What have we stopped noticing?
The things we say, do, and accept without thinking twice.
Look closer where it comes from, what it assumes, and the case for keeping it
What you mean by it
To be the first to try something untested.
What it's actually picturing
The phrase points directly at animals used in laboratory testing. The figurative sense is recorded from 1920.
What it takes for granted
Being experimented on is treated as an ordinary, slightly comic role, for the animal and by analogy for you.
Worth knowing
Unlike most animal idioms, the practice it refers to is current rather than historical.
The case for keeping it
The speaker is usually volunteering themselves, so the joke is at their own expense.
Say it plainly
Go firstPilot it
Or have some fun
Be the test pilot
Where this comes from
- guinea pig · Online Etymology Dictionary