Lecture 4 - Memory 1: What is memory? Flashcards
Experiences are stored as
patterns of activity in networks of neurons
Experience and how it is recorded summary
When you are having an experience you have a network of neurons that are active (generating action potentials and graded potentials) communicating with each other and it is a unique pattern for a experience but to hold that experience into memory you do not want these neurons to have to fire on and off constantly for weeks and months so you save this information by strengthening the connections/synapses so at layer times with appropriate cues you are likely to recall the event therefore when you are remembering something you are reactivating many of the neurons that were originally activated whilst you had that experience
An increase in synaptic strength could be mediated by:
An increase in neurotransmitter release
An increase in postsynaptic response (increase the number of receptors available to receive the chemical signal generated by the neurotransmitter)
An increase in synaptic connections between neurons
All three of these mechanisms occur when a memory is stored but will occur at a different time
William Greenough study
Raise rats separately in impoverished, social and enriched conditions. Learning produces change in synaptic connectivity
Results = The enriched environment produces much more complexity in the network of neurons, there are far more cells connected to each other and many more connections between neurons
What is memory?
Memory is the recording of the past for later use in the present
Genetic memory
Inherited behaviour
Levels of explanation of memory
Biological, individual, social and cultural levels of explanation of memory
Biological level of memory
Focus - brain systems, neurochemistry, genetics
What is studied?
Neuroanatomy, animal research, brain imaging
Neurotransmitters and hormones, animal studies, drug studies
Gene mechanisms, heritability, twin and adoption studies
Individual level of memory
Focus - Individual differences, Perception and cognition, Behaviour
What is studied?
Personality, gender, developmental age groups, self-concept
Thinking, decision making, language, memory, seeing, hearing
Observable actions, responses, physical movements
Social level of memory
Focus - Interpersonal behaviour, social cognition
What is studied?
Groups, relationships, persuasion, influence, workplace
Attitudes, stereotypes, perceptions
Cultural level of memory
Focus - Thoughts, actions, behaviours- in different societies and cultural groups
What is studied?
Norms, beliefs, values, symbols, ethnicity
Memory at the individual involves three processes…
Encoding
Storage
Retrieval
Encoding
The conversion of information into a FORM that can be stored in memory
Information from the world into action potentials/potentials
Storage
The creation of a TRACE of this information within the nervous system
Retrieval
An attempt to RECOVER a memory trace
Note - Could be accurate and successful retrieval, sometimes it is not successful and sometimes there is an error where you think you have a memory but there actually is not one
Unitary model of memory
Input then encoding then storage then retrieval and from retrieval you get output or forgetting
retention for decades, massive capacity
Forgetting
Forgetting = lost completely from the memory store or retrieval is not successful and the information is actually still there
Hermann Ebbinghaus
(1850-1909)
was the first person to investigate memory scientifically and systematically
Ebbinghaus’ forgetting curve
Memorised nonsense syllables then tested how many he retained over time.
Criticisms: not normal memory function, unusual content may enhance memory. Non linear scale. Down to ~60% after 20 mins, ~20% after 31 days
The advantage of doing this is that you are starting from scratch. If you give them a word they know, chances are that at some point they will see the word in the real world and it will prepare them e.g. car (there is potential throughout the retention period to rehearse the information as you are receiving cues from the world around you)
The disadvantages are that these words are not relevant to us as it is not meaningful information and usually the more meaningful the information is the better you remember it therefore you lose the motivation. This is not the way that memory generally works
Peterson and Peterson’s (1959) experiment
3 letters and 3 numbers presented.
Subject counts backwards in 3s from the number they saw for 18 sec, then recalls letters. When working memory takes on a new task, old information disappears very quickly (~18 sec)
Miller study
Short-term memory capacity = 7 +/- 2 items
Given numbers and then asked to write them down
Which studies question the unitary model of memory
Peterson and Peterson
Miller
Ebbinghaus’ forgetting curve
Memory refers to
the processes that allow us to record, store and later retrieve experiences and information
Encoding refers to
getting information into the system by translating it into a neural code that your brain processes
Storage involves
retaining information over time
Retrieval refers to
processes that access stored information
Sensory memory ..
briefly holds incoming sensory information
Atkinson and Shiffrin (1968) depicts memory as having three major components …
sensory memory
working (short term) memory
Long term memory
Short term memory is a
memory store that temporarily holds a limited amount of information
Memory codes are
mental representations of some type of information or stimulus and they can take various forms
Short term memory can hold
only a limited amount of information at a time
The limit of short term memory storage capacity concerns the
number of meaningful units that can be recalled
combining individual items into larger units of meaning is called chunking
By rehearsing information….
you can extend its duration in short term memory
