Cognition and Perception: A Short Review

To add: non-tech error stuff

Attention blindness demos Speech errors and disfluency Emotion and design (3 teapots) Just noticeable differences (JNDs) Add Strayer cell phone study

Relevant topics

Perception Motor abilities Attention Reading Sensory memory Working memory

Long-term memory Reasoning Decision-making Speech perception

and production Discourse

Perception

Vision Rods and cones Visual acuity Color: hue, intensity, saturation Distance estimated by size (+intensity) Gestalt principles

Gestalt theory says perception is:

Emergent Constructive Multistable Invariant

Subjective contour

can “create" a figure.

What do you see?

Some Gestalt Principles

Proximity

Similarity

Good continuation

Closure

Gestalt Principles

Proximity

Gestalt Principles

Similarity

Gestalt Principles

Good continuation

Gestalt Principles

Closure

Gestalt Principles

Closure

What do you see?

Figure-ground segregation (stable)

Figure more thing-like, more memorable, smaller seen as being in front of the ground

Ground seen as unformed material extends behind the figure

Figure-ground segregation (stable)

Smaller areas seen as figures

Figure-ground segregation (stable)

Vertical/ horizontal orientations seen as figures

Perception

Vision

Hearing Pitch, loudness, and timbre Pitch range: 20 Hertz - 15,000 Hertz Resolution Speech vs. other sounds

Perception

Vision

Hearing

Touch Mechanoreceptors, thermoreceptors,

nociceptors (pain) Different resolution at different points Feedback is important

Perception

Vision

Hearing

Touch

Smell

Taste

Modalities; speed/accuracy; practice effects

Reaction times differ by modality Integrating 2 modalities into 1 percept Speed trades off with accuracy Skill increases with practice

(Power Law of Practice)

Attention

Pop-out and serial vs. parallel search

Attention

Pop-out and serial vs. parallel search

0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 V 0 0 0

0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0

Attention

Pop-out and serial vs. parallel search

0 0 0 0 0 0 0 0 0 0 | | | | | | | | | |

0 0 0 0 0 0 0 0 0 0 | | | | | | | | | |

0 0 0 0 0 0 V 0 0 0 | | | | | | | | | |

0 0 0 0 0 0 0 0 0 0 | | / | | | | | | |

0 0 0 0 0 0 0 0 0 0 | | | | | | | | | |

Attention

Pop-out and serial vs. parallel search

O N N N O O O N N O N O

O O O N O O O N N O N N

N O O N O O N O O N N O

O N O N O N O O O N O N

N O O N O O O N N O O N

Attention

Pop-out and serial vs. parallel search Highlighting Motion, flicker Sounds

Change blindness

Some fun demos:http://viscog.beckman.uiuc.edu/djs_lab/demos.html

What’s changing?

What’s changing?

What makes seeing the change so hard?

Change blindness

Inability to detect what should be obvious changes in a scene

| 400 ms | 40-80 ms | 400 ms |

Original Image Blank Modified Image

Mud Splashes

No Mud Splashes

Change blindness

Inability to detect what should be obvious changes in a scene. This is affected by Interrupting with a blank screen Distraction such as the “mud” (captures attention)

| 400 ms | 40-80 ms | 400 ms |

Original Image Blank/Mud Modified Image

Flicker

No Flicker

More examples:

http://www.usd.edu/psyc301/Rensink.htm

Conversations and cell phones

Auto accidents increase during cell phone use

Yet people safely talk to their passengers all the time

So it follows that the problem must be due to dialing, handling the phone, etc.

Or does it?

Strayer & Johnston’s expts (in press)

Visual tracking task with joystick Conditions: hands free or handheld

Converse with someone in another room Listen to the radio or books on tapeShadowingPrompted word generation task

Results:

Performance was worse for subjects on cell phones than for subjects listening to radio, books on tape, or shadowing. Twice as many red lights were missed, and RTs increased!!

Whether the phone was hand-held didn’t matter at all!

What do you think causes the poor performance of people on cell phones?

Inattention Blindness (IB)

When observers fail to notice an unexpected object or event

Occurs when attentional resources are directed toward another task

Attention Influences Perception

Inattentional Blindness: involves missing a (remarkable!) change because you’re not expecting it and not attending to it.

Example: Man/office/phone moviehttp://viscog.beckman.uiuc.edu/grafs/demos/23.html

Notice anything strange?

Simons & Chabris (1999)

Attention Influences Perception

Inattentional Blindness: involves missing a (remarkable!) change because you’re not expecting it and not attending to it.

Example: http://viscog.beckman.uiuc.edu/grafs/demos/15.html

Count passes made by the white team or the black team (easy task)

Count bounce passes and also count aerial passes (hard task)

Simons & Chabris (1999)

Attention Influences Perception Inattentional Blindness: involves missing a

(remarkable!) change because you’re not expecting it and not attending to it.

Example: More people see gorilla

with easy task More people see gorilla

when attending to black team (83%) than white team (42%)

Similarity matters!

Simons & Chabris (1999)

Inattentional Blindness - another ex.

Pilots landing an aircraft simulator Experimenters were interested in a new

heads-up display Pilots didn’t notice a large plane placed

on the runway at the last minute

Haines (1991)

Stages of cognitive processing

(Reed, p. 3, Figure 1.1)

Sensory memory

Iconic memory - fleeting, hi-res buffer

Must be attended to to be remembered Echoic memory Haptic memory

(Characteristics vary with context)

Working memory

Rapidly accessed, rapidly decays Capacity limitation: “7±2” (Miller) Baddeley’s 3 part model

Visuospatial sketchpadPhonological loopCentral executive

Interference

Long Term Memory

Unlimited capacity, slower to access Interference and forgetting Encoding specificity,

transfer-appropriate processing Levels of processing theory

retrieval depends on encoding!

graph. < rhyme < semantic < personal

Visual imagery, dual coding theory

Long Term Memory (cont.)

Semantic organization Tip-of-the-tongue effect (interference) Schemas Distortions in memory

Reasoning

Wason’s 4-card task

Reasoning

Wason’s 4-card task

Decision making

Framing effects

Program A: save 200 peopleProgram B: 1/3 probability of saving all 600

2/3 probability of saving no one

Decision making

Framing effects

Program A: save 200 peopleProgram B: 1/3 probability of saving all 600

2/3 probability of saving no one

72% choose A; 28% choose B!!

Decision making

Framing effects

Lose a $50 ticket Lose a $50 bill

Would you buy another ticket?

Decision making

Framing effects

Lose a $50 ticket 46% YES, 54% NO Lose a $50 bill 88% YES, 12% NO

Would you buy another ticket?

Decision making

Framing effects Anchoring effects

Do you think Dr. Brennan is older or younger than 20/60?

Please give your best estimate of her age.

Decision making

Framing effects Anchoring effects

Do you think Dr. Brennan is older or younger than 20/60?

Please give your best estimate of her age.

Anchored at 20: 37.7 years old

Anchored at 60: 39.3 years old (p < .05)

Conclusion:

Review your knowledge of cognitive and perceptual psychology!

You can distill principles of human-computer interaction and explain people’s performance and errors from what you know about human cognition and perception!