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

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 approximately 86 billion neurons). Explicit memories are clearly affected by neurodegenerative diseases such as Alzheimer’s disease.

Memory is classified as being either short- or long-term, and long-term memory is either explicit or implicit. (Image: Nick Valmas / QBI)

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 are two examples.

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. It’s what allows you to temporarily remember a phone number for a few moments before you write it down, or a street name before you look it up.

Short-term memory is sometimes also referred to as working memory, but these two forms are actually slightly different. In short-term memory, the remembered information is not manipulated or organised, whereas this does occur in working memory. In addition, short-term and working memory also rely on distinct areas in the brain.