"individual differences" is a narrow category only used to describe the "big five" personality attributes.

This statement is false.
Individual differences consists a broad category which describes the characteristics that describe and differentiate every person. Individual differences refer to a vast number of differences which could include intelligence, motivation, personality, abilities, self-concept and self-esteem. On the other hand, big five personality traits is a model which suggests five factors commonly used to describe the human behaviour and personality. These five trait dimensions are openness to experience, conscientiousness, extraversion, agreeableness and neuroticism.