Scholarship has suggested that environmental factors and genetics have a role to play in personality development. Thus, environmental conditions and inherited genetic traits shape an individual’s personality. Although the environment has been demonstrated to affect personality traits, it has been suggested that heredity factors are more influential in shaping the disposition of the environment.
The effect of genetics in personality development is exemplified by the case of schizophrenia, which represents a hereditary deficiency that cannot be counteracted by environmental factors. Picchioni et al. (2010) demonstrate that schizophrenia is significantly correlated with childhood and adolescent deficiencies in personality and social adjustment. The relationship between genetic factors and personality development is also exemplified by Flom & Saudino (2017), who show that genetic aspects are associated with callous-unemotional behaviors among children aged two and three years. According to Briley & Tucker-Drob (2014), the effect of genetic and environmental factors on personality tend to increase in constancy with age. The influence of genetic factors to one’s phenotypic stability is middling in magnitude and moderately constant with age due to the small and moderate decreases in heritability of personality that equalize increases in genetic stability.
Environmental factors are also critical in the development of personality. Environmental conditions dictate the circumstances in which personality changes. The influence of the environment on personality depends on their interaction with environmental situations. For instance, individual personality differences in old age have been traced to environmental factors (Kandler, Kornadt, Hagemeyer, & Neyer, 2015). Environmental influence is also observable in people’s personality traits. Ilmarinen et al (2019) show that sociometric status (relationship between the individual and the group) can repetitiously and simultaneously affect micro-level personality processes.