R.G. Bias | | Name that tune. Song title? Performer(s)? 1

R.G. Bias | | Memory and Cognition “The Knower” 1/27/10 2

R.G. Bias | | Objectives After this class you will be able to (it is my hope!): -Have an (increased?) understanding of how psychologists and information scientists develop models of human performance -Be able to state the differences between short- and long-term memory -Understand how human memory and cognition limitations influence the design of information systems

R.G. Bias | | We’re talking about “the knower”  What do we know about humans?  We are strong in our knowledge of anthropometry -- the measurement of the size and proportions of the human body.  But these days – in “the information age” – we are way more interested in our cognitive selves.

R.G. Bias | | On Monday, we were talking about Sensation and Perception  “Sensation” is the transformation of physical energy into nerve impulses to the brain.  “Perception” is the interpretation of – the imposing of meaning upon – those sensations, including the influence of beliefs, attitudes, biases, moods,....  The fact of “ambiguous images” shows the influence of these non-stimulus (“top-down”) factors – the importance of CONTEXT on perception.  We (re)learned a little ear and eye physiology.  We (re)learned that there are some cues that require 2 eyes, to help us infer depth/distance from the two- dimensional retinal image (e.g., binocular disparity), and some cues that require just 1 (e.g., interposition), some that require motion (motion parallax).

R.G. Bias | | Attention  So, imagine the outrageous amount of sensations!  We employ attention to allow some of these sensations to “make it through” (i.e., come into our conscious consideration) and filter out others. –You aren’t paying attention to your pant leg rubbing against your calf. –OK, NOW you are.  Selective attention – you focus on some sensations and not others.  Divided attention – you try to attend to two or more simultaneous streams of sensations.

R.G. Bias | | So, our “cognitive selves” –Question: Can you remember a 30-digit number? –I say that you can, right now, without practice, seeing it only once, for 1 second, with no time to rehearse.

R.G. Bias | |

R.G. Bias | | So the answer... ... to the question “Can you remember a 30-digit number?” is,  It depends.

R.G. Bias | | If you will...  Help me conduct 3 memory experiments.  This exercise will... –Demonstrate experimental psychological methods –Illustrate models of human memory –Help me get a publication in a journal!!

R.G. Bias | | Experiment 1 Instead of numbers, I’ll present CVC (consonant-vowel-consonant) strings -- like “NEH”. 10 CVCs, one at a time. Presented visually. Don’t have to remember them in order. Pencils down. Ready?

R.G. Bias | | BOV NAZ TOL RIJ DIH REN WUK CAQ GOC MEB

R.G. Bias | | BOV NAZ TOL RIJ DIH REN WUK CAQ GOC MEB

R.G. Bias | | Experiment 2  Now, 10 new CVCs.  Same task -- recall them.  This time, after we read the 10th item, we’ll all count backwards from 100 by 3s, aloud, together.  Then when I say “Go,” write down as many of the 10 CVCs as you can.  Pencils down.  Ready?

R.G. Bias | | VAM LUN XOP REH WIV CIT JEG KUC ZOB YAD

R.G. Bias | | VAM LUN XOP REH WIV CIT JEG KUC ZOB YAD

R.G. Bias | | Experiment 3  Same as Experiment 2.  Yet 10 more CVCs.  Backwards counting.  Don’t have to recall them in order.  Pencils down.  Ready?

R.G. Bias | | GEP TIV WOH LUP MAZ SEX KOL RUC NID BIR

R.G. Bias | | GEP TIV WOH LUP MAZ SEX KOL RUC NID BIR

R.G. Bias | | So here we’ve seen...  The Serial Position Effect (I hope)  STM (and the Recency Effect)  LTM (and the Primacy Effect)  The effect of novelty

R.G. Bias | | Atkinson and Shiffrin Model of Memory (1968)

R.G. Bias | | STM?  Miller’s (1956) “Magical Number 7 +/- 2: Some limits on our capacity for processing information” –Found we could hold only a limited number of items in STM –Realized that we could hold more “items” if we could “chunk” them –So, you might remember just 5 to 7 of these numbers: –But MORE of –And even more of (Bigger chunks!)

R.G. Bias | | Note why we need a short-term memory  Sometimes we need to hold some things in memory – keep them active and accessible -- while we take in NEW information, to make sense of whole, um, thing. –To perform mental arithmetic. –To read a sentence – you need to keep those early words in mind to understand the semantics – the meaning – of the whole sentence. (“The dog that chased the cat bit the boy.”)

R.G. Bias | | Some factors that influence working memory capacity  Meaningfulness of the material (and thus the chunkability)  Pronunciation time – it’s easier to recall Burma Greece Tibet Iceland Malta Laos than it is to recall Switzerland Nicaragua Botswana Venezuela Phillipines Madagascar  Semantic similarity of the items (if I gave you 8 vegetable names you’d do better than if I gave you 8 concrete nouns across various categories)

R.G. Bias | | So... STM or Working Memory  Transient - temporary encoding.  Back-and-forth relationship with LTM: STM can contain information from LTM to work on. Often, information in STM enters LTM.  Direct access to STM contents.  Holds information for current use only; called active memory; primary memory - first stage of memory, as opposed to secondary memory.  Limited capacity: 7 +/- 2. It is a fundamental limitation on our mental capacity.  Rehearsal maintenance - as long as you rehearse items they can be maintained indefinitely. But when attention shifts....  Chunk information to increase capacity - the capacity of STM varies with the meaningfulness of the material. A chunk is a memory unit -- STM capacity is not limited by a physically defined unit but by a meaningfulness unit.

R.G. Bias | | Baddeley’s (2000) model of working memory

R.G. Bias | | Baddeley’s model of working memory (cont’d.)  Phonological loop? –Acoustic confusions. (You know your “inner voice.”)  Visuospatial sketchpad? –You retain both visual and spatial information. –Look at a complex scene, gather visual information, establish landmarks.  Episodic buffer? –Temporary storehouse where we gather and and combine info from two above components. A way to combine info from different modalities (vision and audition)  Central executive –Manages the back-and-forth with LTM –Suppresses irrelevant info – related to attention.

R.G. Bias | | LTM  Comprised of 3 types of knowledge –Semantic (declarative) memory – knowledge about the world; “facts” –Episodic memory – memory for events that happened to you –Procedural memory – how to do things  Large (unlimited?) capacity  Associative, multi-indexed  Duration – perhaps a lifetime –Forgetting; cued recall; recognition vs. recall

R.G. Bias | | Craik and Lockhart (1972)  Argued for a “levels of processing” approach (or “depth of processing”)  Predicts that you will recall of something better if you processed it more deeply –We’re three times more likely to recall a word if we’ve earlier answered questions about it’s meaning than if we’ve answered questions about its physical appearance.

R.G. Bias | | We recall things better...  If we process them more deeply.  If we relate the information to ourselves  If we are asked to recall it in the same context in which we learned it (encoding specificity principle, or context-dependent memory)  If we react positively to the items (the Pollyanna Principle)

R.G. Bias | | So?  So, the answer to “Can you remember a 30- digit number?”, is... It depends. On what? –Whether you hear or see the number. –Whether the number is masked. –Whether you have time to rehearse. –Whether you can “chunk” the numbers. –If there are any intervening tasks. –How meaningful the number is. –WHAT the number is. So, what’s a usable interface? It depends.

R.G. Bias | | Resources  Matlin, M. W. (2009). Cognition. Hoboken, NJ: John Wiley and Sons, Inc. 

R.G. Bias | |  Today’s song was “Remember” by John Lennon.  Why do you suppose we chose to play it before THIS class?