cognitive Psychological: Memory

cognitive Psychological: Memory

1. models of memory

   • Duration: LTM unlimited, STM measured in seconds
     • Bahrick et al- yearbook photos, recall 70% accurate after 48 years
       • Peterson and Peterson- consonant syllables, max 18 secs
         • shepard- 50% od photos recalled after 4 months
           • evaluation
             • Marsh et al - duration may be only 2 secs if no expectation of recall.
               • Nairne et al - 96 seconds for same items across trails
                 • validity
                   • only one kind of memory (semantic memory) tested. Not actually testing duration - displacement instead
   • Capacity : LTM unlimited, STM less then 7 chunks
     • Millar- 7_+ 2, chunking
       • simon- size of chunk matters
         • evaluation
           • cowan- 4 rather then 7 chunks
             • Individual differences
               • Jacobs (1887) age differences in digit span.
                 • Applications
                   • Postcodes based on chucking
   • Encoding : LTM semantic, STM acoustic or visual
     • Baddeley- acoustic similarity decreases STM recall, semantic similarity decreases LTM recall
       • Evaluation
         • Brandimote et al- visual encoding in STM if given visual task and verbal rehearsal prevented.
           • Frost- visual coding in LTM
   • Multi Store Model (MSM)
     • Atinson and Shriffrin !1968) Structure- sensory memory, evidence from Sperling. STM- limited capacity and duration, mainly acoustic encoding. LTM- unlimited capacity and duration, mainly semantic encoding. Processes- attention and maintenance rehearsal
       • strengths: Applications- dealing with hippocampal damage. Strong evidence to support claims for duration, capacity and encoding. Includes details of structure and process. Has stimulated a lot of research which leads to increase understanding. Serial position effect ( Glanzer and Cunitz), role of hippocampus (squire et al), case studies of brain damage(eg. HM)
         • Applications: Guiding rehabilitation of people with hippocampal damage
       • Limitations: Oversimplified. STM doesn't function as a unitary story ed KF ( Shallice and Warrington). lTM is not a unitary store- eg semantic, episodic, procedural memorites, Processing more important then maintenance rehearsal- Craik and Lockhart compared shallow, phonmic and semantic processing. STM is not independent of LTM- Ruchkin et al compared words with pseudo-words involved different brain activity.
         • Validity: use of word lists. Participants often psychology students. Lab experiments ( demand characteristics, experimenter bias but well controlled).
   • The Working Memory Model (WMM)
     • Baddeley and hitch (1974) Explains why you can do two different tasks at the same time but not two similar tasks ( evidence from Hitch and Baddeley). Central executive resource allocation, small capacity. Phonological loop- phonological store and articulatory process, maintenance rehearsal. Visuo- spatial sketchpad- visual cache and inner scribe. Episodic Buffer- general store and integrates information from other stores amd also from LTM
       • Strengths: FMRI shows central executive more active when two tasks done ( Bunge et al). Explains word-length effect( Baddeley et al). Visuo-spatial sketchpad shown in visual tracking task ( (Baddeley et al) Episodic buffer shown comparing recall of related and unrelated words (Baddeley ey al). Explains memory deficits of KF and SC . Maintenance rehearsal is only an optional process. Emphasises process rather than structure.
         • Applications WMM useful in diagnosis of mental illness
       • limitations: Central exectutive doesn't actually explain anything. Central executive is probably several components ( Eslinger and Damasio). Problems with evidence from brain damaged individuals, eg no before and after comparisons.
         • validity: same validity issues as for MSM