Implicit Memory
Overview
Implicit memory is a type of long-term memory that is not consciously controlled. It is also referred to as non-declarative memory, as individuals are not able to verbally declare or describe the information. This type of memory is primarily used for skills and habits, such as riding a bike or typing on a keyboard. Implicit memory is one of the two main types of long-term human memory, the other being explicit memory, which is memory that is consciously controlled.
Types of Implicit Memory
There are several types of implicit memory, each involving different parts of the brain and serving different functions. These include procedural memory, priming, classical conditioning, and habituation.
Procedural Memory
Procedural memory is a type of implicit memory that involves the ability to remember how to perform different actions and skills. This type of memory is often used for motor skills, such as riding a bike or tying a shoelace. Procedural memory is stored in the basal ganglia, cerebellum, and motor cortex of the brain.
Priming
Priming is another type of implicit memory that involves the influence of a previously presented stimulus on a response to a later stimulus. For example, if a person is shown the word "yellow" and is later asked to list fruits, they are more likely to list "banana" than if they had not seen the word "yellow". Priming is believed to be stored in the neocortex of the brain.
Classical Conditioning
Classical conditioning is a type of implicit memory that involves learning to associate two different stimuli. This type of memory was famously demonstrated by Ivan Pavlov in his experiments with dogs, where he conditioned the dogs to salivate at the sound of a bell by associating it with food. Classical conditioning is believed to be stored in the amygdala and cerebellum of the brain.
Habituation
Habituation is the simplest form of implicit memory and involves learning to ignore a stimulus that is repeated over time. For example, if a person lives near a train track, they may initially be disturbed by the noise of the trains but over time they will become used to it and may not even notice it. Habituation is believed to be stored in the spinal cord and the reticular formation of the brain.
Implicit Memory and the Brain
Implicit memory is stored and processed in various parts of the brain, depending on the type of memory. As mentioned above, procedural memory is stored in the basal ganglia, cerebellum, and motor cortex; priming is stored in the neocortex; classical conditioning is stored in the amygdala and cerebellum; and habituation is stored in the spinal cord and reticular formation.
The hippocampus, a structure located in the medial temporal lobe of the brain, is also involved in implicit memory. While the hippocampus is primarily associated with explicit memory, research has shown that it also plays a role in certain types of implicit memory, particularly in the initial stages of learning a new skill.
Implicit Memory in Everyday Life
Implicit memory plays a crucial role in our everyday lives, allowing us to perform many tasks without conscious thought. For example, we use procedural memory when we ride a bike, drive a car, or type on a keyboard. We use priming when we are influenced by a previous stimulus, such as when we are more likely to think of a word after seeing a related word. We use classical conditioning when we learn to associate two stimuli, such as when we come to associate the sound of a bell with the end of a class period. And we use habituation when we learn to ignore a repeated stimulus, such as the sound of a ticking clock.
Research on Implicit Memory
Research on implicit memory has provided valuable insights into how memory works and how it is affected by various conditions and disorders. For example, studies have shown that individuals with amnesia often retain their implicit memories, even though they may have lost their explicit memories. This finding has led to the understanding that implicit and explicit memory are governed by different brain systems.
Research has also shown that implicit memory can be influenced by a variety of factors, including age, stress, and drugs. For example, research has found that implicit memory tends to decline less with age than explicit memory, suggesting that different types of memory may age at different rates. Studies have also found that stress can impair implicit memory, while certain drugs can enhance it.