Memory

• Capacity is how much data can be held in a memory store. It is represented in terms of bits of information such as number of digits.
• Duration is how long information can be held in a memory store before it is no longer available.
• Coding is how information is changes so that it can be stored in memory.
• Sensory register

  Capacity - quite large

  Duration - 200-500 ms

  Coding - through the senses
• Short-term memory

  Capacity - 7 +/- 2 pieces of information

  Duration - 18-30 seconds

  Coding - acoustically
• Long-term memory

  Capacity - potentially unlimited

  Duration - potentially unlimited

  Coding - semantically
• Evidence for the capacity of the sensory register:

  Sterling flashed a 3x4 grid of letters onto screen for 1/20 of a second and asked participants to recall letters of one row, he found recall was high and most of the time they could remember all letters.
• Evidence for durations of sensory register:

  Walsh and Thompson found the sensory register could hold information for around 500 milliseconds.
• Evidence for coding of sensory register:

  Crowder found that the sensory register only retains information from the iconic store for a few milliseconds but 2-3 seconds for the echoic store.
• Evidence for capacity of short-term memory:

  Miller found that people can count on average 7 dots flashed in screen or recalled musical notes. Additionally, Jacob’s found the average span for letters was 7.3
• Evidence for the duration of short-term memory:

  Peterson and Peterson found that people had an 80% accuracy of the trigrams after 3 seconds but only 10% after 18 seconds. They were tested at the following intervals:

  3, 6, 9, 12, 15, 18 seconds
• Evidence for the coding of short-term memory:

  Baddeley found that participants struggled to remember acoustically similar words within 30 seconds.
• Evidence for capacity of long-term memory:

  Wagenaar found the ability to recall a large number of events, for example, recalling his own diary entries, was highly accurate.
• Evidence for duration of long-term memory:

  Bahrik et al asked 400 people to identify their friends from high-school yearbooks after 15 years. People were 90% accurate and after 48 years they were 70% accurate.
• Evidence for coding of long-term memory:

  Baddeley found that participants struggled to remember semantically similar words after 30 seconds. However, research has said that LTM may not be exclusively semantic, Frost suggested it might also be visual.
• Strengths of the Multi-store model of memory:

  • The multi-store model was the first model of memory which considered a cognitive explanation for memory. It suggested a theoretical framework for how memory may work in the human mind.
  • There is research to support from case studies such as Clive Wearing. This study suggests that short and long term memory have separate stores.
• Weaknesses of the Multi-store model of memory:

  • One problem with the model is that it is over-simplified by assuming that STM and LTM are both single stores. The working memory model, a newer theoretical model which suggests that short-term memory is split into several stores including one for visual processing and another for sound-based information.
  • The multi-store model mainly focuses on structure i.e the idea that there are separate stores of memory. However less research has been conducted into the processes that occur between the stores.
• Baddeley and Hitch believed there was more than one single STM store. They believed it was an active store holding several pieces of information at once.
• Working Memory can be defined as the focus of consciousness - holding information currently important. This model is not a replacement of the MSM but an elaboration on the original ideas of STM.
• The working memory model suggests that there are four stores to short-term memory.
• The first store of short-term memory is the central executive and its role is to direct attention to particular tasks. it determines which store (slave system) needs to process the information. It has a very limited capacity as its role is simply to allocate tasks.
• One of the slave systems is the Visio-spatial sketchpad which processes visual information such as what you see and spatial information i.e. the relationship between objects in a space.
• The Visio-spatial sketchpad is further split into two sub-components called the visual cache which processes the visual information e.g. shapes and colours, and the inner scribe which stores the arrangement of objects in the visual field.
• Another slave system is the phonological loop which processes sound-based information.
• The phonological loop is further split into two sub-components, the phonological store which temporarily holds auditory information and the articulatory rehearsal loop which is your inner voice which is a form of maintenance rehearsal, where auditory information can be repeated.
• The newest store of the working memory model is the episodic buffer. This store is an extra storage space for information which cannot be held in the central executive, due to its limited capacity. It is also used to bind and integrate the information from the two slave-systems, putting the information together into logical and time-relevant order. From here information can also travel into long-term memory.
• Strengths of Working Memory Model:

  • There is supporting from case studies for the existence of the phonological loop and visual store. Shallice and Warrington’s case study of KF who had suffered brain damage and had poor ability for verbal information but could process visual information.
  • There is supporting evidence for the visual-spatial sketchpad.
  • There is supporting evidence for the central executive.
• Weaknesses of the Working Memory model:

  • The explanation of the central executive is shallow and so its effect on memory is questionable. Cognitive psychologists suggest that the central executive is unsatisfactory and doesn't really explain anything. It needs to be more clearly specified than just being 'attention'.
• There are three different types of long-term memory which are responsible for processing different types of information. This is something not accounted for by either of the models of memory.
• The first type of long-term memory is episodic memory. This is a type of explicit memory which includes the memory of personal experiences e.g. your first day of school. These memories have three specific elements, including details of the event, the context and emotions.
• The strength of episodic memories is determined by the strength of the emotions experienced when the memory is coded. Episodic memories are associated with the hippocampus.
• Semantic memory is associated with long-term memories for facts/ general knowledge and the rules of language. For example, the names of capital cities. These types of memories often first start as episodic memories, as we acquire knowledge based on personal experience.
• Like episodic memories, the strength of semantic memories are determined by the strength of emotions. However, semantic memories are generally stronger in comparison and associate with the temporal lope. Both semantic and episodic memories are conscious memories, otherwise known as explicit.
• Finally, procedural memories are memories of skills/ actions or muscle memories, for example reading and writing. They are unavailable for conscious inspection and therefore difficult to explain verbally. They are also more resistant to forgetting amnesia. They reside in the motor cortex region of the brain and are also associated with the limbic system and Basal Ganglia. This type of memory is an unconscious memory, known as implicit memory.
• Strengths of long-term memory:

  • There are case studies of brain damaged patients to support this. The case of CW and HM showed that, although both men had problems with their episodic memory, their semantic and procedural memories were intact.
  • The research into LTM has real-world application. This is because it allows psychologists to target certain kinds of memory to improve people's lives. Specific treatments can be developed to improve different types of LTM.
• Weaknesses of long-term memory:

  • Some psychologists argue that there may only be two types of memory. For example, Cohen and Squire argue that semantic and episodic memory are both consciously recalled and are held in the same store. They call this declarative memory.
• Forgetting can be defined as an inability to recall information.
• Interference theory:


  One theory of why we forget is interference theory. This is when long-term memory becomes confused with or disrupted by other information during coding, leading to inaccurate recall. The theory suggests that we forget because the two types of information are similar to each other.
• Interference theory:


  Proactive interference is when you cannot learn a new task or piece of information because of an old one. What we already know is interfering with what we are currently learning. For example, we forget our new boyfriends name because the name of our old boyfriend interferes with it.
• Interference theory:


  Retroactive interference is when you forget a previously learnt task or piece of information, due to the learning of a new one. In other words, later learning interferes with earlier memories. For example, we can't remember our old address because we have moved to a new house.