What is learning and memory?

Learning is defined as a relatively permanent and irreversible adaptive change in behavior. It always results from experience. The ability of an organism to store and recall the effects, sensations, and knowledge gained through learning and experience is called memory.

How learning is linked to memory?

Learning is essentially the acquisition of new behavioral patterns or information from past experiences in practice. Memory is a crucial mental activity without which humans would be limited to simple reflexes and stereotyped behaviors. As a result, learning and memory are some of the most extensively researched topics in neuroscience.

Learning and memory go hand in hand in general because learning without memory is useless. Learning entails changes in behavior, and the outcomes can only be put to use if they are saved in the brain and recalled as and when they are required. Memory is necessary for learning, but it is also dependent on learning because the information stored in one’s memory serves as the foundation for associating new knowledge.

Memory

Memory is a process of active, subjective, and cognitive reflection on our past experiences. Memory in the human brain is made up of three primary processes: encoding, storing and retrieving. In encoding, the content of the information that is learned is converted into a form that can be kept in memory. It involves the selection of useful information for storage.  The storing is a consolidation process, which involves stabilizing a memory trace after it has been acquired. In this process, the encoded content is kept in memory. In the retrieving stage, the brain retrieves the information that has been encoded and saved in the past. 

Different forms of memory

There are two main types of memories that can be classified based on physiological considerations, explicit and implicit memories. Explicit memory, also known as declarative or recognition memory, is always associated with awareness or consciousness. Implicit memory, also known as non-declarative memory, is a memory that occurs without the presence of consciousness or knowledge. Explicit memory is of two types - episodic and semantic. Episodic memory is the ability to explicitly recall the information about a particular event that occurred at a specific time in a specific place. The ability to consciously recall the knowledge of facts that are not related to a specific time and place is known as semantic memory.

Based on duration, memory is classified into short-term and long-term memory. The former is short-living, whereas the latter is long-lasting. Both of them operate as filters, protecting our brains from the massive amounts of data we are bombarded with on a daily basis.

Neuroscience behind memory formation and learning

In higher animals, learning and memory result from the activity of the nervous system in the brain. Learning and memory both are complex phenomena that involve nervous, physiological, and biochemical mechanisms.

The neurons regularly synthesize new memory proteins in the brain associated with learned behavior to modify components of the synapse, such as the receptors for these chemicals, through a process termed synaptic plasticity, allowing them to selectively reinforce their connections with one another. This results in the formation of a network of cells that jointly encode a memory. The stronger a memory's neural network gets, the more it is recalled. This more or less permanent record of information gained during learning exists somewhere in the neural system. It's known as an engram or a memory trace. The hippocampus and the highly specialized cerebral cortex of the brain are thought to be the sites of engram production and storage in higher mammals. Memory appears to be strongly linked to events occurring at synapses in the brain.

Learning

Learning can be considered as an adaptive change or modification in individual behavior as a result of experience. Certainly, it is an individual event, different for different individuals. Learned behavior is the most important type of animal behavior used mostly in neuroscience as a research topic, and it is best evolved in humans.

Types of learning

Non-associative learning

This is the mode of learning, developing without its association with any reinforcement (reward or punishment). It is of two types, namely habituation and sensitization.

(a) Habituation

In habituation, the repeated exposure of an animal to a stimulus, without punishment or reward, progressively decreases the probability of any response by the animal to that stimulus. So, it is learning not to respond or react to a stimulus, or to ignore insignificant stimuli. Habituation has a high adaptive value that enables animals to save energy by not responding to apparently insignificant stimuli. It is significant in that it makes the brain free from responding to insignificant stimuli while permitting it to concentrate on useful survival behavior.

(b) Sensitization

Sensitization is the increase in the probability of a response due to the repeated occurrence of a biologically significant stimulus. It is in direct contrast to habituation.

Associative learning

In associative learning, an animal establishes an association between a pair of stimuli, one of which initially evokes little or no response and the other one normally evokes a reflex response. So, the association is formed as a consequence of the presence of two stimuli. Ivan P. Pavlov was the first researcher in the study of associative learning.

Selective learning (trial and error learning)

Selective learning is also called instrumental learning. This is only observed in vertebrates. In this kind of learning, the animal learns after several trials and errors. The animal learns to eliminate a specific behavior that produces no reward, or produces a negative effect, and also to repeat a behavior that produces a positive effect. Trial and error learning is a common practice in our life. It is through this practice that we learn in childhood not to touch hot stoves and how to carry out many other highly coordinated activities. Edward Lee Thorndike introduced the study of trial and error learning.

Insight learning

In insight learning, an animal learns how to solve complex problems easily and immediately. This type of learning is rare in invertebrates, while it is common among mammals. It is mainly the province of humans and other primates. Human beings have the unique ability to solve problems with exceptional ease and amazing rapidity with the help of high levels of intelligence, high degrees of thinking, reasoning, analyzing, interpreting, and understanding powers, and acute memory. Insight learning is probably the highest form of learning. Wolfgang Kohler carried out the first research in the study of insight learning. 

Latent learning (exploratory learning)

In this learning behavior, an animal explores new circumstances and new surroundings and learns information that may be useful later on, but not immediately. It does not respond to a stimulus immediately but on a later occasion. So, it is a kind of pre-adaptation for life at a later stage. The acquired information remains hidden or unexpressed for some time for want of punishment or reward. It may be advantageous to the animal in the future. Latent learning enhances the fitness and survival value of organisms. The research on the study of latent learning was carried out by Edward Tolman.

Phase-Specific learning

This is a kind of learning connected to a specific and recognizable part or phase of the activity cycle. Imprinting, avian song learning, and language learning are examples. The zoologist Konrad Lorenz is a pioneer in the study of imprinting.

Context and Applications

This topic is significant in the study in ethology and in the exams of school, graduate, and post-graduate levels, especially for bachelors in zoology and masters in zoology.

Practice Problems

Question 1: The encoded form of memory is known as.........?

1. Synaptic plasticity

 2. Memory proteins

 3. Engram

4. None of the above

Answer: Option 3 is correct.

Explanation: The permanent record of memory exists in the neural system. It's known as an engram or a memory trace.

Question 2: An adaptive change or modification in individual behavior through experience is called ......?

1. Memory
2. Learning
3. Adaptation
4. None of the above

Answer: Option 2 is correct.

Explanation: Learning can be considered as an adaptive change or modification in individual behavior as a consequence of experience

Question 3: -------------- is regarded as the highest type of learning.

1. Habituation
2. Associative learning
3. Sensitization
4. Insight learning

Answer: Option 4 is correct.

Explanation: In insight learning, an animal learns how to solve complex problems easily and immediately. This is the highest form of learning and it is found in human beings.

Question 4: Which type of learning is a kind of pre-adaptation for life at a later stage?

1. Phase specific
2. Insight learning
3. Selective learning
4. Latent learning

Answer: Option 4 is correct.

Explanation: In latent learning, information is learned, which may be useful later on, but not immediately. So, it is a kind of pre-adaptation for life at a later stage. 

Question 5: Imprinting is an example of------------?

1. Habituation
2. Insight learning
3. Phase specific learning
4. Associative learning

Answer: Option 3 is correct.

Explanation: Imprinting, language learning, and avian song learning are examples of phase-specific learning.