Humans have different types of memories for different lengths of time. Short-term memories last seconds to hours, while long-term memories last for years.
We also have a working memory, which lets us keep something in our minds for a limited time by repeating it. Whenever you say a phone number to yourself over and over to remember it, you are using your working memory.
Another way to categorise memories is by the subject of the memory itself, and whether you are aware of it. Declarative memory, also called explicit memory, consists of the sorts of memories you experience consciously. Some of these memories are facts, others consist of past events you have experienced, such as a childhood birthday.
• ls it easy for you to remember names or telephone numbers?
• Do you find it easy to match new friends' faces to their names?
Non-declarative memory, also called implicit memory, unconsciously builds up. This includes procedural memories, which your body uses to remember the skills you have learned.
Do you play an instrument or ride a bicycle?
Those are your procedural memories at work.
Non-declarative memories can also shape your body’s involuntary responses, like salivating at the sight of your favourite food or being nervous when you see something you fear1.
1 Emotions "attach themselves" to new information in the brain, acting as an indicator of importance. The stronger the intensity, the more clearly and readily you are able to remember that memory.
In general, declarative memories are easier to form than non-declarative memories.
It takes less time to memorise a country’s capital than it does to learn how to play the violin, but non-declarative memories remain more easily.
Once you have learned to ride a bicycle, you do not forget.
To understand how we remember things, neuroscientists study amnesia, the loss of memories or the ability to learn. Amnesia is usually the result of some kind of trauma to the brain, such as a head injury, a stroke, a brain tumour, or chronic alcoholism.
There are two main types of amnesia.
The first, retrograde amnesia, occurs when you forget things you knew before the brain trauma.
Anterograde amnesia is when brain trauma stops someone’s ability to form new memories.1
1 In some cases, hypnosis can help people overcome amnesia and regain ......