- Memory – processes that allow us to record and later retrieve experiences and information
Memory as Information Processing
- Encoding – getting information into the system by translating into a neural code that your brain processes
- Storage – retaining information over time
- Retrieval – the process of accessing information in long term memory
Three-Component Model
- Three major components of memory:
- Sensory memory – holds incoming sensory information just long enough for it to be recognized
- Composed of sensory registers:
- Iconic store (visual sensory)
- Echoic store (auditory sensory) – lasts longer than iconic
- Composed of sensory registers:
- Short-Term/Working memory – type of memory that holds the information that we are conscious of at any given time
- Working memory refers to fact that it consciously processes, codes, and works on information
- Mental representations are how information is coded to be retained in short term memory
- When reading words, information is stored as phonological codes
- Short term memory can only hold limited information
- Most people can hold no more than five to nine meaningful items
- Chunking – combining individual items into larger units of meaning
- Maintenance rehearsal – simple repetition of information
- Elaborative rehearsal – involves focusing on the meaning of information or relating it to other things we already know
- Three components of working memory (according to Alan Baddeley):
- Auditory working memory – repetition of information to self
- Visual spatial working memory – temporary storage and manipulation of images and spatial information
- Central executive – decides how much attention to allocate to mental imagery and auditory rehearsal
- Long-Term memory – vast library of more durable stored memories
- Serial position effect – recall of information is influenced by a word’s position in a series of items
- When given a long list of words, the beginning and ending words are most remembered
- Primacy effect – superior recall of early words
- At first, brain rehearses beginning words, storing into long term memory
- List gets longer, and short term memory fills up
- Recency effect – superior recall of recent words
- Last words remembered since they aren’t bumped out of short term memory by newer words
- Primacy effect – superior recall of early words
- When given a long list of words, the beginning and ending words are most remembered
- Serial position effect – recall of information is influenced by a word’s position in a series of items
- Sensory memory – holds incoming sensory information just long enough for it to be recognized
Encoding: Entering Information
- Effortful processing – encoding that is initiated intentionally and requires conscious attention
- Automatic processing – encoding that occurs without intention and requires minimal attention
Levels of Processing
- Structural encoding – processing based on structure of information
- Phonological encoding – processing based on sound
- Semantic encoding – processing based on meaning
- Levels of processing concept: the more deeply we process information, the better it is remembered
- Semantic encoding involves most processing, since meaning must be focused on
- Reason why elaborative rehearsal is more effective than maintenance rehearsal
Organization and Imagery
- Hierarchies and chunking
- Takes advantage of principle that memory is enhanced by associations between concepts
- Chunking widens information processing caused by limited capacity of short term memory (e.g. encoding phone number in sets of numbers)
- Mnemonic devices
- Mnemonic device is any type of memory aid (including hierarchies and chunking)
- Does not reduce amount of information to encode, but provides extra cues to retrieve information
- Visual imagery
- Dual coding theory – encoding information using both codes (verbal and nonverbal) enhances memory
- Odds improve that at least one of the codes will be available
- Dual coding theory – encoding information using both codes (verbal and nonverbal) enhances memory
- Schema – an organized pattern of thought about some aspect of the world
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- Create a perpetual set
Storage: Retaining Information
Memory as a Network
- Associative network – a massive network of associated ideas and concepts
- Priming – activation of one concept by another (e.g. “fire engine” primes the node for “red”)
- Neural network – each concept is represented by a particular pattern or set of nodes that becomes activated simultaneously
Types of Long-Term Memory
- Declarative and Procedural memory
- Declarative – involves factual knowledge, broken into two subcategories:
- Episodic memory – store of factual knowledge concerning personal experience
- Semantic memory – general factual knowledge about the world and language, including words and concepts
- Procedural – memory reflected in skills and actions
- One component consists of skills involved in “doing things” in particular situations
- Other component reflects classical conditioning effects
- Declarative – involves factual knowledge, broken into two subcategories:
- Explicit and Implicit memory
- Explicit – involves conscious or intentional memory retrieval
- Implicit – occurs when memory influences our behaviour without conscious awareness (e.g. riding a bike, driving)
Retrieval: Accessing Information
- Retrieval cue – any stimulus (internal or external) that stimulates the activation of information stored in long-term memory
- Multiple self-generated cues is most effective way to maximize recall
- Flashbulb memories – recollections that seem so vivid and clear, that they can be pictured as if they were a snapshot of a moment of time
- Accuracy of these memories fades over time
Context, State, and Mood Effects on Memory
- Encoding specificity principle – memory is enhanced when conditions present during retrieval match those that were present during encoding
- Context dependent memory – phenomenon that it is typically easier to remember something in the same environment in which it was acquired
- State dependent memory – ability to retrieve information is greater when our internal state at the time of retrieval matches the original state during learning
- Does not extend to mood states
- Mood congruent recall – tendency to recall information or events that are congruent with our current mood
- Does not extend to mood states
Forgetting
- Forgetting tends to occur more rapidly at first, then slows down
- Most of forgotten information occurs right away, then only a little forgotten over rest of time
Why Do We Forget
- Encoding failure – information was never encoded into long term memory
- Decay theory – proposes that with time and disuse, the physical memory trace in the nervous system fades
- Problem in prediction that longer intervals of disuse cause increased decay of information
- Reminiscence – phenomenon where more material is recalled during second testing of information than the first
- Problem in prediction that longer intervals of disuse cause increased decay of information
- Two types of interference:
- Proactive interference – occurs when material learned in the past interferes with recall of new material (e.g. learning a new phone number)
- Retroactive interference – occurs when newly acquired information interferes with the ability to recall earlier acquired information (e.g. recalling an old phone number)
- Tip of the tongue phenomenon does not always reflect a retrieval of information problem (sometimes the answer is never known to begin with)
- Motivated forgetting – motivational processes (e.g. repression) may protect us by blocking the recall of anxiety-arousing memories
Amnesia
- Retrograde amnesia – memory loss for events that occurred prior to the onset of amnesia
- Anterograde amnesia – memory loss for events that occur after the initial onset of amnesia
- Infantile amnesia – memory loss for events that occurred during the first few years of our lives
- Experienced by everyone
Forgetting to do Things
- Prospective memory – concerns remembering to perform an activity in the future
- People with better retrospective memory don’t have better prospective memory
The Misinformation Effect and Eyewitness Testimony
- Misinformation effect – distortion of a memory by misleading post-event information
- Source confusion – tendency to recall something or recognize it as familiar, but to forget where it was encountered
The Biology of Memories
Where in the Brain are Memories Formed?
- Hippocampus and Cerebral Cortex
- Hippocampus and adjacent tissue help encode and retrieve long term declarative memories
- Cortex encodes by processing information from sensory registers
- Memory consolidation – creation and binding together of neural codes that allow information to be transferred from short term memory into long term memory
- Consolidation in hippocampus allows for many components to become a unified memory
- Thalamus and Amygdala
- Damage to thalamus can produce amnesia
- Amygdala encodes emotionally arousing and disturbing aspects of events
- Damage can disrupt conditioned fear response
- Cerebellum
- Plays an important role in the formation of procedural memories
