Having a flexible smartphone or tablet sounds like a cool idea… But ever wondered how our day to day interaction with these devices may change when we suddenly make them deformable? Well that’s the question I tried to answer in this project; more specifically, how we can use our thumb for touch interactions on flexible tablet. Following was my process:


Initially, I investigated the existing interaction techniques in the similar domain in order to refine the research question and determine down the scope of the project. At this stage, I decided on testing how we can use our thumb (of the hand holding the tablet) for touch input on flexible tablets. This was based on the fact that when we hold a tablet, typically our thumb rests on the front while the other fingers provide support from the back, making that portion of the device rigid enough to avoid erroneous interactions.

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I, along with the some other members at CIL Lab, brainstormed on possible touch interactions that we can perform with the thumb of the hand holding the tablet.

Usability Session Tasks

I decided on some simple tasks such as changing shapes with tapping.

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Factors and Metrics

Determine quantitative and qualitative metrics, questionnaires etc. For instance, one of the factors was hold position. I tested three hold positions based on the literature review.

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Paper Prototypes and Pilot Studies

I conducted few iterations of paper prototypes and pilot studies in order to fine-tune the usability study design. For instance, after few pilot studies, I had a clearer idea about how many ‘tapping regions’ per hold position I should test.

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A high fidelity prototype was developed for the usability sessions

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Usability session

I recruited 20+ participants for usability testing. Each session lasted about an hour which consisted of performing several tasks using the prototype and answering post-test questionnaires. The post-test questionnaires included several open-ended and semi-structured questions

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Data Analysis

I analyzed the performance data collected automatically while users interacted with the prototype, the Likert scale data from the post-test interviews, and the open ended answers.

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Interaction Technique Guidelines

I develop interaction technique guidelines based on the findings in usability session data. For instance, based on the study, one recommendation was to avoid diagonal swipe as it was causing user fatigue and also produced many false positives during the study.