Psych 435 Attention

Issues Capacity –We can’t respond to everything in the environment –Too many pieces of information –we can only actively respond to a subset of these Attention –The selection of relevant cues to respond to –Cues may be externally or internally generated

Attention What is attention? –“The concentration of mental effort on sensory or mental events” Phenomena –Switching vs. sharing attention –Attention Capture –Visual Search –Selective attention- Stroop

Examples of Controlled vs. Automatic Processes Show 3 pairs of search demos Each member of each pair will have a few or a lot of items Search for a single target

Find the T: T L L L L L L L

This was an automatic process: fast

Find the T: T L L L L L L L L L L L L L L L L L L L L L L L L L L L L L L L L L

This was an automatic process: still fast even with more distractors

Find the T: T L L L L L L

Slower without color

Find the T: T L L L L L L L L L L L L L L L L L L L L L L L L L L L L L L L L L

This was a controlled search- slower, look at each letter Much slower than with colored T

Find the Red L L L L L L T T T T T

Slow: searching for a conjunction

Find the Red L T L L L L L L L L L L L L L L L L L L L L L L L L L L L L L L L L L T T T T T T T T T T T T T T T T T T T T L

Even slower- searching for a conjunction

Data from Display Set-Size Experiment Fast search done with automatic (preattentive) mechanisms Done in parallel Slow search done with controlled (attentive) mechanisms Done in serial

Applications of Attentional Seach List search situations and decide if fall into preattentive or attentive search requiring focal attention E.g. –Search computer screen for icon –scan crowd for people –scan crowd for americans –look for airplane in sky What makes things preattentive? –probably the amount of difference between the objects –L’s and T’s are similar –Red and blue are quite different –Looking for small differences requires focal attention

Models of attention Filter Models –Recognition after Filtering »Broadbent -or- –Recognition before Filtering »Broadbent’s critics Attentuation Models –Treisman Automatic vs. Controlled Processes –Also called Preattentive vs. Attentive Processes. –Neisser –Schneider and Shiffrin

Filter Models What is a Filter? A description of the response properties of the system Describes what a system responds to, and what it doesn’t respond to.

Types of Filter Models DetectionRecognition Input Detection Input Filter Recognition Detection Input Filter Recognition Recognition Before Filtering: Recognition After Filtering (Broadbent):

Broadbent’s Filter Model Channels carry different types of information E.g. color, spatial frequency, pitch, hot, etc. Apply mental effort: selectively process info coming from a small set of channels We must do this: limited capacity processing and memory system –We just can’t deal with all the information at once However, can switch between channels

Broadbent’s Filter Model cont. On the basis of some aspect of the stimulus or our memories, we can switch between channels This switching may be voluntary or involuntary Switching takes effort, reduces performance –Broadbent’s dichotic listening techinque- present two digits at once, one to each ear –8, 3, 2 in left ear –9, 1, 5 in right ear –recall by ear (left or right): subjects respond “ ” – or in order: subjects respond “ ” –performance for latter task is reduced (65% to 20%) –In second task subjects had to switch more often- hurts.

Broadbent’s Filter Model cont. Problems: Gray and Wedderburn (1960) –Easy to switch if information in the to-be-switched-to ear is relevant –e.g.: Story continues in alternating ears Problems: GSR experiments –Associate word with shock- hearing word elicits a GSR response. –When that word is presented in unattended channel, produces GSR response. –Semantically similar words also elicit response- some semantic processing takes place in unattended channel.

Attenuation Models-Treisman Info in unattended channels is still processed –but at a reduced rate –info in unattended channels is attenuated.

Treisman’s Attention Model

Attention Capture

Failures of Selective Attention Attention is supposed to focus in on what you want to attend to Exclude irrelevant information

Stroop Task Blue Green Yellow Red Yellow Green Blue Red Green Blue Red Green Yellow Blue Green

Stroop Task *****

Stroop Task Blue Green Yellow Red Yellow Green Blue Red Green Blue Red Green Yellow Blue Green

Stroop Task Yellow Blue Red Blue Green Blue Red Yellow Blue Red Yellow Blue Green Red Blue Yellow

Stroop Failure of selective attention Race model –Word name is processed automatically –Color is not so automatic –Both arrive at the same time, we have a hard time attending to the relevant stimulus attribute –Doesn’t happen upside down

Stroop Task

Failure of Attention: Failure to Disengage Mind Develops Brain clip –infant- failure to disengage

Spatial Attention: Posner Task A Attention switches to here (but eyes don’t move) Target might appear here: A or here: TimeTime Fixation Point Cue 75% accurate

Sharing Attention: Dual Tasks Do two things at once: can they be performed at the same time? Do they interfere? Experiment has 3 conditions Task A alone Task B alone Task A and B together at the same time

Sharing Attention: Dual Tasks Example: Pat head and rub belly Now speed up just your belly If you can’t do it, it suggest that they share the same processing capacity Same brain area?

Sharing Attention: Dual Tasks words per minute Example: Task A: Driving without an accident Task B: Talking on cell phone Can you talk on your cell phone at the normal rate while still driving without getting into an accident? Normal Save Driving Speed: 30 mph Normal speaking rate: 80 wpm Safe Driving Speed a b c 40

Central Executive Interactions

Pet Evidence-Right Parietal

Lesion Data- Attending to Different Spatial Scales