Memory involves retaining, retrieving, and using information about stimuli, images, events, ideas, and skills after the original information is no longer present.
It's an active process where past experiences impact current thoughts or behaviors.
Modal Model of Memory
Developed by Atkinson and Shiffrin (1968).
Includes three types of memory:
Sensory Memory: Holds incoming information for a fraction of a second.
Short-term Memory: Holds 5-7 items for about 15-20 seconds.
Long-term Memory: Holds a large amount of information for years or decades.
Control processes are active processes controlled by the person, such as:
Strategies of attention (selective attention).
Strategies to make stimuli more memorable (cues, heuristics).
Rehearsal: Repeating information.
Sensory Memory
Retains effects of sensory stimulation for brief periods.
Holds a large amount of information for initial processing, but decays quickly.
Allows us to experience the world as a continuous stream.
Early evidence includes persistence of vision (e.g., sparkler's trail of light).
Sperling (1960) measured capacity and duration using flashed letters.
Whole report method: Participants reported an average of 4.5 out of 12 letters (37.5%).
Partial report method: Participants reported an average of 3.3 out of 4 letters (82%).
Delayed partial report method: Performance decreased, remembering 1 out of 4 (25%) after a 1-second delay.
Conclusion: Sensory memory is short-lived, less than a second.
Iconic memory: Brief sensory memory of visual information lasting 200-500 milliseconds, holding up to 12 items.
Echoic memory: Brief sensory memory of auditory information lasting less than a second, possibly up to 3-4 seconds.
Visual masking can disrupt iconic memory. Presenting a visual stimulus (mask) shortly after the initial stimulus.
Auditory masking, noise interference, and rapid presentation can disrupt echoic memory.
Short-Term Memory
Stores small amounts of information (5-7 items) for a brief period.
Includes new information from sensory stores and old information from long-term memory.
Peterson & Peterson (1959) measured duration by having participants recall letters after counting backward.
After 3 seconds, performance was at 80%; after 18 seconds, it was at 10%.
Decay is the vanishing of a memory trace due to time and competing stimuli.
Conclusion: Short-term memory lasts about 15-20 seconds when rehearsal is prevented.
Capacity is measured by digit span; typical result is 5-7 items.
George Miller (1956) found capacity to be 7 +/- 2 items or “chunks”.
Chunking: Combining small units into larger meaningful units.
Strong association within chunks, weak association across chunks.
Ericsson et al. (1980) demonstrated that with training, a person could remember up to 79 digits by chunking them into meaningful units.