Shape-Changing Mobile Notifications

Evaluating the Effectiveness of Physical Shape-Change for In-pocket Mobile Device Notifications Panteleimon Dimitriadis and Jason AlexanderLancaster University

Mobile Notifications State-of-the-Art

Sometimes Notifications Fail

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Physical Shape-Change is one Alternative

Hemmert et al: Two-dimensional Tapering Horev, O: Tacto-phoneGomes et al.: MorePhone

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But no in-pocket evaluation

Corner Bending

Corner Bending

Protrusion

Protrusion

Volume Expansion

Volume Expansion

Evaluation 1: Device ConfigurationGoal: understand the influence of device configuration on:(1) Notification efficiency (recognition time, missed notifications)(2) Afforded urgencySetup:16 participants tested all configurationsDevices in front-pocket, white-noise through head-phones

Evaluation 1: Manipulate

Expansion height (all devices)

Pulse type (static, slow, fast) (all devices)

Expansion type (full, tapered)

Number of corners (1,2,3,4)2134

Evaluation 1: ResultsOverall, for all devices:(1) Identification time decreased with larger protrusions and faster pulsing movements.

(2) Perceived urgency increased with larger shape-change movements and with increasing pulse rate.Missed Notifications:

1%

0%

9%

Evaluation 2Physical shape-change is most useful in noisy/busy environments

Simulated environment with walking and white-noise.

Compared the optimal configurations of each device with traditional vibrotactile feedback.

10 participants, 20 notifications

Evaluation 2Results:25/200 notifications missed, 21 from vibrotactile.

Shape-changing notifications recognised faster.

SummaryShape-change can provide more reliable alerts than traditional vibro-tactile notifications.

Perceived notification urgency can be changed by configuring the parameters of shape-change.Panteleimon Dimitriadis and Jason AlexanderLancaster Universityj.alexander@lancaster.ac.uk

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