Memory

• Capacity


  A measure of how much can be held in memory
• STM


  • Limited, less than 7 chunks
• LTM


  • Possibly limitless
• Key study: Capacity of STM by Jacobs 1887

  He found the average span for digits was 9.3 items and 7.3 for letters. He says that more digits were recalled as there's only 9 of them and there was less remembrance for the letters as there are 26 of them.
• Duration


  A measure of how long memory lasts in the brain
• STM


  • Few seconds to a minute
• LTM


  • 2 minutes to 100 years
• Key study: Peterson and Peterson 1959


  Aim: investigate duration of STM

  Procedure: Conducted a lab experiment to test 24 students over 8 trials. Each trial gave a consonant syllable and a 3-digit number (ex. THX 512). Participants recalled the consonant syllable after a retention interval (3, 6, 9, 12, 15, 18 seconds) during which they counted backwards from the 3-digit number presented.

  Findings: On average, recall within 3sec. was 90%, within 9sec. 20% and within 18sec. only 2%

  Conclusion: When verbal rehearsal of the consonant syllable is prevented duration of STM is very short
• Key study: Bahrick et al 1975


  Aim: investigate duration of LTM

  Procedure: He tested over 400 people, aged 17-74, for their memory of high school classmates. A photo-recognition test they identified high school yearbook images of their classmates from 50 photos. In a free-recall test they listed names of classmates in their graduating class.

  Conclusion: Duration of LTM is much longer than STM however if the information is not used it will disappear.
• Coding


  The way information is changed so that memory can be stored as visual, acoustic (hearing), semantic (meaning)

  
• STM


  • Acoustically
• LTM


  • Semantically
• Key study: Baddeley 1966


  Aim: to investigate coding in STM and LTM

  Procedure: In a lab experiment, he gave participants lists of words that were acoustically similar (sounded alike) or dissimilar and lists of words that were semantically similar (synonyms) or dissimilar.

  Results: STM codes acoustically and LTM codes semantically.

  Conclusion: STM uses acoustic coding whereas LTM uses semantic coding.
• Multi-store model (MSM) - Atkinson and Shiffrin


  A cognitive explanation of memory based on 3 separate notes, and the processes that transfer information between these stores.

  
• Sensory register (store)


  • Information collected by your senses. Capacity of the sensory register is large, duration is brief. Method of coding depends on the sense
• Attention (process)


  • Paying attention to one of the sensory stores, this transfers data to STM
• STM (store)


  • Limited duration, limited capacity. Information is usually coded acoustically.
• Maintenance rehearsal (process)


  • Repeating information to transfer data held in STM to LTM
• LTM (store)


  • Potentially unlimited in duration and capacity, information is coded semantically.
• Retrieval (process)


  • To get back information from LTM it needs to pass through STM.
• Sensory register


  Coding: Coded by the nervous system depending on which sense is used/activated. Each sensory input has a separate sensory store.

  Capacity: Large capacity. To study this, artificial experiments have to be done – low external validity.

  Duration: Each store has a different duration, but almost all decay quickly because the brain needs to respond to live stimulation constantly.
• Working model memory - Baddeley and Hitch 1974


  An updated version of STM
• Central executive


  • An attention process to monitor incoming data from the senses and LTM. Determines how the slave systems (below) are allocated to tasks. Has limited capacity and can't store data.
• Episodic buffer


  • Extra storage; sends information to LTM. Has limited capacity
• Phonological loop (PL)


  • Deals with auditory information and preserves its order. It's subdivided into phonological store (words you hear) and articulatory process (rehearsal).
• Visuo-spatial sketchpad


  • Responsible for visual/spatial information. Subdivided into visual cache (storage about colours and form) and inner scribe (spatial relationships between objects)
• Priming


  Automatic enhanced recognition of specific stimuli ex. exposure to the word 'yellow' the person is more likely to think of a banana
• Episodic


  Factual/meaningful memories: personal experiences that have – specific details of the event, the context and the emotion.
• Procedural


  Motor skills which through repetition and practice become automatic - an unconscious recall.
• Semantic


  General knowledge: function of objects, mathematics, language. Start off as episodic memories but it becomes semantic.
• Interference


  Where 2 lots of information become confused in memory, and it's more likely to occur when the two pieces of information are similar/response
• Retroactive


  Is where new learning affects recall of old. Ex. your a-level teacher may forget the names of students from previous years as they have learned the names of students in their new classes
• Proactive


  Is where old learning affects recall of new information. Ex. you can speak French after studying it for GCSE and decide to start learning Spanish but you find this difficult as you French interferes
• Key study: Mūller and Pilzecker 1900


  Procedure: Performed a laboratory experiment where participants had 6 minutes to learn lists of nonsense syllables. After a retention interval they were asked to recall the syllables.

  Findings: Recall was poorer when participants were given a task in between learning and recall. So the new task interfered with prior learning of the syllables.
• Key study: Underwood 1957


  Procedure: Analyzed studies in which participants' memory for numerous lists of words were tested after 24 hours.

  Findings: If participants memorized 10 lists or more they remembered only 20%. If they only learned just 1 list, recall was 70%. He concluded that when learning a series of lists, words in later lists are not learned as well as words encountered later on.

  
• Proactive interference


  Where old learning affects recall of new information
• Proactive interference


  • You can speak French after studying it for GCSE and decide to start learning Spanish but you find this difficult as your French interferes
• Retroactive interference


  Where new learning interferes with the recall of old information
• Procedure: Mūller and Pilzecker 1900


  Participants had 6 minutes to learn lists of nonsense syllables, then after a retention interval they were asked to recall the syllables
• Procedure: Underwood 1957


  Participants' memory for numerous lists of words were tested after 24 hours