Long-term memory (LTM) is the system for continuous and permanent storage of information, characterized by a practically limitless capacity. It holds memories for extended periods, from minutes to a lifetime. Fundamentally, LTM is divided into two main categories: implicit memory, which is unconscious, and explicit memory, which involves conscious recall. Information within LTM is typically organized into complex, structured networks.

Long-Term Memory (LTM)

Sensory memory refers to the storage of brief sensory events, including auditory, visual, and gustatory stimuli. This form of memory is characterized by its very short duration, typically lasting for up to a couple of seconds.

Sensory Memory

Short-term memory (STM) serves as a temporary storage system that processes incoming information from sensory memory. It is capable of retaining a limited amount of data for a brief duration of 15 to 30 seconds. While in this active state, short-term memory can also integrate new sensory input with existing knowledge retrieved from long-term memory. Although often confused with working memory, short-term memory is more accurately classified as a distinct sub-component within the broader working memory framework.

Short-term Memory (STM)

A chef is demonstrating how to perfectly chop an onion. Without conscious thought, she executes a series of precise, rapid knife movements that she has perfected over many years of practice. Which type of memory is the chef primarily relying on to perform this well-rehearsed physical skill?

* Sensory memory
* Short-term memory
* Long-term memory
  * Implicit (Non-Declerative)
    * Semantic memory
    * Episodic memory
  * Explicit (Declerative)
    * Procedural memory
    * Associative memory
    * Non-associative memory
    * Priming

Columbia University

Syracuse University

Washtenaw Community College

Google

The study of memory revolves around several key inquiries: How is information processed and stored? What are the different types of memory and their characteristics? What are the mechanisms for retrieving stored information? And what causes the loss of memories, or forgetting? These questions guide the exploration of memory functions.

Fundamental Questions in Memory Research

Memory can be defined as the system or process responsible for storing learned information so that it can be utilized at a later time.

Definition of Memory

Breedlove, S. & Watson, N. (2017). Behavioral neuroscience, eighth edition. Oxford University Press.

Behavioral Neuroscience 8th Edition

Spielman, R. M., Jenkins, W. J., & Lovett, M. D. (2020, April 22). Psychology (2nd ed.). OpenStax. https://openstax.org/books/psychology-2e/pages/1-introduction

OpenStax Psychology (2nd ed.) Textbook

Memory operates through three fundamental processes that occur in a specific sequence: encoding, followed by storage, and finally retrieval. This flow is often visualized as a linear progression, where information must be encoded before it can be stored, and stored before it can be retrieved.

Processes Involved in Memory

Types of Memory

Forgetting is defined as the loss of information from long-term memory. This is a universal human experience, manifesting in everyday situations like forgetting a name, a birthday, or the location of personal items like car keys. Such memory failures, while common, can be a source of frustration and embarrassment, underscoring the fragile nature of human memory.

Forgetting

A researcher conducts a study where one group of participants is asked to memorize a list of words by silently repeating them, while another group is asked to create a vivid mental image for each word. Later, both groups are tested on their recall of the list. This experimental design is best suited to investigate which of the following fundamental questions about memory?

Gene RbAp48 synthesizes protein RbAp48, which is part of a group of proteins in the brain known as the CREB complex. These proteins are an important part of turning on the gene expression necessary for  converting short-term memory to long-term memory.

Gene RbAp48

Human memory is not a perfect recording device; it is flexible and susceptible to numerous errors. These inaccuracies can lead to feelings of frustration or embarrassment and have significant real-world consequences, such as the demonstrated unreliability of eyewitness testimony in legal contexts.

Problems with Memory

Refer to a way or technique that facilitates the transfer of information from short-term to long-term memory.

Memory-Enhancing Strategy

There have been a number of psychologists who have contributed to the study of memory. These include:
- Karl Lashley
- Hermann Ebbinghaus 

Important Figures in Memory Research

A hypothetical scenario illustrating the critical role of memory in daily life involves imagining a day without any retained knowledge. In this state, fundamental tasks such as getting dressed would be impossible, as one would not recall how to use buttons or zippers. Simple personal hygiene like brushing teeth or tying shoes would need to be relearned. Furthermore, the ability to recognize familiar faces, one's own home, or even the concept of basic objects like a bed would be lost. Essential survival activities, like finding and preparing food, would become insurmountable challenges, demonstrating that memory is foundational to personal identity, autonomy, and basic functioning.

Hypothetical Scenario of Life Without Memory

The framework for understanding memory often involves viewing it as an information processing system, which draws a parallel to the functioning of a computer. This analogy helps in conceptualizing how information is systematically encoded, stored, and retrieved by the brain.

Memory as an Information Processing System

An engram is the theoretical physical trace or representation of a memory within the brain. Early researchers like Karl Lashley did not find evidence of the engram, which led him to formulate the equipotentiality hypothesis. However, modern psychologists are making progress in locating these physical memory traces, particularly by investigating the role of synapses in neural circuits.

Engram

In contrast to the idea that memory is distributed throughout the entire brain, modern scientific understanding posits that memory functions are localized. This means that specific parts of the brain, and even particular neurons within those areas, are primarily responsible for forming and storing memories. This view gained traction through research conducted after Karl Lashley's initial explorations.

Localization of Memory

Contrary to the earlier belief that memory involves the entire brain, research following Lashley's work has demonstrated that memory functions are localized. Specific brain regions and even individual neurons play key roles in forming memories. The primary structures identified as crucial for memory are the amygdala, the hippocampus, the cerebellum, and the prefrontal cortex.

Learn Before

Related

Learn After