Primacy effect
The primacy effect is the tendency to remember the first things in a list or session better than the ones in the middle. The start sticks because your brain has more time and focus to lock it in before the rest piles up.
When you take in a list of things one by one, the first few get more attention. You think about them, repeat them, and they have time to move into long-term memory. The items that come later have to compete with everything already in your head, so they fade faster.
This is one half of the serial position effect. The first items stick because of the primacy effect, and the last items stick because they are still fresh. The stuff in the middle is what usually gets lost.
It matters for studying because the start of a lecture or a study session often lands better than the rest. If you only ever start at the top of your notes, the same early pages get strong and the later ones stay weak.
Maria reads her biology notes in the same order every time. She always knows the first two pages cold, but the topics halfway through keep tripping her up on tests. Once she started shuffling where she begins, the weak middle parts finally started to stick.