Information processing model: Sensory, working, and long term memory | MCAT | Khan Academy

Overview of Memory Processing

  • The brain processes vast amounts of information received from the environment.

  • Models of memory, particularly the information-processing model, compare the brain to a computer's function.

Information-Processing Model

  • Proposes that the brain's function includes:

    • Input from sensory information.

    • Processing of this information.

    • Outputting decisions and responses.

  • The model serves as a conceptual guide rather than a detailed map of brain activity.

Stages of Memory

1. Sensory Memory

  • Also called the sensory register.

  • First stage where sensory input is temporarily held.

  • Focuses mainly on two senses: sight and sound.

Types of Sensory Memory

  • Iconic Memory: Memory for visual stimuli, lasts less than 0.5 seconds.

  • Echoic Memory: Memory for auditory stimuli, lasts for 3-4 seconds.

  • Example: Echoic memory enables recall of recent parts of a conversation.

2. Working Memory

  • Also known as short-term memory but referred to as working memory by psychologists.

  • Processes information that is currently being thought about.

  • Capacity of working memory:

    • Approximately 7 ± 2 pieces of information (magic number seven).

    • Variation based on complexity and age.

  • Historical context of phone numbers: Originally seven digits for optimal recall.

Components of Working Memory

  • Visuo-Spatial Sketchpad: Processes visual and spatial information (e.g., images, maps).

  • Phonological Loop: Processes verbal and auditory information (e.g., numbers and words heard).

    • Example: Repeating a phone number to remember it.

  • Central Executive: Directs and coordinates activities of other components in working memory.

    • Acts like a traffic cop to manage tasks that require multiple forms of input.

  • Episodic Buffer: Integrates and stores information from different components, linking to long-term memory.

Long-Term Memory

  • Final stage in the information processing model, akin to saving files on a computer.

  • Long-term memory has greater capacity and stores information for extended periods.

Types of Long-Term Memory

Explicit Memory (Declarative)

  • Memory that can be consciously recalled:

    • Semantic Memory: Facts and general knowledge (e.g., vocabulary).

    • Episodic Memory: Personal experiences and events (e.g., memories of birthdays).

Implicit Memory (Non-declarative)

  • Memory that is not consciously accessible:

    • Procedural Memory: Skills and tasks (e.g., riding a bike).

    • Priming: Previous exposure influences interpretation (e.g., associations made from seeing related images).

Memory Capacity

  • Long-term memory capacity is theoretically unlimited.

  • Unlike computers, human memory does not get "full"; it can continuously store information.