Primary vs Secondary Memory: Understanding Decay, Interference, and Distinctions, Exams of Psychology

Download Primary vs Secondary Memory: Understanding Decay, Interference, and Distinctions and more Exams Psychology in PDF only on Docsity! Primary Memory PSY 373, Human Memory January 29, 2008 Housekeeping • Brown-Peterson experiment should be completed by Friday. • First exam will be Wed, Feb 13. • Will try to have a review session Mon, Feb 11. The Modal Model Externo! Input fo SENSORY REGISTER i : t 1 i t visvat ! ! ' LosT FROM 5R ! ' i ‘ ; ' r i os wy ‘ i SHORT-TERM STORE ' Javortorer} T | i ' VERBAL ! i ‘ ' LINGUISTIC ! 1 Lost FROM STs. wore ' ' : ‘ Lo 1 1 r y ' aut VISUAL, att, ' 1 a i Fra. 1. Structure of the memory ayatem. • Primary Memory: The set of things we’re currently aware of, including the recent past. • Secondary Memory: The set of things we could remember if we wanted to. James’ (1890) Primary memory “ The objects we feel in this directly intuited past differ from properly recollected objects. An object which is recollected, in the proper sense of the term, is one which has been absent from consciousness altogether, and now revives anew. . . But an object of primary memory is not thus brought back; it never was lost; its date was never cut off in consciousness from that of the immediately present moment. In fact, it comes to us as belonging to the rearward portion of the present space of time, and not to the genuine past.” Absolute Identification • Name a unidimensional stimulus. • When the number of stimuli is about 7 ± 2, this becomes impossible to do perfectly. • Doesn’t depend on the range of the stimuli! • An example. The central thesis of Miller (1956) Do memory span and absolute identification have anything to do with each other? Most authors would say no (e.g. Nosofsky, 1993). Others are not so sure (Brown, Neath, and Chater, in press). Chunking • Thought experiment: Learn list “absence, hollow...”, then recall the letters. You’ll get way more than 7± 2. • This is possible because you’ve recoded the letters into chunks called “words.” • Amazing feats of memorization. The Brown-Peterson Task • Brown (1958) • Peterson and Peterson (1959) • Recall trigrams after a delay. Brown-Peterson task, Methods • No shocking! • Present consonant trigram. • Count backwards by threes. • Variable delay to recall. What is the purpose of the distractor? • Prevent rehearsal. • If Broadbent’s theory is correct, then we should be looking at decay from primary memory. Decay versus interference We forget over time, but why? • Decay postulates that forgetting happens because of time per se • Interference means that other information comes in and obscures or displaces older information. • Think about our snowman (and those evil squirrels). . . or about rust. Waugh and Norman (1965) Interference vs decay in primary memory • Probe digit task: Q: 7 4 3 8 9 2 1 5 3? A: 8 • Different rate of presentation. • Allows to distinguish decay from retroactive interference. How would these results look if decay were the cause of forgetting? How about interference? Definition: Retroactive Interference • Retroactive interference is a decrement in performance attributable to subsequent learning. • Often shows up as a decrease in memory as a function of recency. Definition: Proactive Interference • Proactive interference is a decrement in performance attributable to prior learning. • Often shown as a decrement in performance with practice. • How can you distinguish from fatigue? Brown-Peterson and PI from long-term memory • No forgetting with delay for one trial. • Release from PI. • (Graphics from Delosh and Merritt, http://lamar.colostate.edu/ bclegg/PY453/STM.pdf) Release from PI results 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1 2 3 4 T rial P ro p o rt io n C o rr e c t C ontrol Experim ental Summary • Primary/secondary distinction • Decay vs interference • Proactive and retroactive interference • Waugh-Norman task and implications Things to know about the Brown-Peterson task 1. Procedure 2. Basic finding and interpretation 3. Keppel and Underwood 4. Release from PI Sperling’s results • Fig 2.2 • Whole report estimates “size” of memory at 4.5 items. • Subjects reported seeing more than they could say • Varied delay between offset of array • Fig 2.3 PSY 400 Fall ’03’s results (28 Ss) Delay (ms) % Correct 20 60.4 100 58.3 300 51.7 1000 50.6 A Graph of Fall ’03’s Data Partial report Wed Sep 03 02:38:21 EDT 2003 100.0 - Ta m ao a a a a ac T % identifi 33.333332 - 0.07 l ! ! l 10,0 356.66666 703.3333 1050, ISI fms} e Lower overall performance than Sperling? Methodological Concerns How could our results of the experiment depend on different strategies a participant might use? • What if we only concentrated on one row? What effect would this have on the curve? • How could we detect this? • What if we tended to blink when we were supposed to be looking at the array? Performance by Row of the Array 0 250 500 750 1000 ISI (ms) 0 0.5 1 1.5 2 2.5 3 N um be r C or re ct Top Middle Bottom What might be different between our data and Sperling’s? • Controlled stimulus environment (no phones ringing, darkened room). • Careful control over size of array on retina (fixed distance to screen). • What else—any uncontrolled variables? What do we mean by cognitive theory? • Empirical phenomena: Findings relating memory performance to task variables. • Theoretical explanations: Hypothesized cognitive mediators of empirical phenomena. An example • In Sperling’s partial report experiment, the rapid decrease of performance with the dependent measure is an empirical phenomenon. • Sperling’s hypothesis was that visual information is stored in iconic memory, which is subject to decay etc. • The hypothesis is not that performance decreases—that is an empirical result.