375: Sensory and Primary Memory

1. Iconic Memory
1. Properties
1. Large capacity: can be pretty accurate on arrays up  to 20 characters
2. Brief Duration
3. Representation: you don't process semantically
4. lost through decay or masking
1. When does decay start?  Stimulus onset or stimulus offset?
1. Found that the longer a picture was shown (up to 200 milliseconds) the worse a person would do on a memory task.  
2. This shows that decay begins at onset
2. Masking
1. Erases iconic memory
2. Example
1. Showed 2 similar pictures flashing back and forth with a gray screen in between the flashes.  The gray screen would make it so that you don't notice a dissimilarity between the pictures.  The gray screen in this case works as a mask.
1. Without the gray screen the dissimilarity is extremely obvious but can be very difficult to detect with the gray screen in between.
2. Echoic Memory
1. Like iconic but auditory instead of visual
2. Duration ~ 250 ms
1. How can varying the onset of a mask show this?
3. Capacity?
4. There is much less research on echoic memory than iconic memory
3. Primary Memory (William James)
1. Input TO sensory memory TO primary memory (stm) TO secondary memory (ltm)
1. Primary and secondary go back and forth
2. Definition: Primary memory is what you're working with in the here and now (i.e. at the front of your mind)
3. 2 Theories for how Primary Memory works
1. Short-term memory
2. Working memory
4. Model Model: refers to the popular stage theory of memory
1. Information is thought to have to pass through sensory, then short-term memory on its way to long-term memory
2. The only way to retain STM is through rehearsal
3. Allows us to ask...
1. What is the capacity and how is info represented in STM
1. Capacity
1. Chunking
1. If you organize information into meaningful units it's called chunking
2. You can remember about 7 chunks (+ or - 2)
3. This shows us that short term memory is coded semantically 
2. Model model breaks down for non-verbal information since you can't rehearse it
5. Working Memory Model
1. Phonological Loop TO Central Executive TO Visio-spatial Sketchpad (moves forwards and backwards)
1. Example of trying to memorize words that are similar vs words that are similar and rhyme
2. It is harder to remember a list of words that rhyme
1. Phonological Loop
1. 2 components
1. Phonological Store: stores about 2 seconds of auditory info
1. Info can enter the phonological store from the environment
2. Articulatory Control Process: Info can enter the phonological store via the Articulatory control process; it is literally the process of talking to yourself
2. People who talk faster have larger capacity
3. anyone has small capacity for long words
4. Since the store is auditory, you should confuse words that sound alike
5. If you busy the articulators the articulatory control process can't put new info into the phonological loop and you lose that information
2. Visuo-spatial sketchpad
1. This is where you store visual or spatial info.  (similar to mental imagery)
2. What do you do if you can't code acoustically?
3. Example: 
1. We listed 4 different lists, the first 3 were different fruits the last was occupations
1. As you continue with different fruit lists you get worse and worse (proactive interference)
4. 3 ways to code information
1. Acoustic
2. Visual
3. Semantic
4. Another Component
1. Episodic buffer
1. Allows phonological loop and visuo-spatial sketchpad to interact
2. Allows for interaction w/ LTM
3. Central Executive
1. Cognitive supervisor and/or scheduler, integrating info from multiple sources and making decisions about strategies to be used on tasks
2. If you have damage to frontal lobe (where the executive is) all other types of primary memory will be impaired