Memory encoding allows information to be converted into a construct that is stored in the brain indefinitely. Once it is encoded, it can be recalled from either short- or long-term memory. At a very basic level, memory encoding is like hitting “Save” on a computer file. Once a file is saved, it can be retrieved as long as the hard drive is undamaged. “Recall” refers to retrieving previously encoded information.

The process of encoding begins with perception, which is the identification, organization, and interpretation of any sensory information in order to understand it within the context of a particular environment. Stimuli are perceived by the senses, and related signals travel to the thalamus of the human brain, where they are synthesized into one experience. The hippocampus then analyzes this experience and decides if it is worth committing to long-term memory.

Encoding is achieved using chemicals and electric impulses within the brain. Neural pathways, or connections between neurons (brain cells), are formed or strengthened through a process called long-term potentiation, which alters the flow of information within the brain. In other words, as a person experiences novel events or sensations, the brain “rewires” itself in order to store those new experiences in memory.

The four primary types of encoding are visual, acoustic, elaborative, and semantic.

Visual encoding is the process of encoding images and visual sensory information. The creation of mental pictures is one way people use visual encoding. This type of information is temporarily stored in iconic memory and then is moved to long-term memory for storage. The amygdala plays a large role in the visual encoding of memories.

Acoustic encoding is the use of auditory stimuli or hearing to implant memories. This is aided by what is known as the phonological loop. The phonological loop is a process by which sounds are sub-vocally rehearsed (or “said in your mind over and over”) in order to be remembered.

Elaborative encoding uses information that is already known and relates it to the new information being experienced. The nature of a new memory becomes dependent as much on previous information as it does on the new information. Studies have shown that the long-term retention of information is greatly improved through the use of elaborative encoding.

Semantic encoding involves the use of sensory input that has a specific meaning or can be applied to a context. Chunking and mnemonics aid in semantic encoding; sometimes, deep processing and optimal retrieval occurs. For example, you might remember a particular phone number based on a person’s name or a particular food by its color.

Not all information is encoded equally well. Think again about hitting “Save” on a computer file. Did you save it into the right folder? Was the file complete when you saved it? Will you be able to find it later? At a basic level, the process of encoding faces similar challenges: if the information is improperly coded, the recall will later be more challenging. The process of encoding memories in the brain can be optimized in a variety of ways, including mnemonics, chunking, and state-dependent learning.

Mnemonic devices are one way to help encode simple material into memory. A mnemonic is any organization technique that can be used to help remember something. One example is a peg-word system, in which the person “pegs” or associates the items to be remembered with other easy-to-remember items. An example of this is “King Phillip Came Over For Good Soup,” a peg-word sentence for remembering the order of taxonomic categories in biology.

Chunking is the process of organizing parts of objects into meaningful wholes. The whole is then remembered as a unit instead of individual parts. Examples of chunking include remembering phone numbers (a series of individual numbers separated by dashes) or words (a series of individual letters).

State-dependent learning is when a person remembers information based on the state of mind (or mood) they are in when they learn it. Retrieval cues are a large part of state-dependent learning. For example, if a person listened to a particular song while learning certain concepts, playing that song is likely to cue up the concepts learned. Smells, sounds, or place of learning can also be part of state-dependent learning.

Memory consolidation is a category of processes that stabilize a memory trace after its initial acquisition. Like encoding, consolidation influences whether the memory of an event is accessible after the fact. However, encoding is more influenced by attention and conscious effort to remember things, while the processes involved in consolidation tend to be unconscious and happen at the cellular or neurological level. Generally, encoding takes focus, while consolidation is more of a biological process. Consolidation even happens while we sleep.

Research indicates that sleep is of paramount importance for the brain to consolidate information into accessible memories. While we sleep, the brain analyzes, categorizes, and discards recent memories. One useful memory-enhancement technique is to use an audio recording of the information you want to remember and play it while you are trying to go to sleep.

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