Increasing awareness of how individual motivation to learn language can fluctuate and change puts a premium on longitudinal research methods which can track learners over set periods of time. Revisiting previous research participants is one means of effecting this. This paper describes follow-up studies of an original research project in Indonesia and presents data showing the L2 motivational trajectories of nine participants over a decade. One major finding however was that the participants were influenced by taking part in the research. The paper re-analyses data from all stages of the research and identifies the main source of the influence to be the authority participants invest in the researcher, and the inspiration they draw from occasional contact with a foreigner. The findings therefore lend some support to the long-term motivating power of 'ought-to' and 'ideal' L2 selves. In highlighting researcher effects, the paper emphasizes the need for reflexivity in designing and carrying out longitudinal research, especially when interpreting interview data. The presence of possible negative effects on at least one participant also raises ethical issues for the selection of participants and their interaction with the researcher.