Throughout this chapter we have introduced you to some of the leading theories and theorists in the field of personality research. We have also given you some insights into how these theories can be applied in real-world situations. We began by examining personality in terms of the trait approach and outlined four different personality ‘factor’ models, and we discussed some of the similarities between them, for example, the common factors of extraversion and neuroticism. We noted how the trait approach has been criticised by some authors for being too general, and for its lack of power to discriminate how people behave over a diversity of situations and contexts. We also highlighted that people can sometimes behave in ways that differ from what the trait approach would suggest are their dominant traits, yet the trait approach is unable to account for this. Mischel (1968) offered an alternative explanation for these phenomena by suggesting that human beings are inconsistent in their behaviour and that it is the situations that the people find themselves in that are the best predictors of their behaviour. Counterarguments to this claim have led contemporary personality psychologists to adopt an interactionist approach in which behaviour can be explained by a confluence of situational and personality factors. In the last section, we set out the ways in which psychologists have applied personality theories and research to a real-world setting, such as the field of health, illness and wellbeing.