Visual Sensory Memory Part 2

Results of Sternberg Task ___________________________________________ Ideal 650 550 Positive Negative Pooled 450 350 0 1 2 3 4 5 6 Linear Increase with a slope of about 40 ms Implications: 1. We spend average of 40 ms per item a. What does that say about scanning? 2. No differences between Yes and No trials Question: How do these data compare to visual search in attention? Results of Sternberg Task ___________________________________________ Your Data:  Present:  Absent: m = 65.4 ms m = 69.0 ms 1200 Mean RT 1100 1000 Present Absent 900 800 700 600 1 3 Search set 5 Why have an exhaustive search? ___________________________________________ To avoid switching costs Sternberg: Homonculus does all comparisons, then looks at readout (all serial). EX:  Mainframe computers  Going to dinner with a large group  Paying Bills ___________________________________________ Other important issue Additivity Manipulates multiple variables simultaneously, and only observed additive effects. What does that mean? EX: Destitute = Lonely + Sleepy Forgetting in STM: Decay vs. Interference ___________________________________________ Decay –  As time passes, information gradually leaves STM Interference –  New data pushes old info out of STM  Old data in STM makes it harder to learn new info ______________________________________________ Supports Decay Theory Supports Interference Theory Brown-Peterson Serial Position Effects ______________________________________ What about trying to eliminate interference?  Cockroach study  Sleep Study  Anesthesia Further Evidence supporting Interference ___________________________________________ Waugh & Norman  Manipulated rate of presentation  Predictions? Crowder  Suffix Effect  Predictions? ___________________________________________ Other important interference tidbits Interference is a two-way street 1) New items interfere with old and 2) Old items interfere with new  Phone numbers  Parking spaces  Release from PI (retroactive) (proactive) Answers to the Key Questions ______________________________________________ Capacity Sensory Memory Very large STM Duration Very short Don’t get me started Coding Physical (analog) Largely physical, but not entirely Search Pass Serial; exhaustive Forgetting Decay/ Interference Decay, RI, and PI 7 ± 2 chunks LTM Baddeley's Working Memory Model ___________________________________________ Why revamp STM? 1. Difficult to empirically dissociate STM from LTM a. Sensitive to many of the same manipulations EX: Write down the names of every President 2. Case study evidence a. Some case studies show really bad performance on some STM tasks, but normal performance on other STM tasks. 3. STM is dynamic a. Not a passive storehouse of information; it manipulates information, as well i. Release from PI ii. Memory Span Working Memory Model ___________________________________________ Central Executive      Retrieves information from LTM Transfers information into LTM Reasoning, Decision Making Language Comprehension Response Initiation Phonological Loop VisualSpatial Sketch Pad Short-term vs. Working memory ___________________________________________ Phenomenologically Similar Both refer to the conscious part of memory. Structurally distinct STM – unitary A lone box fighting for justice in an uncaring world WM – tertiary Three components working together Conceptually distinct STM – Contents oriented How much information is in there? How is information lost? How do we transfer information to LTM? WM – Process oriented How do we represent information? How do we manipulate information? Codes in Working Memory ___________________________________________ 1) Phonological codes (Phonological Loop)  Phonological Similarity Effect 2) Visual Codes (VSSP)  Rotation Studies  Other Imagery Tasks 3) Semantic codes (Central Executive)  Release from PI ______________________________________________ Q: Didn’t we say simpler theories were better? Isn’t STM (one box) simpler than WM (three distinct parts)? A: Yes. WM is more parsimonious, but parsimony must be weighed against the ability to: a) Explain existing data b) Make new predictions Dual Task Experiments ___________________________________________ STM Because STM is unitary, it predicts that multiple tasks should affect performance in the same way regardless of type. WM WM consists of dissociable modules. Therefore, dual tasks should only affect performance if both tasks utilize the same module. ___________________________________________ Results consistent with WM framework  Significant cost when performing two tasks that utilize the same modality (V-V or A-A).  Minimal costs when performing two tasks that draw on different modalities (e.g., V-A). Unique Predictions of WM framework ___________________________________________ Prediction #1 If: CE uses a semantic code and PL uses a phonological code Then: articulatory suppression should affect phonological processing but not comprehension. Evidence:  AS abolishes the phonological similarity effect  AS does not affect comprehension ______________________________________ Prediction #2: If: PL is like a continuously recycling piece of audio tape Then: STM capacity should be affected by both the length and the number of the to-be-remembered items. Evidence:  Word Length Effect  Cross-cultural differences in IQ Baddeley, Thomson, & Buchanan (1975) ___________________________________________ Intro: 1) Why is ‘7  2 chunks’ a problematic characterization of STM capacity? 2) What are primary memory and secondary memory? 3) Reading rate predicts memory: why is that not sufficient proof that chunks do not determine STM capacity? Method & Results: Exp Control Var I Frequency II Category III # of syllables IV Phonemes V Same VI Categ; Famil. VII # of syllables VIII # of syllables Exper Var # of syllables # of syllables Artic Time Artic Time Visual presentation # of syllables, order Artic Supp Results Short > Long Short > Long Short > Long Short > Long Short > Long; ↑Artic rate ↑Mem Short > Long; linear slope Short > Long; AS abolished WL AS; Modality Short > Long; AS abolished WL in both modes Baddeley, Thomson, & Buchanan (1975) ___________________________________________ Implications: 1) Why do the modality data matter? 2) What professor has the largest digit span in the psychology department? 3) How is information represented/coded in STM? 4) How best to describe STM capacity? 5) Why doesn’t recency show an effect of word length? ___________________________________________ Problems with the Working Memory Model 1. Not much known about VSSP 2. Central Executive "Area of Residual Ignorance"  Why is that a problem?