Memory and Memory Formation

Biological Foundations of Memory

  • Memory is the process by which the mind acquires, encodes, stores, and uses information, supporting all higher-level mental functions.

  • Hippocampus: A limbic system structure that assists in the formation and organization of new memories.

  • Neurons: Learning creates new connections through the branching of dendrites and axons.

  • Cerebral Cortex: The outer layer of the brain where specific areas are responsible for different memory types.

Sensory Memory

  • Sensory memory provides brief, unconscious copies of environmental stimuli.

  • Iconic Memory: Visual and sight-based sensory information.

  • Echoic Memory: Auditory and hearing-based sensory information lasting only a few seconds.

Stages of Memory Formation

  1. Encoding: Transforming sensory input into a form that the brain can remember.

  2. Storage: Retaining information for later use in either short-term or long-term systems.

  3. Retrieval: Recovering stored information for active use.

Short-Term and Working Memory

  • Short-Term Memory: A system for temporary storage of small amounts of information under conscious awareness.

  • Selective Attention: The mechanism used to focus on specific details while discarding irrelevant sensory data.

  • Working Memory: Related to short-term memory, but allows for the active manipulation and processing of information.

  • Capacity: Approximately 77 to 99 individual information bits.

  • Duration: Information typically lasts 2020 to 3030 seconds unless extended through rehearsal.

  • Chunking: A method to increase retention by grouping individual bits into meaningful units (e.g., grouping the numbers 1,9,8,41, 9, 8, 4 into the year 19841984).

Long-Term Memory (LTM)

  • LTM is a seemingly limitless and relatively permanent storage system.

  • Information in LTM is stored according to meaning and organized into mental constructs called schema.

  • Procedural Memory: Long-term memory for actions and skills (e.g., riding a bike); it is implicit, conditioned, and associated with the hindbrain and cerebellum.

  • Declarative Memory: Long-term memory for explicit, factual information, divided into two types:

    • Semantic Memory: Impersonal, fact-based knowledge about the world (e.g., words, numbers, symbols).

    • Episodic Memory: Personal memory regarding specific life events and experiences (e.g., a first kiss or a birthday).