Memory Models • Memory—An internal record or representation of some prior event or experience. • Three-stage model—humans need to store information for different lengths of time—sensory memory, short-term memory, long-term memory • Encoding, storage and retrieval—(computer model) memory is a process of encoding, storage and retrieval • Biological Approach—memory is explained by looking at biological changes in synapses
Three-Stage Memory Model • Sensory Memory—First memory stage that holds sensory information; relatively large capacity, but duration is only a few seconds • Retains a relatively exact image of sensory experience • (think of your “shopping cart”)
Three-Stage Memory Model • Short-term memory—Second memory stage that temporarily stores sensory information and decides whether to send it on to long-term memory; capacity limited to 5-9 items and duration is about 30 seconds (think “cupboard or closet”) • Maintenance rehearsal—repeating information over and over to maintain it in STM • Chunking—grouping pieces of information to form a single unit (or chunk)
Short-term memory • Visuospatial sketchpad—holds and manipulates visual images and spatial information • Phonological rehearsal loop—holds and manipulates verbal information • Central executive—supervises and coordinates the other two components as well as retrieval from LTM.
Long-Term Memory • Third stage of memory that stores information for long periods of time’ its capacity is virtually limitless and its duration is relatively permanent • (think “those boxes of important purchases that are in your attic”)
Encoding, Storage and Retrieval Model • Memory is like a computer (or computers are modeled after our memory) • Information is Encoded, that is it is translated into neural codes • Neurally coded information is retained over time (storage) • Information stored in memory can be recovered (retrieval)
A problem and solution • Unlike computers which store and retrieve information sequentially or linearly, the brain stores and retrieves information simultaneously through multiple networks • Parallel Distributed Processing (PDP)—Memory results from connections among interacting processing units, distributed in a vast network and all operating parallel
Integrating the two models Encoding Retrieval
Integrating Encoding • Organization—information is organized to aid in its encoding. STM may use chunking whereas LTM may use hierarchies (arranging items into broad categories that are further divided and subdivided) • Rehearsal—in STM, maintenance rehearsal is used. In LTM, elaborative rehearsal • Linking new information to previously stored material
Elaborative rehearsal techniques • Create a personal example • Expand or elaborate on the information • Actively explore and question new information • Try to find meaningfulness
Integrating Storage • Explicit/Declarative Memory—Subsystem within long-term memory that consciously stores facts, information and personal life experiences. • Semantic Memory—a part of explicit/ declarative memory that stores general knowledge; a mental encyclopedia or dictionary • Episodic Memory—a part of explicit/ declarative memory that stores memories of personally experienced events; a mental diary of a person’s life.
Integrating Storage • Implicit/nondeclarative Memory—Subsystem within LTM that consists of unconscious procedural skills, simple classically conditioned responses and priming • Priming—prior exposure to a stimulus (or prime) facilitates or inhibits the processing of new information, even when one has no conscious memory of the initial learning or storage
Integrating Retrieval • Retrieval Cue—a clue or prompt that helps stimulate recall and retrieval of a stored piece of information from LTM • Recognition—retrieving a memory using a specific cue (i.e., multiple choice and matching exam questions) • Recall—retrieving a memory using a general cue (i.e., f-i-b, short answer and essay exam questions)
Encoding Specificity Principle • Retrieval of information is improved when conditions of recovery are similar to the conditions when the information was encoded • Context and retrieval • Mood congruence • State-dependent retrieval
Biological Perspective • Neuronal and Synaptic Changes • Long-Term Potentiation (LTP)—long-lasting increase in excitability believed to be a biological mechanism for learning and memory • Hebb’s Law—If neuron i is near enough to excite neuron j and repeatedly participates in its activation, the synaptic connection between these two neurons is strengthened and neuron j becomes more sensitive to stimuli from neuron i.
Hebb’s Law in Plain Language • Neurons that fire together get wired together. • On a neurological level, memory is demonstrated through the sensitivity of one neuron to another and the formation of neural pathways in the brain.
Biological Perspective • Hormonal Changes • Hormones such as epinephrine and cortisol increase the encoding and storage of memories • Flashbulb memories—vivid images of circumstances associated with surprising or strongly emotional events.
Memory Failures • Serial position effect—remembering information at the beginning and the end of a list better than material in the middle. • Spacing of practice • Distributed practice—practice (or study) sessions are interspersed with rest periods • Massed practice—time spent learning is grouped (or massed) into long, unbroken intervals (a.k.a., cramming)
Theories of Forgetting • Decay theory—(Hebb’s law in reverse) like all biological processes, memory degrades over time. • Interference theory—one memory competes with or tries to replace another memory • Retroactive—new information interferes with remembering old information • Proactive—old information interferes with remembering new information.
Theories of Forgetting • Motivated Forgetting Theory—we may have reasons to try to forget, such as unpleasant or anxiety-producing memories • Suppression—consciously trying to forget • Repression—unconsciously forgetting anxiety-producing memories • Encoding Failure—during encoding, we decided that the information was not worth remembering, so, it did not get encoded
Theories of Forgetting • Retrieval Failure Theory—(cue-dependent theory) memories are not forgotten but are momentarily inaccessible due to interference, faulty cues, emotional states, etc. • Tip-of-the-Tongue Phenomenon—a retrieval failure that involves a sensation of knowing that specific information is stored in long-term memory but of being temporarily unable to retrieve it.
Organic Causes for Memory Problems • Brain Injury • Retrograde Amnesia—Loss of memory for events before an injury; backward-acting amnesia • Anterograde Amnesia—Inability to form new memories after and injury; forward-acting amnesia
Organic Causes for Memory Problems • Alzheimer’s Disease—Progressive mental deterioration characterized by sever memory loss
External Causes for Memory Problems • Since memory is a Constructive Process problems may be created within the processes of encoding and retrieval • Constructive Process—Organizing and shaping of information during encoding and retrieval that may cause memory errors and distortions
External Causes for Memory Problems • Source Amnesia—attributing to a wrong source an event that we have experienced, heard about, read about or imagined. • Sleeper Effect—Tendency to initially discount information from an unreliable source, but later consider it more trustworthy because the source is forgotten
External Causes for Memory Problems • Eyewitness testimony • Repressed/Recovered Memory Debate
Improving Memory—Helpful Tips • Pay attention and reduce interference • Use rehearsal techniques (maintenance and elaborative) • Improve your organization (chunking, hierarchies) • Counteract the serial position effect • Manage your time (distributed vs. massed practice) • Use the encoding specificity principle • Employ self-monitoring and overlearning
Mnemonic Devices • Mnemonic (from the Greek for “memory”)—memory-improvement technique based on encoding items in a special way • Method of loci—imagining the different pieces of information as rooms within a house • Peg-word—rhyming words with position on a list (one in a bun, etc.) • Substitute word—i.e., occipital—ox sip it all • Word associations—i.e., Roy G. Biv, etc.
Seven Sins of Memory • Sins of forgetting • Transcience—information not used is lost • Absentmindedness—lack of attention during encoding • Blocking—retrieval process is unable to happen • Sins of Distortion • Misattribution—incorrectly identifying the time, place, or person related to memory • Suggestibility—incorporating information suggested by someone else into our memory • Bias—current knowledge or needs distort memory of past • Sin of Persistence—traumatic or emotional events may cause memories to persist even when we would like to forget