There are two main theoretical approaches to studying motivation in second language acquisition - the social psychological approach and the cognitive approach. The social psychological approach examines integrative motivation and instrumental motivation, and was pioneered by Robert Gardner through numerous empirical studies. It uses self-report questionnaire data correlated with language test performance. The cognitive approach examines intrinsic and extrinsic motivation and has studied Chinese students in the UK who were mainly extrinsically motivated to improve their careers. Both approaches aim to understand how individual differences in motivation influence outcomes in language learning.