Memory is a complex cognitive process that shapes our experiences and knowledge. It involves encoding, storing, and retrieving information through various stages and types. Understanding how memory works can help us improve our learning and recall abilities.

Long-term memory is divided into procedural and declarative types. Procedural memory handles skills and habits, while declarative memory stores facts and events. These systems work together to form our comprehensive knowledge base and influence our daily lives and decision-making.

Memory Functions and Stages

Core functions of memory

• Encoding converts sensory information into a form that can be stored in memory involves attention and perception
  • Visual encoding converts visual sensory information (images, scenes) into memory
  • Acoustic encoding converts auditory sensory information (sounds, words) into memory
  • Semantic encoding converts the meaning of sensory information (concepts, ideas) into memory
• Storage retains encoded information in memory over time involves different stages (sensory, short-term, and long-term) requires consolidation which stabilizes memory traces
  • Memory consolidation is the process of stabilizing a memory trace after initial acquisition
• Retrieval accesses stored information from memory involves recall and recognition
  • Recall retrieves information from memory without cues (remembering a phone number)
  • Recognition identifies previously encountered information with cues (recognizing a face)

Stages of memory storage

• Sensory memory briefly stores sensory information for less than a second has a large capacity
  • Iconic memory is visual sensory memory (afterimage of a bright light)
  • Echoic memory is auditory sensory memory (echo of a loud noise)
• Short-term memory (STM) has a limited capacity of 7 ± 2 items lasts 15-30 seconds without rehearsal maintained by rehearsal
  • Working memory actively manipulates information in STM (mental math)
• Long-term memory (LTM) has a virtually unlimited capacity and potentially permanent duration requires encoding and consolidation retrieval can be affected by interference and forgetting
  • The forgetting curve illustrates how information is lost over time when there is no attempt to actively retrieve it

Types of Long-Term Memory

Procedural vs declarative memory

• Procedural memory stores skills and habits is implicit and unconscious acquired through practice and repetition
  • Examples include riding a bike, typing, playing an instrument
• Declarative memory stores facts and events is explicit and conscious can be verbally declared has two subtypes
  • Semantic memory stores general knowledge and facts not tied to specific personal experiences
    • Examples include capital cities (Washington D.C.), historical dates (July 4, 1776), vocabulary
  • Episodic memory stores personal experiences and events tied to a specific time and place includes autobiographical details
    • Examples include your first day of school, your last birthday party, a memorable vacation

Memory Disorders and Phenomena

• Amnesia is a condition characterized by significant memory loss
  • Retrograde amnesia involves the loss of memories formed before a specific event or time
  • Anterograde amnesia involves the inability to form new memories after a specific event or time
• Memory reconsolidation occurs when previously consolidated memories become labile upon retrieval and require restabilization
• False memories are recollections that feel real but are fabricated or distorted