Understanding Memory: Encoding and Storage

• Memory is the cognitive process of encoding, storing, retaining and retrieving information
• It is essential for learning and adapting to the environment

Memory Encoding

• Encoding is the initial processing of information so that it can be stored
• It is the first step in creating a memory
• Encoding involves converting sensory input into a form that the brain can understand and use
  • This can be visual, acoustic, or semantic
• Different encoding strategies can affect how well information is remembered
  • Elaborative encoding, which involves making connections between new information and existing knowledge, tends to lead to better memory than rote memorization

Memory Storage

• Storage is the retention of encoded information over time
• It involves maintaining information in the brain for later use
• There are several types of memory storage:
  • Sensory memory: Briefly holds sensory information
    • It has a very large capacity but a very short duration (less than a few seconds)
  • Short-term memory: Briefly holds information that is currently being used or attended to
    • It has a limited capacity (about 7 items) and a short duration (about 20 seconds)
  • Long-term memory: Stores information for a long time
    • It has a virtually unlimited capacity and can store information indefinitely
• Memory consolidation is the process by which short-term memories are transferred into long-term memories
  • This process is thought to involve the hippocampus and other brain structures

Memory Retrieval

• Retrieval is the process of accessing stored information
• It is the final step in memory
• Retrieval can be affected by a variety of factors, such as:
  • The way the information was encoded
  • The context in which the information is being retrieved
  • The presence of retrieval cues
• There are two main types of retrieval:
  • Recall: Retrieving information without any cues
    • Example: answering an open-ended question on a test
  • Recognition: Identifying information that has been previously learned when it is presented again
    • Example: answering a multiple-choice question on a test

Types of Memory

• Sensory memory:
  • Initial stage of memory
  • Briefly holds sensory information
  • Includes iconic memory (visual) and echoic memory (auditory)
  • Large capacity, but very short duration (milliseconds to seconds)
• Short-term memory (STM):
  • Also known as working memory
  • Limited capacity (7 +/- 2 items)
  • Brief storage (seconds to minutes)
  • Involved in conscious processing and manipulation of information
• Long-term memory (LTM):
  • Relatively permanent and limitless storage of information
  • Includes explicit (declarative) and implicit (non-declarative) memory
• Explicit memory (declarative):
  • Conscious recall of facts and events
  • Includes semantic memory (general knowledge) and episodic memory (personal experiences)
• Implicit memory (non-declarative):
  • Unconscious recall of skills and habits
  • Includes procedural memory (motor skills), priming (enhanced identification of objects or words), and classical conditioning (learned associations)

Forgetting

• Forgetting is the inability to retrieve information that has been stored in memory
• There are several reasons why forgetting can occur:
  • Encoding failure: Information was never properly encoded in the first place
  • Storage decay: Memories fade over time if they are not used
  • Retrieval failure: Information is stored in memory, but cannot be accessed
  • Interference: Other information interferes with the retrieval of the target information
    • Proactive interference occurs when old information interferes with the retrieval of new information
    • Retroactive interference occurs when new information interferes with the retrieval of old information
  • Motivated forgetting: People may intentionally try to forget unpleasant or traumatic memories
• The forgetting curve, discovered by Hermann Ebbinghaus, shows that memory loss is most rapid shortly after learning, and then levels off over time

Factors Affecting Memory

• Attention: Attention is necessary for encoding information into memory
  • Divided attention can impair memory performance
• Emotion: Emotional events tend to be better remembered than neutral events
  • This is because emotional events trigger the release of hormones that enhance memory consolidation
• Stress: Chronic stress can impair memory function, especially in the hippocampus
• Sleep: Sleep is important for memory consolidation
  • Sleep deprivation can impair memory performance
• Age: Memory function declines with age
  • This is due to a variety of factors, such as changes in brain structure and function

Memory Improvement Techniques

• Mnemonics: Memory aids that use imagery, organization, or other techniques to improve encoding and retrieval
  • Examples include acronyms, acrostics, and the method of loci
• Spacing effect: Distributed practice (studying over a longer period of time) is more effective than massed practice (cramming)
• Testing effect: Testing yourself on material is more effective than simply rereading it
• Elaborative rehearsal: Making connections between new information and existing knowledge
• Organization: Organizing information into meaningful categories or hierarchies
• Paying attention: Focusing on the information that you want to remember
• Getting enough sleep: Sleep is important for memory consolidation
• Reducing stress: Chronic stress can impair memory function

Memory Disorders

• Amnesia: Loss of memory due to brain damage or trauma
  • Anterograde amnesia is the inability to form new memories
  • Retrograde amnesia is the loss of memories from the past
• Alzheimer's disease: A progressive neurodegenerative disease that causes memory loss and cognitive decline
  • It is the most common cause of dementia
• Korsakoff's syndrome: A chronic memory disorder caused by thiamine deficiency
  • It is often associated with chronic alcoholism
• Traumatic brain injury (TBI): Brain damage caused by a blow or jolt to the head
  • TBI can cause a variety of memory problems, depending on the severity and location of the injury