Memory Codes

• Auditory, visual, tactile, gustatory, olfactory, semantic, verbal (words)

Sensory vs. STM

• Sensory memory– ICON – visual format or visual code– ECHO – acoustic code– Generally, code is the same as the sense– E.g., Touch sensory memory tacticle

Sensory vs. STM

• What is the code in STM?

• Example study (Conrad, 1964)– Used the span task with letters (presented

visually)– Very accurate, but occasionally make

mistakes he studied the mistakes (when people remember the wrong letter)

Confusion mistakes (confusions)

• When you remember the wrong letter,– The wrong letter could look like the letter you

saw (visual confusion)• E.g., saw L I

– The wrong letter could sound like the letter you saw (acoustic confusion)

• E.g., saw P T

Results

• The vast majority of the mistakes were acoustic confusions

• Conclusion STM involves acoustic coding

• More generally, acoustic coding is common in short-term memory

Atkinson-Shiffrin model (1968)

• Model of different memories, their codes, and the processes that access the memories

• 3 kinds of memory:– Sensory memory– Short-term memory– Long-term memory

Flow of memory

• Stimulus from environment stimulus represented in sensory

memory (small capacity, extremely brief duration, code is related to the sense [sensory modality])

stimulus represented in STM (limited capacity, duration up to about 30 seconds, primarily acoustic code)

Flow (cont.)

stimulus represented in LTM (infinite capacity [unlimited], infinite duration, variety of codes)

• Aka, the “modal model”

• See p. 83 for the diagram of this information processing model

Another model of short-term memory

• Emphasizes the “working” aspect of memory

• Called the Working Memory Model (Baddeley, 1986)

• Three components to short-term memory: phonological loop, visuospatial sketchpad, central executive

Phonological loop

• Hold small amount of information in terms of the way it sounds (acoustic coding)– Phonological sounds come from your

language– Acoustic = any sounds

• Can hold about 2 seconds worth of phonological information at a time (like an audiotape) [capacity]

Visuospatial sketchpad

• Like a drawing tablet, with only so many things drawn at a time (limited capacity, visual code)

• Holds not only the visual information (what things look like), but also how they are arranged (spatial information)

Central executive

• Monitors, keeps track of, arranges information, etc. within the phonological loop and the visuospatial sketchpad

• E.g., central executive involved in moving information from phonological loop to LTM

• Also, converts information from one code to another

Diagram of WM Model

Phonological Loop VSSCentral

Executive

Current state of A-S & WM Model

• A-S: still most commonly accepted model of memory, including outside of cognitive psychology, and out into general public

• WM: used outside of cognitive psychology, especially in neuropsychology or neuroscience