experimenter

noun

1. A person who experiments.

   “In the request-only condition, the experimenter said simply 'Excuse me, I have 5 (20) copies. May I use the xerox machine?' In the placebic information condition, this was followed by the phrase 'because I need to make copies'. In the real information condition, the reason offered in support was 'because I am in a rush'.”

   “In reliable environments, waiting to eat a second marshmallow is likely to be beneficial. However, in environments in which rewards are uncertain, such as when experimenters are unreliable, eating the single marshmallow right away may be beneficial. Thus, impulsivity can be understood as an adaptive response to the contingencies present in an unstable environment rather than a moral failure in which animalistic drives overwhelm human rationality.”