Levels of Processing Model Retention depends upon how deeply information is processed The shallowest levels of processing occur when the person is merely aware of the incoming sensory information. Deeper processing takes place only when the person does something with the information –Makes associations –Attaches meaning –Actively elaborates
Memory Retrieval Varies in Difficulty Recall Serial recall Free recall Retrieval cue Recognition – hippocampus Relearning - savings
Context Effects Improve Retrieval Many elements of the physical setting in which we learn information are simultaneously encoded into long-term memory. Those stimuli or similar stimuli will allow us to more easily recall information from long-term memory These stimuli appear to serve as retrieval cues.
Context Effects –memory works better in the context of original learning –Good reason for coming to class –Holidays
Context Effects Water/ land Land/ water Water/ water Different contexts for hearing and recall Same contexts for hearing and recall Land/ land Percentage of words recalled
Psychological Retrieval Cues Our internal psychological environment can also be encoded and become part of our memory strands. State-dependent memory: –The tendency for retrieval from memory being better when our state of mind during retrieval matches our state during encoding. –Mood-dependent memory
Encoding Specificity Principle –Encoding specificity principle: a retrieval rule stating that retrieving information from long-term memory is most likely when the conditions at retrieval closely match the conditions present during the original learning
Reconstruction of Memory Elizabeth Loftus –What a person usually recalls is not a replica, but a reconstruction of the event –A reconstruction is an account which is pieced together from a few highlights, using information which may or may not be accurate.
Memories Are Reconstructions of the Past The scientific belief in the reconstructive nature of memory was first proposed in the 1930s by Sir Frederic Bartlett. –By testing people’s memories of stories they had read, Bartlett found that accurate recollections were rare. –Errors increased over time.
Memories Are Often Sketchy Reconstructions of the Past Bartlett concluded that – The parts that participants were most confident of remembering were often those that they had created. People systematically distort details (facts and circumstances). People are largely unaware they have reconstructed the past, and Information already stored in memory strongly influences how new information will be remembered.
Memories are Affected by Schemas Schemas are integrated frameworks of knowledge and assumptions a person has about people, objects and events. They influence what people notice and how they encode and recall information. In other words, we distort new information to fit our existing schemas.
Memories Are Affected by the Introduction of Inaccurate Information Misinformation effects: distortions and alterations in people’s memories due to them receiving misleading information during questioning
Depiction of actual accident Leading question: “About how fast were the cars going when they smashed into each other?” Memory construction Misinformation Effect Eyewitnesses reconstruct memories when questioned
Source Confusions Can Create Memory Illusions Sometimes we forget the true source of an episodic memory and may experience a memory illusion. Memory illusions appear to be shaped by implicit remembering.
Source Confusions Can Create Memory Illusions –Common types of memory illusion include: Déjà vu: a memory illusion in which people feel a sense of familiarity in a situation that they know they have never encountered before Cryptomnesia: (hidden or forgotten memory) a memory illusion in which people believe that some work they have done is a novel creation, when, in fact, it is not original
Most Forgetting Occurs Soon after Learning Much of what a person learns is quickly forgotten. –Herman Ebbinghaus’s research (1800s) Most forgetting occurred within 9 hours after learning. Everything about it may not be forgotten. Implication: most forgetting is not complete. –One reason for forgetting (encoding failure): Not being sufficiently attentive when information is presented
Ebbinghaus’s Forgetting Curve
Theory of Forgetting: Encoding Failure Which penny is the real thing?
Theory of Forgetting: Encoding Failure Forgetting as encoding failure External events Sensory memory Short- term memory Long- term memory Attention Encoding failure leads to forgetting
Theories of Forgetting: Storage Decay Decay Theory –Unless memories are periodically rehearsed, the passage of time causes them to fade and eventually decay.
Forgetting as Storage Decay Time in days since learning list Percentage of list retained when relearning 60 Retention, drops then levels off
Theory of Forgetting: Retrieval Failure Forgetting can result from failure to retrieve information from long-term memory External events Attention Encoding Retrieval failure leads to forgetting Retrieval Sensory memory Short-term memory Long-term memory
Theory of Forgetting: Interference Inteference Theory –Retroactive interference: forgetting due to interference from newly learned information –Proactive interference: forgetting due to interference from previously learned information
Interference in Memory
Theory of Forgetting: Motivation Motivated forgetting: forgetting due to a desire to eliminate awareness of some unpleasant or disturbing memory
Two Types or Theories of Motivated Forgetting Suppression occurs when a person consciously tries to forget something. Repression occurs when a person unconsciously pushes unpleasant memories out of conscious awareness. These memories continue to unconsciously influence the person’s thoughts, feelings, and behavior.
Can people repress & later recover memories? Many memory researchers believe: –It is naive to assume that people can accurately recover memories that were previously unconsciously repressed –People can unknowingly manufacture false memories. –False memories can be implanted into the minds of both children and adults.
Can people repress & later recover memories? Many psychologists believe that memories “recovered” in therapy are actually false or pseudo memories. Many research participants who are instructed to imagine that a fictitious event happened later develop a false memory of the fictitious event. False childhood memories can be experimentally induced.
Can people repress & later recover memories? Garry & Loftus implanted a false memory of being lost in a shopping mall at age 5 in 25% of their research participants (aged 18-53) after verification of the experience by a relative. “Memories” from the first years of life are very suspect. Psychologists believe that the brain in insufficiently developed to create or sustain a long-term (until older childhood or adulthood) memory in a child under age three.
Repressed & Recovered Memories? Simply repeating imaginary events to people causes them to become more confident that they actually experienced these events. Certain techniques used in therapy to recover childhood memories of abuse (hypnosis and dream interpretation) can distort patients’ recollections of past events and create false memories of abuse.
Repressed Memories Controversy Current evidence supports the possibility of repressed memories and also the construction of false memories in response to suggestions of others. American Psychological Association, American Psychiatric Association, American Medical Association
The Brain Physiology of Memory
Long-Term Potentiation May Be the Neural Basis for Memory There is no scientific consensus on what an engram (or memory trace) is or where it is located in the brain. However, it appears that memories begin as electrical impulses traveling between neurons, and that the establishment of long-term memories involves changes in these neurons.
How Does Storage Work? The Search for Memory Karl Lashley (1950) –trained rats to solve maze, then cut out pieces of their cortex and retested their memory of maze –partial memory retained –concluded memory is distributed
Parallel (simultaneous) Processing –Parallel processing of information is possible because millions of neurons are active at once, and each neuron is communicating with thousands of other neurons. –Parallel distributed processing models: models of memory in which a large network of interconnected neurons, or processing units, distributed throughout the brain simultaneously work on different memory tasks
Parallel Processing Parallel distributed processing models: –Contend that information in memory is not located in a specific place in the brain, but instead, resides in connections between the involved processing units in the neural network. –Better represents the actual operation of the brain.
How Does Storage Work? The Search for Memory Long-Term Potentiation –A long-lasting increase in the efficiency of neural transmission at the synapses (junctions or connection points between nerve cells). –Donald O. Hebb argued that learning and memory must involve the enhancement of transmission at the synapses
How Does Storage Work? The Search for Memory Long-Term Potentiation –increase in synapse’s firing potential after brief, rapid stimulation –Kandel & Schwartz (1982) – classically conditioned aplysia –Neural connections released more neurotransmitter, became more sensitive/efficient –Increased number of receptor sites
Long-term Potentiation Double receptor sites Event 1Event 2 Classical Conditioning: Sea snail associates splash with a tail shock
Long-Term Potentiation May Be the Neural Basis for Memory Long-term potentiation: the long-lasting strengthening of synaptic transmission along a specific neural circuit, which is believed to be the neural basis for long-term memory –When a new memory is formed, changes occur in specific neurons, creating a kind of memory circuit. –Each time the new memory is recalled, the neurons in this new circuit are activated, which strengthens their neural connections. –As the communication links between the neurons increase in strength, the memory becomes established as a long-term memory.
Biological Factors Affecting Memory Processing Strong emotions make for stronger memories – stress hormones boost learning & retention; anxiety affects memory (cortisol) Drugs like alcohol that block neurotransmitters may prevent memory storage (retrograde amnesia) Blows to the head and electric current may also block information storage.
Brain Regions Involved in Memory Formation & Storage –The hippocampus appears to be most important in the encoding of new explicit memories and the transfer of them from short- term to long-term memory.
Brain Regions Involved in Memory Formation & Storage –Implicit memory: The neocortex, striatum, and amygdala play important roles in the type of long-term memory previously identified as implicit memory. –Explicit memory: Several brain regions are involved, including the hippocampus and nearby portions of the cortex and the thalamus.
Brain Regions Involved in Memory Formation & Storage The inability to form new memories due to the brain experiencing physical injury is called anterograde amnesia. This appears to be caused by damage to the hippocampus. Explicit memories cannot be formed, but implicit memories can.