Lecture 14 - Memory and the senses Flashcards
(26 cards)
What is iconic memory?
A brief visual representation that preserves rich visual detail (e.g., spatial position, colours), lasting under 1 second
How did Sperling (1960) demonstrate the richness of iconic memory?
Using the partial report procedure:
- Participants saw 12 letters briefly
- If cued immediately to recall a specific row, they could recall it
- This suggests they had stored the entire array temporarily
How do we know iconic memory is visual and brief? (Sperling, 1963)
A visual mask (bright light before/after) disrupted recall, implying:
- Iconic memory stores visual data
- It’s sensitive to interference and short-lived (~0.5s)
If iconic memory is so brief, how is visual detail preserved?
Some information is transferred to short-term memory, where it can be stored longer for further processing
What method measures short-term visual memory capacity?
Visual change detection tasks (Luck & Vogel, 1997):
- Detect changes in patterns of coloured shapes
- Performance declines after ~3-4 items
What neural evidence supports this memory limit?
McCullough et al. (2007) used EEG to measure contralateral delay activity:
- Activity increased up to 4 items, then plateaued
- Confirms limited capacity of visual short-term memory
What are two major theories about how visual memory stores information?
1) Discrete slots (Luck & Vogel, 1997; Rouder et al., 2008): Small number of items stored precisely, rest forgotten
2) Continuous resource (Bays & Husain, 2008): All items stored, but varying precision (some sharp, others fuzzy).
Both may be partly correct
What is the ‘continuous feature production task’?
- Participants are shown several items, wait 1 second, then reproduce features (e.g., colour, location)
- Performance drops beyond 3 items, suggesting guessing
How is visual short-term memory influenced by knowledge of the world?
Ngiam et al., 2023: Our perception is informed by prior knowledge, not just raw input
What do Cohen, Dent & Kanwisher (2016) suggest about vision and memory?
- We don’t remember exact images: we store vivid instances of familiar categories (e.g., a dog), then use emsemble statistics to fill in the rest
What task shows we extract conceptual info from fast vision?
Rapid Serial Visual Presentation (RSVP):
- People can detect whether a specific object was shown
- Implies conceptual info is extracted, even if iconic memory is overwritten (Potter, 2017)
Is visual short-term memory purely visual?
No: Morey & Bieler (2013) show it includes non-visual (conceptual) features
What are the key features of iconic memory?
- Automatic access
- Duration: < 500ms
- Capacity: rich but bried
- Strictly visual (e.g., disrupted by visual tasks)
What are the key features of visual short-term memory?
- Assessed via transfer from iconic memory
- Duration: seconds
- Capacity: ~2-4 items
- Not strictly visual, may include conceptual or categorical encoding
Can sensory detail be preserved over time?
- Yes, but only briefly unless processed further
- Rubin & Kontis (1983) suggest reconstruction from long-term knowledge may also play a role
Duration of iconic memory?
< 1 second
Study using partial report to reveal iconic memory?
Sperling (1960)
What disrupts iconic memory?
Visual masks (Sperling, 1963)
Capacity of visual STM?
3-4 items (Luck & Vogel, 1997)
EEg study confirming this capacity?
McCullough et al. (2007)
Two theories of visual STM storage?
Discrete slots vs. continuous resource
Study supporting continuous resource theory?
Bay & Hussain (2008)
Study on ensemble statistics and dog perception?
Cohen, Denett & Kanwisher (2016)
What task shows rapid conceptual extraction from vision?
RSVP (Potter, 2017)
