manipulating attention in computer games matthias bernhard, le zhang, michael wimmer institute of...

Manipulating Attention in Computer Games

Matthias Bernhard, Le Zhang,

Michael Wimmer

Institute of Computer Graphics and Algorithms

Vienna University of Technology

Attention without a Task

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Attention

Stimulus

But during Game Play...

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Attention

Stimulus

Attention only to Task

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Attention

Stimulus

task-relevant

Inattentional Blindness

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Attention

Stimulus

not attended

Manipulating Attention

Why ? Control difficulty of a game

Decrease or increaseAvoid Inattentional Blindness

Notify user about unexpected, but important information

Visibility of advertisements How ?

Influence preattentive vision Increase saliency

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Increasing Saliency

Bottom-up / Stimulus driven :Contrast, warm colors, high

luminance,... Changes: motion, flicker, ... Previous work !

Top-down biased:During visual search tasks This work !

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This Work

Simple but effective guiding principle Manipulate attention during a task Preliminary evaluation with a user study

Action computer gameDirect attention towards an advertisement

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Increasing Bottom-Up Saliency

Intelligent lighting [El-Nasr 2005]Techniques used in theatres and movies

h

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El-Nasr, M.S., Intelligent Lighting for Game Environments, Journal of Game Design, 2, 1 (2005)

Increasing Bottom-Up Saliency

Subtle Gaze Direction [Bailey et al. 2008]Subtle modulation in

peripheral FOVStop modulation

before fixationEye-tracker required

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Bailey,R,McNamara,A.,Sudarsanam,N.,Grimm,C., Subtle Gaze Direction, ACM Transactions on Graphics,, 28, 4 (2008)

Modulation

Problem: Inattentional Blindness

Bottom-up saliency not necessarily sufficient Strong focus on task, particularly in games

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Increasing Top-Down Biased Saliency

Guided Search [Wolfe 1994]Top-down influence during visual searchBias towards features of a search targetMany search tasks in games

Our proposal:Generate distractors of g. search itentionally Adjust design of search targets

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Advertisements Unattended

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Attention

health item

Change a Search Target

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Attention

Advertisement Becomes Distractor

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same featuresAttention

Advertisement Becomes Distractor

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similar color

same featuresAttention

User Study with Computer Game

2D action game with 3D background

6 advertisements in background1 distractor adv. + 5 other adv.BichromaticReal brands Realistic lighting

(raytraced scene)

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Game elements

Background scene

Procedure

Play game (3 minutes) Distraction (6 minutes) Memory Test

Recognition test3 alternatives/forced choice1 in-game advertisement

+ 2 not in game adv.Select with mouseclick36 trials: 6 per advert.

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Game

Memory test application

Test Group (12 Participants)

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expectedattention

distractor

target

Control Group 1 (N=12)

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expectedattention

target

Control Group 2 (N=12)

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expectedattention

target

replaced

Results: Distractor Advertisement

Around chance level in control groups

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Test

Control 1

Control 2

pro

po

rtio

n

corr

ect

an

swe

rs

Results: Distractor Advertisement

Around chance level in control groups Difference betw. test and controls: p<0.001 (Wilcox)

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Test

Control 1

Control 2

pro

po

rtio

n

corr

ect

an

swe

rs

***

Results: Other Advertisements

Also higher scores in test group

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Test

Control 1

Control 2

pro

po

rtio

n

corr

ect

an

swe

rs

Results: Other Advertisements

Also higher scores in test group One possible reason: similarity of color

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Test

Control 1

Control 2

pro

po

rtio

n

corr

ect

an

swe

rs

similar color

Results: Other Advertisements

Interesting: difference betw. Test & Control 2 Generally increased attention to background ?

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Test

Control 1

Control 2

pro

po

rtio

n

corr

ect

an

swe

rs

p=.12

p=.14

Conclusion Control group:

Advertisements not remembered well (also salient ones!!!)

Inattentional Blindness did occur Bottom-up saliency necessary, but not sufficient

Test group:We „broke through“ Inattentional BlindnessProbably increased attention to other

background elements too

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Future work

More studiesMultivariate analysisSubtle feature combinationsDynamic viewpointEye-tracking

Visualization tool for game designers Encode current task in visual search tasksComputational simulation of Guided Search Related work: Navalpakkam and Itti, „Modelling the

Influence of Task on Visual Attention“, Vis.Research, 2005

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Thanks for your attention !

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Variation across Participants

Distribution visualized with box plots

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pro

po

rtio

n

corr

ect

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swe

rs

Increasing Bottom-Up Saliency

Use pop-out features Shrill colors, brightness, etc

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© Ghostbusters: The Video Game