operandum

== English == === Etymology === From Latin operandum. Doublet of operand. === Noun === operandum (plural operanda) A lever, key or device installed in an operant chamber, upon which the "subject" exerts its responses. Sometimes referred to as a manipulandum. In the prototypical operant conditioning experiment, a rat (the subject) presses upon a lever (the operandum) which triggers the delivery of food (the reward or reinforcer). ==== Related terms ==== == Latin == === Participle === operandum inflection of operandus: nominative/accusative/vocative neuter singular accusative masculine singular