Question: What is a memory and how do we know what is what when we remember stuff?

Fiona McLean answered on 15 Jun 2014:

This is such a great question! I’m really glad you asked it. In fact this is the question I asked myself 3 years ago which has lead to me to my research that I do today.

The simplest definition of a memory is the retrieval, storage and recollection of information. So when you retrieve information you use your senses (sight, smell, hear, taste, touch and even your emotions) and your brain will encode this information. Different parts of the brain will encode information from different senses. The types of cells in the brain that do all this are called neurons. Your brain can pull information together and store it which then allows it to be retrieved at any time. For example if you eat a type of fruit and you see it is green and round and has a stalk coming out of it and in the middle there is a core with seeds- if you have had an apple before your brain will recognise what you’re eating as an apple. Your brain will also use your senses of smell and taste to confirm even more so that it is an apple.

There is however different types of memory and some are more complex than others. The 2 main types are short-term memory and long-term memory. Short-term memory would be something like remembering a list of items your teacher has given you to ask the teacher in the classroom next door for. Long-term memory would be something like remembering your 8th birthday party. Long-term memories tend to be more complex. For example at your 8th birthday party there will have been exciting food to taste and it perhaps was at a location that was new to you. You will also have probably been really happy. However a list of items from you teacher is a lot less stimulating (and you probably didn’t get cake!).

However short-term memories can be made into long-term memories. The part of the brain that converts short-term memory to long-term memory is called the ‘hippocampus’. The hippocampus is a really important part of the brain and is especially important for a type of memory called ‘episodic memory’. Episodic memory is a type of memory which includes ‘what’, ‘where’ and ‘when’ experiences together. For example an episodic memory would be in what room in your house you left your iPod and where about in that room you left it. It is in fact this type of memory which stops working in diseases which cause memory loss in older people (such as Alzheimer’s disease and Parkinson’s disease) and I am particularly interest in how it and the hippocampus in the brain work.

There is still a lot unknown about memory, the different types of memory and how they work. I think the brain is one of the organs in the human body which we still do not fully understand and this is why it is so interesting to study!

Thanks so much for your question-it was really good! My answer had quite a lot of information in it and I could have written pages and pages! I have actually explained to you some things which I have tried to explain to people who have been scientists for over 30 years (and sometimes they don’t understand it)! If there was anything that I didn’t explain clearly enough please tell me and I will try to explain it a bit more.