Definition
A principle of learning which states that the first way a skill or piece of information is learned tends to be the strongest and most lasting impression, and is therefore the version the learner will return to under pressure. Because of this, instructors must teach correctly the first time, since unlearning a wrong initial impression is much harder than learning it right from the start.
Plain English
What you learn first sticks the hardest. If you learn it wrong the first time, that wrong version is what you'll fall back on later -- especially when you're stressed or rushed.
Context Anchor
Used in flight-instructor training when planning demonstrations, explanations, checklist use, radio calls, and any first exposure a student has to a skill.
Derivation
From Latin 'primus,' meaning 'first.' The principle is named for the special weight given to the first exposure to a subject -- the 'primary' learning event.
Why Pilots Care
An instructor who demonstrates or explains something incorrectly the first time creates habits that are difficult and time-consuming to correct later.
Analogy
It is like setting the first track in soft ground. Later steps tend to follow that same track, even if you try to walk a different path.
Intuition Check
Primacy does not mean “most important” in a general sense here. It means the first thing learned has extra staying power.
Example Sentence 1
Because of the principle of primacy, the instructor demonstrated the steep turn correctly before letting the student attempt it, knowing that a sloppy first attempt would be hard to correct later.
Example Sentence 2
Because of the principle of primacy, the student retained the proper engine-start checklist sequence taught during the initial ground lesson.