Memory occurs because of three processes: Encoding (transferring information from the environment into our brains through sight, sound, taste, touch or smell), storage (retaining that information) and retrieval (getting that information from where it is stored back into conscious awareness). There are also three types of memories: Sensory, short-term and long-term.
Sensory memory has the largest capacity for how much it can store, but it has a very brief retention. There are three types of sensory memory: Icon, echo and haptic. Icon memory is visual. The visual mental imagery you see is remembered for less than a second.
Echo is auditory. After you hear a fleeting sound, you can remember it for about four seconds. Haptic memory has to do with touch. This type of memory only lasts one second.
Short-term memory provides us the ability to remember certain items (on average, five to nine items). Your “items” don’t have to consist of just one thing, they can have more. For example, if you’re trying to remember the string 573903266928720381, you might find it’s easier to split the numbers into two-digit numbers: 57, 39, 03, 26, 69, 28, 72, 03, 81 — with each two-digit being an “item” — or, three-digit numbers to increase your chances of remembering it: 573, 903, 266, 928, 720, 381. You will find the two-digit and three-digit numbers are easier to remember than that first 18-number string.
Long-term memory is technically unlimited. It retains two types of memories: Declarative/explicit memories and non-declarative/implicit memories.
Declarative/explicit memories are comprised of episodic and semantic memories. Episodic memories are our personal experiences linked with specific times and places. Semantic memory is impersonal facts and everyday knowledge.
Non-declarative/implicit memories consist of procedural memory and emotional conditioning. Procedural memory is the ability to remember how to do something. Emotional conditioning is based on Ivan Palvov’s classical conditioning. In this context, it’s when you have an emotional response to something you technically shouldn’t.
Even though we have unlimited storage in our LTM, we don’t remember everything because it isn’t useful. We, as a species, are supposed to survive. Remembering the year George Washington became president (1789) doesn’t help us do this. So, even though we can’t remember everything, the things we do remember are things that our brain has decided are useful.
