising children and seeing them leave the nest. Age-related personality changes are for most part positive. We tend to become more agreeable, more conscientious and more sociable as we age.
Indeed, this study seems to confirm what a great number of commonly held intuitions about getting older. The life events to which people are exposed at later ages cannot help but change their approach to that same life. Again, this much can be granted, but examination of the study’s findings suggest that such changes owe less to alterations in the biological substrate, as would be needed to conform to the “plaster hypothesis”, which, in its weaker versions, allows only for gradual change in five major personality indicators.
Rather, on a contextual view, the changes would derive from changes in environment and the person’s exchanges with this environment in such a way that, at most, changes in the biological substrate accompany changes in (exchanges with the) environment. So, it is unclear how large a role Brogaard’s assertion about changes in the biological substrate provoking changes in first-order properties or personality traits can play in moving contemporary approaches to personality closer to a view not “set like plaster”.
The second case leans more heavily on the conscious imaginings of their selves to which people are given during their “formative” years.
Regardless of your adult age, most of us cannot imagine being altogether different in the future. One reason for this may be that after the teen years we tend to create a very strong sense of identity that is consciously presented to us. This sense of identity apparently can be so vivid that it is unimaginable that we could ever radically change. But we do. Of course, that personality does change should not come as a great surprise from a genetic point of view. Genetic research, particularly twin studies, suggest that personality is about 50 percent inherited and 50 percent due to things unrelated to heritage.
In short, either the conditions under which this imagining takes place or illusions concerning the object so imagined generate a sense of inevitability thereabout. Having a vivid representation of an essential, non-empirical object like self leads the person to believe that the object in question remains inviolable, inalterable, unavailable to environment. In simpler terms, the person is who she is for life.
These views prove, however, belied both by everyday experience, as suggested above, and by the genetic research to which Brogaard alludes. Recent genetic studies, on twins and on others, posit a similar heterogeneity of sources for personality, one part genetics (or biological substrate), one part environment.
One research group conducted, in this vein, a study on twins’ voting habits. Therein, the political leanings of identical and fraternal twins were examined, and it was found that identical twins, having near identical substrates and environments, were more likely to vote in the same way than fraternal twins, having substantially different substrates (like siblings) but near identical environments. At the level of political leanings, the study suggests that genetics would then play a more important role than environment. Such findings could lend further force and credence to the role played by the biological substrate.
The last case centers on psychiatric treatment and whether the person might consciously set out to change her personality.
A question relating to personality that remains highly controversial is whether we can willfully change our personality. Recent findings suggest that we can, at least in the context of therapy. In a meta-analysis of 144 studies Psychologist Brent Roberts from the University of Illinois at Urbana-Champaign and colleagues found that psychiatric treatments can induce personality changes within a time span of four to seven months, and these changes appear to last several years following treatment. The studies included more than 15,000 participants who had undergone an assessment of personality traits as well as some form of psychiatric treatment, such as talk therapy, antidepressants, meditation, or cognitive training. The researchers found that there was a significant change in personality traits in people who participated in the psychiatric interventions compared to people in the control groups. People with psychological disorders saw the greatest change, but even healthy participants experienced significant shifts in personality. The traits that changed most were people’s degree of neuroticism and introversion. There is a good reason for this. Neuroticism often is accompanied by depression and generalized anxiety, whereas introversion often leads to social anxiety and performance anxiety. So, by using therapy or medication to treat mood disorders, such as generalized or social anxiety, you are likely to change the personality types they fall under, namely neuroticism and introversion.
In sum, the meta-analysis concludes favorably on the ability of clinical therapy to generate substantive personality changes. Perhaps this is due, at least in part, to the way in which the first-order properties of personality become available to consciousness and, by extension, to both therapeutical and medical approaches. Again, this seems to owe not so much to changes in the biological substrate as to changes in the first-order properties themselves, which stem more from environmental stimuli than biological. Despite the clean, logical appeal of Brogaard’s suggestion that changes in the biological substrate would suggest similar, changes in personality, in the end, arguing to personality change from changes in the biological substrate proves, for the moment, inconclusive.