Transcript Chapter 7
Chapter 7 In this chapter, we discuss some of the data collected by researchers trying to solve the problems of memory structures and processes. The chapter is divided into two sections – short-term memory and long-term memory. SHORT-TERM MEMORY - Neurocognition and STM Capacity of STM The Coding of Information in STM Retrieval of Information from STM LONG-TERM MEMORY - Neurocognition and LTM LTM: Storage and Structure Very Long-Term Memory (VLTM) Autobiographical Memories SHORT-TERM MEMORY Peterson and Peterson (1959) subjects were read a three-letter cluster and asked to recall it after varying periods. During these periods (between hearing the letters andattempting to recall), subjects counted backward by threes from a threedigit number presented immediately after the three-letter cluster, as here: Experimenter says: CHJ/506 Subject responds: 506, 503, 500, 497, 494, and so on STM - Peterson & Peterson Results: Recall seriously eroded in the absence of rehearsal. experiment demonstrated that our capacity to store information in a temporary memory bank is severely limited and susceptible to forgetting if we do not havethe opportunity to rehearse the information. Their experiment represented a turning point in our experimental conceptualization of short-term retention (2 memory banks). 2 memory banks? 1. Casual observation suggests some things are remembered for a short time and others for a long time 2. Physiological studies indicate that short term functions can be interrupted, while long term functions seem to remain intact 3. Psych. experiments suggest retrieval of some info is characteristic of a shortterm function while other is NEUROCOGNITION AND STM Brenda Milner (1966) The case of H.M. severe epilepsy, bilateral surgical excision (of the medial temporal region) was done procedure removed parts of the temporal lobe, including the hippocampus. H.M. became profoundly amnesic and could not seem to store new information in LTM; his STM was unimpaired. STM Theory Hebb’s Dual Trace Theory If original activity continues for some time, structural changes at the synaptic contacts among cells could carry the memory thereafter. These structural changes would correspond to long-term memory, and the earlier continued identified with short term memory STM Capacity Magic Number 7 +/- 2 (Miller, 1950’s) Chunking (coding single units into larger units) can greatly expand STM capacity doesn’t work without activating LTM (provides the framework) FBI, PHD, TWA, IBM easier than FB, IPH, DTW,... CODING OF INFORMATION IN STM - Auditory Code predominate method in STM, even if info presented visually (research) - Other research suggests visual or semantic codes LOOK UP! Research on the Duration of STM The Brown-Peterson Paradigm Research on the capacity of STM Research on the Acoustic Code in STM Research on Verbal Rehearsal and STM The Serial Positions Effect Searching through STM: Serial search S. Sternberg LTM General findings: Relatively permanent storage Unknown capacity Organized as seen in Free Recall Tasks LONG-TERM MEMORY Some experiences are remembered better than others, such as, exciting, egoinvolving are, or even traumatic experiences seem to stick in memory better than complicated political theories. Neurocognition and LTM Where do memories reside? (PET) Frontal area involved in deep processing of info Hippocampus and thalamus involved in formation of memories Cerebral Cortex - permanently stores memories Conclusion - very generalized, all over Neurocognition and LTM How does brain store info? Donald Hebb - STM info converted to LTM if active for long enough period of time. LTM is chemical and/or structural change LONG-TERM MEMORY SUGARCOATED GOLDEN MEMORIES: For example: animal studies have indicated that blood stream of epinephrine (adrenaline), which has now been demonstrated to enhance consolidation of a memory (McGaugh, 1990). It is likely that epinephrine does not directly stimulate the brain’s synapses (there is matter of crossing the blood brain barrier), but converts stored glycogen to glucose (a sugar), thereby raising the blood level of glucose, which nourishes the brain. LTM: Storage and Structure CODES: In LTM, information is clearly coded acoustically, visually, and semantically. Multidimensional coding little research on taste, smell, and touch, but probably also coded this way LTM: Storage and Structure Organization: assumed some order to LTM network of interrelated and associated info, very complex new info is recorded in existing info LTM: Storage and Structure Capacity and Duration Huge, Almost Permanent Loss of recall can be due to interference or decay Very Long Term Memory VLTM - memories more than 3 months old Research on yearbook pictures showed: recognition about 90% correct over 34 years Name recognition and name matching declined after 15 yrs sharp decline in recogniton and recall after 35 yrs. May reflect a degenerative process of aging Very Long Term Memory Research on memory for Spanish language decline the most over first 3 yrs, then relatively stable over 30 yrs. Much of orignially learned info still usable after 50 years - suggested a “permastore” LTM: Storage and Structure Autobiographical Memory Memories of your past history Hard to study objectively - why? Linton’s “Journal” study - found linear forgetting, and 2 types - interference and decay Flashbulb memories - special mechanism? Fallability of Memory Eyewitness Testimony and False Memory memory is reconstructive “recovered Memories” can be false memories very susceptible to change