Blocking is a phenomenon where a person is temporarily unable to recall a known piece of information, even though it feels just out of reach. A classic example is the “tip-of-the-tongue” experience—knowing a word but being unable to say it.
In memory research, blocking happens when other similar memories compete with the one we want, essentially “blocking” retrieval. Stress or fatigue can intensify this effect.
Although frustrating, blocking is a regular part of memory function. It shows that memory is not like a perfectly organised filing cabinet but more like a network where retrieval sometimes gets stuck. Usually, the blocked memory resurfaces later—often when we stop trying so hard.