MEMORY ‘’ When I was younger, I could remember anything, whether it had happened or not’’ Mark Twain
Definition of Memory
The mental processes used to encode , store and retrieve information
This takes many forms: visual, semantic, auditory, taste and smell. The information is transformed into codes, which create a memory trace, which is then stored in memory
Refers to the amount of
information that can be
stored in memory
How long information is
stored in memory
The process where information is dug out of memory, including recognition, recall and reconstruction.
The Multi-store Model of Memory In 1968 Atkinson & Shiffrin propose the classic three stage memory model
The case of H.M. (Blakemore 1988)
H.M. underwent an operation for epilepsy and his hippocampus was removed on both sides of the brain
He had severe amnesia, in that he had difficulty laying down memories, even though he could remember things before the operation
This evidence supports the claim that there is a short-term and a long-term memory
two different memory stores
Information is maintained by continued attention and rehearsal
Duration of trace: up to 30 seconds
Capacity: Stores 7 +/- 2 items
Information is maintained by repetition, organisation
Duration of trace: from minutes to years
Capacity: limit not known
Short term memory
Long term memory
Baddeley’s model of working memory The contemporary model of working memory suggests an attentional control system, the central executive, that is supported by two subsystems, one visual, one verbal
Automatic or effortful processing?
Automatic processing: the processing of information that guides behaviour, but without conscious awareness, and without interfering with other conscious activity that may be going on at the same time:
for example, driving slowly down a street (automatic processing) while looking for a specific address (conscious processing)
Levels of processing
Craik and Lockhart (1972) challenged the idea of the dual store model (STM/LTM) and suggested that rehearsal is not enough to account for memory. Too simplistic.
Craik and Lockhart believe that memories occur as a by-product of the processing of information
Proposed that shallow processing of information results in a weak memory trace, compared to deep processing which results in a stronger, more durable memory trace.
Information can be encoded at different levels, from shallow to deep:
Case (shallow level of processing):
Is the word in capital letters? BOOK
Rhyme (intermediate level of processing):
Does the work rhyme with fate? LATE
Sentence (deep level of processing):
Does the word fit the sentence:
He met a __________ in the pub? FRIEND
Levels of processing
Explicit (declarative) memory : those things that you are aware of remembering and that you can describe in words, such as your birthday, or the meaning of the word "cradle"
There are two types of explicit memory:
Episodic memory the meal you ate last night, or the name of an old classmate, or the date of some important public event.
Semantic memory is the system that you use to store your knowledge of the world. It includes our memory of the meanings of words–the kind of memory that lets us recall not only the names of the world’s great capitals, but also social customs, the functions of things, and their colour and odour.
Implicit (procedural) memory : expressed by means other than words. For example, when you ride a bike, juggle some balls or simply tie your shoelaces, you are expressing memories of motor skills that do not require the use of language. We form implicit memories without being aware that we are doing so.
How are memories stored?
Work with HM and other amnesiacs implicates the hippocampus as being crucial for memory formation
explicit memories are laid down via the hippocampus
Implicit memories are associated with the cerebellum
Neuroscience explores the synaptic changes that affect memory
Synaptic changes and memory
Hebb suggested in 1949 that memory is specific patterns of activity across a network of neurons. Synapses (connections between neurons) become more extensive during the learning. This is a "mechanism" of long-term memory.
Long Term Potentiation (LTP) an increase in a synapse’s firing potential after brief, rapid stimulation. Believed to be a neural basis for learning and memory
Fields (2005) with repeated neural firing a nerve cell’s genes produces synapse strengthening proteins, enabling long term memory to form
Retrieving a memory might involve recall, recognition or relearning
The encoding specificity principle states that memory is improved when information available at encoding is also available at retrieval.
Say "silk" five times. Now spell "silk." What do cows drink?
If you said milk that is an example of phonetic priming