corritore, 7341

ITM 734

Human Factors in Information Systems

Ch. 4 & 5: Attention & Short Term Memory

Fall 2005

Cindy Corritore, Ph.D.

Creighton University

C.L. Corritore2

attention

• examples driving a car -must attend to some

stimuli, ignore others listening to this lecture - attend to slides

and words, ignore other students, physical plant noises

C.L. Corritore3

Broadbent filter theory of attention

• just comes in – filter out 1 msg, this attended one is processed, rest is lost limited capacity to process

• simplistic• contribution

first one to suggest there are a series of processes : theory of information processing system

sensory register > selective filter > STM

C.L. Corritore4

focused auditory attention

• reality: do some processing of unattended messages

• we differentiate between auditory messages using physical characteristics (ie. gender of voice)

C.L. Corritore5

focused visual attention

• flexible

• can focus it

• endogenous vs exogenous process without conscious notice – automatic

shift of attention – more peripheral (exogenous) process when person’s intentions control

(central cues) (endogenous)

• unattended processed but less than attended

C.L. Corritore6

visual attention theories

• spotlight vs. zoom lens both correct in part, likely zoom is more

appropriate (zoom focus in on what’s imp)

• how attention works overall gestalt (salient features), focus

down on objects and components affected by experience (bananas yellow)

C.L. Corritore7

visual search theories

• feature integration get overall gestalt in parallel (objects all

processed together) serial process of object feature analysis

involves focus and experience

• guided search overall gestalt guided by intentions (what

looking for) attention then directed towards objects that

have high importance (activation level)

C.L. Corritore8

divided attention

• doing two things at once

• affected by task similarity – similar how? practice (experience) - automaticity task difficulty – require more resources

than are available?

• what happens: interference

C.L. Corritore9

divided attention theories

• central executive (Kahneman) - limited capacity/resource can do two things at once if don’t exceed resource

• assumptions high arousal increases capacity to a point allocation policy decides on available capacity

enduring disposition (eg. novel, fleeting)intentionsif can finish one task completely if use all resourcelevel of arousal - narrows attentional focus

• so increase effort increases capacity to a point

• perhaps no central executive? – instead many subsystems

• doesn’t explain why …

C.L. Corritore10

divided attention theories

• bottleneck – processing bottleneck do two tasks serially with a short refractory

period between them some support for this although not globally true

• multiple resources – possess pools of resources for multiple stages of processing attention different tasks can be using different resources

(at different stages) potential to multi-task - depends on task

similarity, automaticity, difficulty (drain on resources)

C.L. Corritore11

automaticity

• dramatic improvement with practice• characteristics

prolonged exposure occurs without intention, conscious

awareness/monitoring – always invoked fast does not interfere with other cognitive activities can have processes acting in parallel

• not at conscious level hard to remove or change no processing - just how to react to a stimulus

C.L. Corritore12

automatic processing theories

• controlled processes – require attention, serial processing slower see with varied mapping (ie. not

consistent)

• automatic processes – fast parallel see with consistent mapping

C.L. Corritore13

automatic processing theories

• instance – automaticity is memory retrieval - each time do something, richness of associated memory increases better recall, faster recall until automatic like a past solution is stored that can be

activated• schema’s – organised plans of action

have contention scheduler (selects best automatic response based on context)

have supervisor (makes decisions and troubleshoots, develops new schemas)

C.L. Corritore14

automaticity examples

• Stroop effect (automaticity, divided attention, interference) http://

faculty.washington.edu/chudler/java/ready.html

• OK window for file delete - confirms Delete not the file

C.L. Corritore15

action slips

• activate wrong schema

• Norman discusses 6 types of slips - a result of different kinds of automaticity errors we will talk about these (he has 6 of

these) in Ch. 5

C.L. Corritore16

memory types

• sensory memory

• short-term memory

• long-term memory

C.L. Corritore17

sensory memory/store (multi-store theory)

• buffers for incoming data via senses

• different one for each sense

• types iconic store – visual store; fades rapidly – can

operate on this store echonic store – auditory store -

• short-lived and space-constrained

• persistence (fireworks in vision after the fact)

• some processing even if not attended

C.L. Corritore18

short term memory (multi-store theory)

• selective attention (or else overwhelmed)

• cocktail party phenomenae?

• input from sensory to here via attention

C.L. Corritore19

STM characteristics

• quick access and quick decay (volatile)• limited in size

chunking (experts vs. novices) - phone number402-111-5555

closure - finish something (less errors) - clear out STM

• forgetting time decay? interference with new items? (eg. similarity) attention moves off item?

C.L. Corritore20

STM characteristics

• recency - last few items in list recalled better than middle - holding most recent items in STM negate with interference? visual and auditory channel - no

interference if different channel

• primacy - first few items in list recalled better than middle (more rehearsal)

C.L. Corritore21

STM multistore theory

• STM gateway to sensory and LTM no – eg. conversation direct to LTM

• oversimplified STM is not unitary – nor is LTM

• role of rehearsal exaggerated lots in LTM that is not rehearsed (eg.

snapshot of a birthday celebration)

C.L. Corritore22

STM working memory theory

• all components have limited capacity, temporary storage

• central executive (attentional) controls time-sharing of resources retrieves relevant plans directs selective attention temporary activates LTM as needed likely not unitary

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STM working memory theory

• loops (scratchpads) phonological & articulatory – storage of spoken enters

here, passive store for perception, articulatory process for productionindirect access thru subvocalization (articulatory)for learning new words

visiospatial – storage of spatial and visual info (form, color, movement, spatial data)visual cache (form and color)scribe (spatial and movement; rehearses info from cache)

C.L. Corritore24

levels of processing and retrieval

• retrieval from LTM dependant on processing that occurs at time of learning important:

level or depth of processing – shallow vs. depth perceptual analysis

distinctiveness of the processingamount (elaboration) of processing

deeper levels of processing produce more elaborate, stronger memory traces

differentiate elaborate vs. maintenance rehearsal – elaborate far greater recall success

C.L. Corritore25

a bit about learning

• implicit learning - done without thought language ride a horse

• can’t articulate what you are doing expertise

• characteristics robust (ie fault-tolerant) age & IQ independent low variability between people common to a species different than explicit - may start with explicit, then implicit

strengthens, explicit recedes and get automaticity