memory

Memory Overview

3 Basic Forms of Memory

• Sensory Memory:

  • Brief representations of physical features of stimuli.

  • Stored for a very short time only.

• Short-term (Working) Memory:

  • Immediate memory for stimuli that have just been perceived.

• Long-term Memory:

  • Memory in which information is stored on a near-permanent basis.

3 Stages of Memory

• Encoding:

  • Process of converting stimulus information into a usable form for memory.

• Storage:

  • Maintaining information in memory for future use.

• Retrieval:

  • Locating and using information that is stored in memory.

The Capacity of Short-Term Memory (STM)

• STM is often described by the "magical number 7, plus or minus 2" based on the number of items it can hold.

• Research by Peterson and Peterson (1959):

  • Subjects presented with consonant trigrams (e.g., JRG) and engaged in backward counting to prevent rehearsal.

  • Found that STM holds information for 15-20 seconds without rehearsal.

Chunking

• Definition: Breaking down information into smaller, meaningful components.

• Example: Transforming a complex string (XIBMCIAFBICBSMTV) into manageable chunks.

• Notable example: Rajan Mahadevan excels at chunking to remember long strings.

Schemas

• Definition: Cognitive frameworks that represent knowledge and assumptions about specific aspects of the world.

Explicit vs. Implicit Memory (Storage)

• Explicit Memory:

  • Conscious and voluntary remembering of information.

• Implicit Memory:

  • Remembering that occurs without conscious awareness.

  • Example: Individuals with anterograde amnesia can recall past events but not new ones.

• Patient H.M.:

  • Suffered damage to the hippocampus affecting explicit memory—could not form new memories post-surgery.

  • Described his experience as waking from a dream with no memory of past events.

Types of Explicit Memory

• Episodic Memory:

  • Memory of personal events or episodes.

• Semantic Memory:

  • Knowledge about the world not tied to personal experiences.

Types of Implicit Memory

• Procedural Memory:

  • Knowledge about how to perform tasks and actions.

Encoding and Retrieval

• Retrieval Cues:

  • Stimuli associated with stored information that assist in retrieval.

• Scuba Diver Study:

  • Memorized information in different environments (on land vs. underwater). The study demonstrated that memory retrieval is context-dependent.

Reconstructive Memory

• Loftus and Palmer's Study (1975):

  • Investigated memory distortion through leading questions about a car accident.

  • Example questions: "How fast were the cars going when they contacted/bumped/hit/smashed into each other?"

Results of Recall Instructions

• Participants' speed estimates varied based on wording:

  • "Smashed": 42 mph

  • "Contacted": 32 mph

Loftus and False Memory Syndrome

• False Memories:

  • Memories of events that did not occur, but which a person firmly believes are true.

• Source Monitoring Errors:

  • Misidentifying the origin of specific memories.

• Reality Monitoring Errors:

  • Misidentifying whether memories are based on real experiences or imagined scenarios.

Experiment Details

• Methodology:

  • Contacted parents to verify real childhood events while ensuring one target event was false.

  • Conducted multiple interviews with subjects to gauge recollections of both true and false events.

• Findings: Comparison of recalled events demonstrated a notable percentage of subjects reporting false memories, reinforcing the fallibility of memory.