Serial position effect
We remember the first and last items in a sequence best, and the middle worst.
What it means
The serial position effect is the finding that, when recalling a sequence, people remember items from the beginning (the primacy effect) and the end (the recency effect) better than items in the middle, producing a characteristic U-shaped recall curve. The two ends are explained by different mechanisms: primacy arises because early items receive more rehearsal and are more likely to be consolidated into long-term memory, while recency arises because the final items are still held in short-term or working memory at the moment of recall. A telling piece of evidence is that delaying recall or adding an interfering task selectively wipes out the recency portion while leaving primacy intact, since the late items are flushed from the short-term store. The middle items suffer because they get neither extra rehearsal nor the benefit of recency. The effect shapes how people remember lists, arguments, candidates, and product line-ups, and it interacts with the peak–end rule for evaluations over time. It matters because order is a free design variable: placing the most important information first or last, and avoiding burying it in the middle, measurably improves what audiences retain.
Examples
Reciting a grocery list from memory, you reliably nail the first and last items and forget the ones stuck in the middle.
A panel interviewing eight candidates in one day argues mostly about the first and the last; the ones seen just after lunch have to be looked up in the notes.
In a ten-slide deck, the key point buried on slide six is the one nobody quotes afterwards. Move it to the opening or the close and it survives the meeting.
First described in Ebbinghaus; Murdock (1962).