Long Term Memory:
Remembering and Forgetting
Overview
• Explicit and Implicit Memory
• Forgetting
– Decay, Interference, Retrieval Induced and
Directed Forgetting
• Memory Distortion and False Memories
• Eyewitness Memory
Types of Memory
• Explicit (Declarative)
– Semantic
– Episodic (including Autobiographical)
• Implicit (Nondeclarative)
– Procedural
– Priming
– Conditioning
• Habituation and Sensitization
Explicit vs. Implicit Memory:
Amnesia Cases
• MT (Schacter, 1983)
• HM – loss of temporal lobes due to
epilepsy
• Clive Wearing
Explicit vs. Implicit Memory:
Prejudice
• Prejudice seems to have declined in the
last 50 years
• People are less likely to indicate they
hold prejudices when asked in surveys
• Implicit Association Test
Decay Theory
• Began with Ebbinghaus (1885)
• Over time, unused memories weaken
and fade away
• Controversial
– Implies only passage of time
– Perhaps correct cues have not been
rediscovered
Interference Theory
• Memories interfere with each other
– Proactive and Retroactive Interference
• Reasons for Interference
– Response competition
– Unlearning
Retrieval Induced Forgetting
• Remembering some aspects of an
event can impair retrieval for other
aspects of an event
• Anderson, Bjork, and Bjork (1994)
• Shaw, Bjork, and Handal (1995)
Directed Forgetting
• Voluntary and purposeful forgetting of
information
• Sahakyan & Delaney, 2003- lists and
the cost/benefit analysis
• Joslyn and Oakes, 2004- diary study
Memory Distortion: Bias
• Hastorf and Cantril (1954): They Saw a
Game
False Memories
• Lost in a Mall (Pickrell and Loftus, 1995)
• Imagination Inflation– Garry, Manning, Loftus, and Sherman
(1996)
– Thomas and Loftus (2002)
False Memories
• Source misattribution
• Advertising
The Impact of Eyewitnesses
• Center for Wrongful Conviction study of
86 legally exonerated people found:
– 53.5%: Eyewitness testimony played a role
– 38.4%: Eyewitness was only evidence
– In 32 cases, only 1 eyewitness
• Mock Jury study
• Eyewitness confidence is related to
juror conviction
Event Factors
• Exposure time
• Detail Salience
• Types of Facts
– Duration, Speed, Distance
Witness Factors
• Stress and memory
– Weapon focus
• Expectations
– Biases
– Cultural beliefs
The Misinformation Effect
• Loftus, Miller and Burns (1978)
• Leading/Suggestive questioning
• Social contagion effects
• Lineups and Mugshots