Discussions about memories have always been intriguing. Science defines memory as the psychological process of acquiring, storing, retaining, and retrieving information. The brain plays an important role in the formation of memories. Depending upon the purpose and use of information, the memories are categorised under different heads. Read through to know all about memories.
Types of Memories
Memories define our identity. They are inextricably linked to our existence. Depending upon their duration, purpose, and use, human memories fall into smaller sub-sections. They are broadly classified into four categories:
- Sensory memory
- Short-term memory
- Working memory
- Long-term memory
1. Sensory Memory
Sensory memory is the one which enables us to remember sensory information even after the stimulation ceases to exist. These are the shortest memories and are linked to touch, sound, and sight. But when the same sensory experience recurs, the brain begins to remember/ attach similar previous memories. This slowly converts sensory memory into short-term and subsequently long-term memory.
- Sensory memory obtained through sight/ visual sensory impression is the iconic memory
- Sensory memory obtained through hearing is the echoic memory
- Sensory memory obtained through touch is haptic memory
2. Short-Term Memory
Short-term memory enables us to retrieve information about specific events and instances. It is not a fleeting memory like sensory memory, nor is it permanent like long-term memory. The memory can be retrieved for brief periods and is also known as the primary or active memory.
According to studies, short-term memory can last up to 30 seconds. However, rehearsing short-term information several times converts short-term memory into long-term memory.
3. Working Memory
The type of memory that involves a small amount of information to be recalled immediately to perform cognitive tasks is known as working memory. Working memory can be both short-term memory and long-term memory. It can also be used interchangeably.
4. Long-term Memory
A majority of our memories are long-term. Recalling anything that happened in the past is a long-term memory. Our memory’s ability to hold information is limitless.
Long-term memory can further be divided into two sub-categories:
- Explicit Long-Term Memory – These are the memories that are formed consciously and deliberately. These can be episodic or semantic. Episodic memories are formed from different stages and milestones of life. On the other hand, semantic memories are facts and information collected over the years.
- Implicit Long-Term Memory – These memories are formed unconsciously but affect the way a person feels, behaves and thinks. These can be priming or procedural memories. Priming memory happens when exposure to one stimulus helps identify the associated one. On the other hand, procedural memory involves motor skills.
Roles of Different Types of Memories
Each memory is important. Every type of memory has a different role and function to play. It also affects our personality and plays a crucial role in how we respond to situations. It is also important for decision-making.
Short-term memory allows easy and instant comprehension of information. For instance, reading a book or watching a movie involves short-term memory.
On the other hand, long-term memory reflects your identity and existence. It facilitates how you walk, talk, or engage in daily activities. It plays an important role in your academic achievements and enables you to recall important facts and dates. How you conduct yourself daily is also facilitated by your long-term memory.
How are Memories Made?
Memories are formed through complex and intricate tasks. Every stimulation that the brain receives is carefully transformed into a memory. Brain studies reveal that the formation of memories occurs in stages. These include:
- Encode
- Store
- Recall
Encode – The process of memory-making begins with encoding. The brain receives external information and stimuli through its five senses – touch, hearing, vision, smell, and taste. This sensory register process happens only for a few seconds and the information is passed on for storage.
Store – As the sensory information passes on to the brain, it stores information temporarily so that it can be recalled again.
Recall – Rehearsing the stored information again and again converts it into long-term memory. Once the information gets transformed into a long-term memory, it stays in the brain for an extended time, at times for as long as a lifetime.
About Memories: Where are They Stored?
The brain stores memories by changing the way the neurons communicate with each other. This communication link is strongest in long-term memories. Different types of memories are stored in different brain parts. As different regions of the brain are interconnected, this allows a seamless flow of information.
Six different regions of the brain are involved in the storage of memories. These are:
- Short-term and working memory are stored in the prefrontal cortex.
- Long-term explicit memories are stored in the hippocampus, the neocortex and the amygdala.
- Long-term implicit memories are stored in the basal ganglia and cerebellum.
Brain Parts Involved in the Storage of Memory
The different brain parts involved in the storage of memory are:
- Hippocampus – It is located in the brain’s temporal lobe. It helps in the formation of episodic memories and allows easy indexing for subsequent access.
- Neocortex – It is the major portion of the cerebral cortex, the thin sheet that gives a wrinkly effect to the human brain. It is involved in sensory perception and motor skills.
- Amygdala – It is the almond-shaped structure located in the brain’s temporal lobe. It is responsible for strong emotional memories.
- Basal Ganglia – It lies deep within the brain and is responsible for habit formation and learning.
- Cerebellum – it is located at the rare base of the brain. It is responsible for fine motor skills.
- Prefrontal Cortex – it’s the portion located at the front of the brain. It plays a crucial role in complex cognitive functions.
Forgetfulness and Erosion of Memory
Forgetting is not being able to recall the encoded and stored memory. This can be because of inattentiveness or when the brain fails to recall the stored information. The latter, also known as erosion of memory, can be due to two reasons. These are:
- Decaying theory – If a certain memory is not rehearsed enough, it will eventually be lost. Furthermore, the natural ageing process causes damage to the hippocampus, temporal lobe, and other brain parts.
- Interference theory – This happens when new information replaces old information. Thus, the brain forgets the old information.
Can We Improve Memory?
Thanks to the remarkable qualities of the brain, the improvement of memory can happen just as quickly as decaying. The tips to improve memory include:
- Adopt good habits – A healthy lifestyle with good eating habits is paramount for a healthy brain. So, eat well, exercise regularly and sleep well to improve memory.
- Exercise the brain – While physical exercise is important for the brain and body, make sure to include brain exercises as well. Puzzles, crosswords and mind games help improve brain strength.
- Remain mentally alert – Read, write, and learn things every day.
- Avoid multitasking – Carrying out different tasks simultaneously forces the brain to switch focus. This divides attention and reduces overall brain effectiveness.
- Remove distractions – Any distractions in the environment reduces mental ability. Make sure your environment is work-conducive.
- Remain time bound – Stick to time limits and complete tasks within the stipulated time.
- Self-test – After having rehearsed enough, put yourself under the scanner and try to recall whatever learnt. A self-test is the best way to recall stored memory.
Conclusion
The human brain functions in a complex manner. One of the key brain functions is the formation and storage of memory. Encoding, storing, and recalling – the three stages of memory formation happen in different parts of the brain. The communication within the neurons further strengthens memories. From sensory memory, working memory, and short-term memory to long-term memory, every stimulus that the brain receives is transformed into one of the four types of memories. Knowledge about memories, and how they are formed and stored can help understand key aspects of behaviour and emotions. After all, it’s our memories that shape our identity.
Frequently Asked Questions About Memories
Q. How are memories formed?
The way the neurons communicate with each other helps in the formation of memories. Memories form when specific groups of neurons are activated and reactivated repetitively.
Q. Where exactly is the hippocampus located in the brain?
The hippocampus is one of the brain parts responsible for memory encoding. It is located deep within the brain, hidden under the medial part of the temporal lobe.
Q. Which part of the brain is responsible for storing memories?
While the hippocampus is one of the key brain parts responsible for the storage of memories, not all memories are stored in it. Long-term explicit memories are stored in the hippocampus. Long-term implicit memories are stored in the basal ganglia and cerebellum. Whereas, short-term and working memory is stored in the prefrontal cortex.
