Storage: Retaining Information

Transcription

1 PSYCHOLOGY (8th Edition, in Modules) David Myers PowerPoint Slides Worth Publishers, Storage: Retaining Information Module 26 2 Storage: Retaining Information Storage: Retaining Information Sensory Working/Short-term Long-Term Storing Memories in the Brain 3 Psychology 7e in Modules 1

2 Storage: Retaining Information At the heart of memory is storage. Three stores of memory are shown below: Sensory Working Long-term Events 4 Sensory Sensory Working Long-term Events 5 Whole Report Sperling (1960) R G T F M Q L Z S Recall R T M Z (44% recall) 50 ms (1/20 second) The exposure time for the stimulus is so small, that items cannot be rehearsed. 6 Psychology 7e in Modules 2

3 Partial Report S X T J R S P K Y 50 ms (1/20 second) Low Tone Medium Tone High Tone Recall J R S (100% recall) Sperling (1960) argued that sensory memory capacity was larger than what was originally thought. 7 Time Delay A D I N L V O G H Time Delay Low Tone Medium Tone High Tone Recall N (33% recall) 50 ms (1/20 second) 8 Sensory The longer the delay the greater the memory loss. Percent Recognized Time (Seconds) 9 Psychology 7e in Modules 3

4 Sensory Memories Duration of sensory memory differs for different senses. Iconic 0.5 sec. long Echoic 3-4 sec. long Hepatic < 1 sec. long 10 Working Sensory Working Long-term Events 11 Working Working memory, a new name for short-term memory, has limited capacity (7±2) and short duration (20 seconds). Sir George Hamilton observed that he could remember up to 7 beans thrown on the floor accurately. If there were more beans he resorted to guessing. 12 Psychology 7e in Modules 4

5 Capacity The magical number seven plus or minus two: some limits on our capacity for processing information (1956). Ready! M U T G I K T L R S Y P You should be able to recall 7±2 letters. George Miller 13 Chunking Capacity of working memory may be increased by Chunking. F-B-I-T-W-A-C-I-A-I-B-M FBI TWA CIA IBM 4 chunks 14 Duration Brown/Peterson and Peterson (1958/1959) measured the duration of working memory by manipulating rehearsal. CHJ MKT HIJ CH?? Duration of working memory is about 20 sec. 15 Psychology 7e in Modules 5

6 Working Duration 16 Long-Term Sensory Working Long-term Events 17 Long-Term Unlimited capacity store. Estimates on capacity range from 1000 billion to 1,000,000 billion bits of information (Landauer, 1986). R.J. Erwin/ Photo Researchers The Clark s nutcracker can locate 6,000 caches of buried pine seeds during winter and spring. 18 Psychology 7e in Modules 6

7 Feats 19 Stores Feature Sensory Working LTM Copy Phonemic Semantic Capacity Unlimited 7±2 Chunks Very Large Duration 0.25 sec. 20 sec. Years 20 Storing Memories in the Brain Wilder Penfield (1967) through electrical stimulation of the brain concluded that old memories were etched in the brain. Loftus and Loftus (1980) reviewed Penfield's data and showed that only a handful of brain stimulated patients reported flashbacks. Lashley (1950) using rats, suggested that even after removing parts of the brain the animals retained partial memory of the maze. 21 Psychology 7e in Modules 7

8 Synaptic Changes Kandel and Schwartz (1982) Showed, in Aplysia, that serotonin release increased from neurons after conditioning. Photo: Scientific American 22 Synaptic Changes Long-Term Potentiation (LTP) refers to synaptic enhancement after learning (lynch, 2002). Increase in neurotransmitter release or receptors on the receiving neuron indicates strengthening of synapses. Both Photos: From N. Toni et al., Nature, 402, Nov Courtesy of Dominique Muller 23 Stress Hormones & Heightened emotions (stress related or otherwise) make for stronger memories. Continued stress can disrupt memory. Scott Barbour/ Getty Images 24 Psychology 7e in Modules 8

9 Storing Implicit & Explicit Memories Explicit refers to facts and experiences that one can consciously know and declare. Implicit memory involves learning an action, and the individual does not know or declare what she knows. 25 Hippocampus Hippocampus a neural center in the limbic system that processes explicit memories. Weidenfield & Nicolson archives 26 Anterograde Amnesia After losing his hippocampus in surgery, patient HM remembers everything before the operation but cannot make new memories. We call this anterograde amnesia. Anterograde Amnesia (HM) Intact No New Memories Surgery 27 Psychology 7e in Modules 9

10 Implicit HM is unable to make new memories that are declarative (explicit) but he can form new memories that are procedural (implicit). A B HM learnt the Tower of Hanoi (game) after his surgery. Each time he plays it he is unable to remember the fact that he has already played the game. 28 C Cerebellum Cerebellum a neural center in the hindbrain that processes implicit memories. 29 Psychology 7e in Modules 10