Topic 6b: Memory

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Encoding: formatting of information from the external environment into a format usable and retrievable by the brain

stimuli perceived by the senses

signals travel to the thalamus and are synthesized into an experience

hippocampus analyzes the experience and determines if it should be encoded

4 main pathways used by humans to encode information:

visual encoding: The encoding of images and visual sensory information

the creation of mental pictures

this information is temporarily stored in iconic memory and then is moved to long- term memory for storage

amygdala has a large role

acoustical encoding: processing of verbal language and auditory information

phonological loop: auditory or verbal information is repeated in a person's echoic memory for improved storage and retrieval; Self vocalizations can also enhance auditory encoding (such as repeating a phone number out loud)

Elaborative encoding: the relation of new information to information that is already known for storage purposes

the recollection of the new memory becomes dependent on both the previous information and new information

studies show long- term retention of information is much improved when this form of encoding is used

semantic encoding: the storage of sensory information that has a certain meaning or context associated with it

chunking: combining information in a series of parts, to more easily store it in short- term memory

mnemonics: acronyms and physical cues (calendar on the knuckles of the hand) are used to recall information

Ways to improve encoding:

chunking

mnemonics

State- dependent memory: the use of environmental cues to improve recall of information

Retrieval cues play a large role in this technique; Example: listening to a certain song while learning a concept, and then playing that song to recall the learned concept.

Memory consolidation: processes that stabilize a memory trace after this first acquired; These influence whether the memory of an event is accessible later, similar to encoding

the processes involved in consolidation are more unconscious and happen at the cellular or neurological level, and do not require focus the way that encoding does.

sleep has a large role in consolidation, and one memory- enhancement technique is to play an audio recording of information you want to remember while trying to fall asleep.

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Memory storage: accomplished via encoding and consolidation

memories are not stored as exact replicas of experiences; Rather they are modified and reconstructed during retrieval and recall

long- term memory can hold much more information than short- term memory, however information in long- term memory is not immediately accessible, because when the memories are consolidated, they are done so in a way that optimizes space for other memories.

Sensory memory: the retention of impressions of sensory information for a short amount of time after the original stimulus is gone

this is an automatic response considered outside of cognitive control

allows one to remember great sensory detail about complex stimuli after it is presented

very short retention time of up to 5 seconds

echoic memory: memory of auditory stimuli

iconic memory: memory of visual stimuli

Working memory: AKA a short- term memory

the ability to hold information for some seconds

information is quickly lost if not stored in short- term memory when it is first received

several elements can be held in short- term memory simultaneously, however they compete for recall or degrade each other

long- term memory: the ability to hold information for an extended period of time

explicit: AKA declarative memory, those memories we can consciously remember

include episodic memories of experiences and semantic memories of common concepts

episodic memory: personal facts, time related information connected to your individual recollections (your first birthday party)

implicit memory: less conscious, “muscle memory”

include procedural memories, like knowing how to ride a bike and emotional conditioning

procedural memory: the ability to recall psychomotor skills

Items move from working to long- term memory via rehearsal, processing, and use.

Although the capacity of long- term memory is much greater than short- term memory, those memories are not permanent, and have to be recalled from time to time otherwise they will be forgotten.

Long- term memory storage can be affected by traumatic brain injury ---> amnesia: memory deficit caused by brain damage

anterograde amnesia: the inability to store new memories

retrograde amnesia: the inability to retrieve old memories prior to a specific point in time

Because there are different types of amnesia, the idea that memory has storage process is supported

Memory models to explain types of recall: These models must identify how an encoded memory can remain in storage until it is accessed in order to explain the recall process

multi- trace distributed memory model:

States that memories being encoded are converted to multiple memory traces, which are then added into a memory matrix

to retrieve the memory, a person must pull up the memory matrix with a particular related hint or aspect

limitations of this theory:

the idea that the memory matrix continuously grows with the addition of new traces and the idea of how memories could be found within the vast matrix both sound beyond the scope of human recall

Neural network model: states that form a highly interconnected complex network with other neurons

each neuron is characterized by the activation value (the amount of energy it takes to activate that neuron)

each neuronal connection is characterized by weight value (essentially ranking the strength of the connection between the two neurons)

connections are formed during the process of memory storage, strengthened by use, and weakened by disuse

this model maintains the useful features of the multi- trace model, while also addressing its limitations

search- of- associative- memory (SAM) model:

States that items in working memory will be recalled first during the recall process, and then items in the long- term storage

the probability of an item being recalled from long- term storage is proportional to the strength of the association within the long- term storage

the semantic matrix is used to explain the semantic effect associated with memory recall

semantic networks: the memory connections made by an individual's lifetime of memories and event

semantic memory: factual information that's not connected to individual recollection (happy birthday song)

spreading activation: the recall of one meaningful piece of information triggers the recalls of other pieces of information

Retrieval cues used to help recall or relearn information, they activate other neurons associated with that information, involves spreading activation via semantic networks

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retrieval: moving stored information back into conscious memory from long-term memory

context cues: where the information was learned, or activation of the semantic network of that information

Encoding specificity principle: explains why retrieval cues work

States people encode information in a specific way, which means the stronger the link between the cue and the memory, the better the recollection

3 types of retrieval --->

recognition: low cognitive load, an outside stimulus reminds a person they have learned this information in the past or a cue brings forth related information to the mind,

example: the process used while answering multiple- choice test questions, with the answer choices being the cue

recall: higher cognitive load, the ability to access the information directly from the memory, retrieval cues can also be helpful here

example: the process used while answering fill- in- the- blank test questions.

serial recall: remembering events or items in the order they occurred

serial-position effect: remembering the 1st and last items of a series and struggling to recall the middle items

free recall: having to recall multiple items but in any desired order

primacy effect: items that were presented 1st are better recalled as they are encoded into long-term memory

recency effect: items presented last are better recalled as they are still in working memory

cued recall: list of items to recall, and then when asked to recall, provided with cues

relearning: when information is relearned, there is a faster gain of information than when it was learned initially, as this only requires reactivation of dormant connections in the brain

retrieval can be affected by the amount of time since the information was retrieved, other information learned in the meantime, etc. --->

Spacing effect: repetitions of information over a long period of time results in stronger memories than repeating information in a smaller period of time

testing effect: practicing retrieval of a concept helps increase chances of remembering it

Role of emotion:

If a piece of information is learned while feeling a certain emotion, feeling that emotion again later can trigger the rise of that memory and other memories made while feeling that emotion

High emotional arousal can result in heightened attention to detail of an event, which may help in better encoding the memory

Emotion- congruent information: Aka “flashbulb memory," when powerful emotions create a vivid recollection that is like a snapshot of the moment. These memories degrade at the same rate as other memories, however we believe that these memories are accurate although they are not always. Practically, this present as difficulties with eyewitness testimony that occurs years after the event.

Emotion-discongruent information: it can be more difficult to recall information when you are feeling one emotion but you learned the information while feeling another

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Forgetting: dysfunctions of memory which can be natural or related to injury or disease

Memories are easier to recall the more recent they are

the more often information is repeated or used, the more likely it is entered into long-term memory

transience: deterioration of a memory over time, prevalent in short-term memory

working and episodic memory do show age-related declines, while crystallized and procedural memories do not appear to be significantly affected

major disease processes associated with memory loss:

dementia

picks disease and Alzheimer's disease: involved the formation of beta- amyloid plaques, which interfere with synapse transmission

korsakoff syndrome: prolonged alcohol use results in amin B1 deficiency, which causes chronic memory loss due to difficulty encoding new information and recalling previously learned information

Theories on why we forget:

decay theory: states that forgetting happens because of degradation of memory synapse overtime because of disuse. Postulates --->

all memories fade over time

a trace must be followed to recall a memory

if the trace is not used, it is degraded leading to recall difficulty or inability

rehearsal slows this process

memory decay causes retrieval failure

retrieval failure is also possible if:

the encoding specificity principle is not met, where the retrieval cue does not match well to the encoded memory.

this process is immediate (hence why we can forget names soon after we learn them)

interference: impacts memory because it prevents encoding or retrieval of information

retroactive interference: new information interferes with already learned information

proactive interference: old information prevents learning of new information

Other factors that affect memory retention:

absentmindedness: ineffective coding occurs secondary to low attention levels during learning, due to which we undergo events like misplacing keys, forgetting appointments, etc.

blocking: results in the “tip of the tongue” phenomenon; the brain tries to encode or recall information but another memory interferes with this. A part of the word or memory can usually be recalled, but recall is partial. A cue can help to gain full recall

false memory: remembering events differently from how they happened, or remembering events that did not happen; can be vivid, held with high confidence

Learning curve: established by Herman Ebbinghaus to show how quickly information degrades in the human memory

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learning: stimuli in the environment result in changes in the nervous system

Synaptic connections are the basis for memory and learning; These connections are selectively strengthened during encoding

the brain does continue to grow neurons, change synaptic connections, and form new connections throughout an individual's lifetime

3 main pathways:

long-term potentiation: the formation or strengthening of neural pathways via alteration of the flow of information within the brain using chemicals and electric impulses

a neuron shows increased excitability over time because of a repeated pattern, behavior, or response

long-term depression is the opposite of this, where there is decrease in synaptic strength

2. Habituation: the “behavior” version of sensory adaption; we learn to not respond to a repeated stimulus that has not changed

Fewer neurotransmitters are released at the synapse

3. Sensitization: strengthening of a neurological response to a stimulus because of the response to a secondary stimulus

more pre-synaptic neurotransmitters, resulting in a more excitable neuron

an exaggerated “startle” response, often seen in trauma patients

neural plasticity: changes to already present synaptic connections, as part of the brain's ability to adapt to new situations over time via potentiation

neural nets: collections of neurons that are activated in response to specific associations