Our memories are inextricably linked with our identities—from memory of a childhood home or pet to remembering the address of a favourite restaurant.

There are several different types of memories, some of which are fleeting, and others that last a lifetime. Normally, when we talk about memory or remembering things, we are referring to explicit memory, which is consciously recalled. Explicit memories can be episodic, meaning that they relate to experiences or 'episodes' in your life (e.g., a particular holiday or the first time you were stung by a bee); or, they are semantic, relating to facts or general knowledge (e.g., that the brain has about 90 billion neurons). Explicit memories are clearly affected by neurodegenerative diseases such as Alzheimer’s disease.

memory diagram

Long-term memory

As seen in the diagram above, explicit memory is one type of long-term memory. The other kind of long-term memory is implicit, or unconscious memory. These unconscious memories may be procedural, involving learned motor skills—learning how to ride a bike or how to type using a keyboard, for example.

Implicit memories can also result from priming, which occurs when exposure to one stimulus influences your brain’s response to another. For example, in word-judging tasks, participants identify pairs of associated words such as BREAD–BUTTER faster than non-associated pairs such as BREAD–DOCTOR.

Short-term memory

Short-term memory enables the brain to remember a small amount of information for a short period of time. The shortest type of memory is known as working memory, which can last just seconds. This is what we use to hold information in our head while we engage in other cognitive processes. An example is remembering the numbers a new friend recites as you navigate your phone’s menu system to add a contact. A person’s working memory capability is one of the best predictors of general intelligence, as measured by standard psychological tests.