Ascientist, conducting a research study on sleep and learning, questions her own objectivity and decides to let a third person, not associated with the experiment, score the tests. the scientist is probably trying to eliminate

The scientist is probably trying to eliminate "experimenter bias".

In research, an experimenter bias, otherwise called research bias, happens when an analyst unknowingly influences results, information, or a member in a test because of abstract impact. It is troublesome for people to be altogether target which isn't being affected by close to home feelings, wants, or predispositions.  

Experimenter bias can happen at any period of the exploration procedure from the underlying foundation research to the last review of results. It is essential to consider experimenter predisposition as a conceivable issue in any examination setting. Steps can be taken to diminish the probability of its event, for example, leading visually impaired investigations and discovering non-one-sided information authorities.