Discovered by Hermann Ebbinghaus and later formalized by modern memory researchers.
Describes how the position of an item in a sequence affects its likelihood of being recalled.
Primacy effect: early items are remembered better due to more rehearsal time.
Recency effect: late items are remembered better because they are still in short-term memory.
Items in the middle are most likely to be forgotten.
This effect creates a U-shaped curve when recall probability is plotted against position.
Describes how information is lost over time when there is no attempt to retain it.
The curve shows a steep drop in memory shortly after learning, then a slower decline.
After about 20 minutes, around 40% of new information is forgotten.
After one day, more than 60% can be lost without review.
The curve flattens over time—what is retained tends to stay longer.
Regular review or reinforcement can drastically reduce forgetting.