interference

Meaning: Interference is forgetting that occurs when other learned material competes with a memory and makes it harder to retrieve, even if the memory is still stored. It is stronger when the items are similar. Proactive interference: older information disrupts learning or recall of new information. Retroactive interference: newer information disrupts recall of older information. (Physics uses the word for overlapping waves, which is unrelated.)

On the MCAT: A passage has participants learn list A, then list B, then tests recall. Poor recall of B points to proactive interference; poor recall of A points to retroactive interference. Everyday examples: an old locker combination intruding on a new one (proactive), or a new phone number blurring the old one (retroactive). Expect to predict that greater similarity between the two sets increases interference, or to pick the control group that learned only one list.

Common confusion: Students swap the names. Pro means forward: old material acts forward on new learning. Retro means backward: new material acts back on old memories. Also, interference is one account of forgetting alongside decay and retrieval failure, and it is not the same as anterograde or retrograde amnesia, which follow brain injury.