The trait approach to personality is concerned with the description and characterisation of the basic components of personality. It attempts to identify primary characteristics by discovering the ‘building blocks’ of personality. A trait is a relatively enduring attribute or quality on which one individual differs from another. These traits include a range of possible behaviours activated according to the demands of the situation. For example, a sociable person is expected to be cooperative and friendly. Gordon Allport, the pioneer of this approach, proposed that individuals possess dynamic traits that determine behaviour across different situations.

The type approach and trait approach differ in their comprehension of personality. The type approach examines broad patterns in observed behavioural characteristics, placing individuals into specific categories or "types" based on similarity to that pattern. In contrast, the trait approach focuses on specific psychological attributes along which individuals differ in consistent and stable ways. Instead of categorising people, it rates them on the degree of presence or absence of a behavioural quality, such as "shyness" or "friendliness".

Furthermore, personality typologies in the type approach are often too simplistic. Human behaviour is highly complex and variable, making it difficult to assign people to a particular personality type. People do not fit neatly into simple categorisation schemes, which is why the trait approach provides a more nuanced understanding of individual differences.