Autonomy is widely regarded as a central value in research ethics. Respect for persons in research ethics is generally seen as largely involving respect for research subjects' autonomous decisions, and informed consent guidelines are seen a geared towards the protection and promotion of autonomy. I argue that this focus on autonomy in research ethics is misguided; it does not form a good expression of respect for persons or a good basis for informed consent guidelines in research. I suggest that respect for persons in research ethics is better construed as involving respect for the choices people have reason to value, as well as protection of individual wellbeing. Though these two values seem likely to clash, I argue that properly structured informed consent requirements can protect and promote both these values in the context of research ethics with minimal conflict. Using a Lockean account of personal identity, I single out a subset of decisions in research ethics for which autonomy forms an important means of assessment, and argue that the appeal to autonomy has a special function in these cases. That is, a Lockean theory of personhood can be used to establish the agent's authority over making a decision on behalf of her distant future self, against intersubjective scrutiny. Though this is a crucial means of evaluating some decisions in research, it will only be relevant in a relatively small number of cases.