Thus, while motivation can be seen as a primarily psychological construct,[11] investment is framed within a sociological framework, and seeks to make a meaningful connection between a learner’s desire and commitment to learn a language, and their complex identity. The construct of investment has sparked considerable interest and research in the field.[12][13][14][15][16][17][18] Darvin and Norton's (2015) model of investment in language learning locates investment at the intersection of identity, capital, and ideology. Responding to conditions of mobility and fluidity that characterize the 21st century, the model highlights how learners are able to move across online and offline spaces, performing multiple identities while negotiating different forms of capital.[19]