What does experimenter mean?
An experimenter is a person who designs and carries out experiments — structured trials intended to test a hypothesis, observe a phenomenon, or discover something new. The word appears most often in scientific and academic contexts, where it typically denotes the researcher conducting a laboratory study, as opposed to the subjects or participants being studied. In psychology and the social sciences it has particular weight: the well-documented 'experimenter effect' refers to ways an experimenter's own expectations or behaviour can unintentionally influence results, making the term central to discussions of research bias. Outside the lab, experimenter can be used more loosely for anyone who tries new methods or approaches, such as an inventive cook or an artist testing techniques. The word derives from 'experiment', which traces back through Latin roots meaning to try or to test thoroughly. It is a neutral term carrying no inherent praise or criticism, though context may lend connotations of rigour or curiosity.
A person who conducts experiments, especially scientific ones.
"Each experimenter followed the same protocol to keep the study reproducible."
Often used in contrast to 'participant' or 'subject' in research settings.
A person who tries out new ideas, methods, or experiences.
"An incorrigible experimenter, he painted with coffee before switching to oils."
Standard plural; used when referring to multiple researchers or trial-makers.
"Experimenters at both universities replicated the finding independently."
In psychology, the 'experimenter effect' shows that even the person running a study can unconsciously bend the results — the observer becomes part of the experiment.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of experimenter
'Experimenter' is formed from the noun 'experiment' plus the agentive suffix '-er'. 'Experiment' entered English in the Middle Ages from Old French, ultimately deriving from Latin 'experiri', meaning 'to try or test', from the root 'peritus' meaning 'tested' or 'skilled'. The same Latin root gives English 'experience', 'expert', and 'empirical', all of which share the underlying idea of learning by trial rather than theory.
Related word forms
How experimenter is actually used
Neutral to formal register; common in academic and scientific writing, where it often refers specifically to the person administering a study. In psychology, 'the experimenter' can denote the researcher's role as distinct from participants.
Easily confused with experimenter
'Experimenter' is a person who runs experiments, while 'experiential' describes knowledge gained through direct personal experience.