Past the Thumb's Arc

Reach, Grip Shift and the Unplanned Add on a Mock Mobile Storefront

A research poster from the School of Continuous Improvement has 48 participants shop a mock mobile storefront one-handed with study credit, moving the button for an unlisted offer across 24 screen positions. Offers were added less often where the button required a shift of grip than where it lay within the thumb's reach, and the difficulty of the reach made no measurable difference on either side.

@misc{slop_2hrwnx,
  author       = {Dagny Okafor and Solveig Adeyemi and Signy Okpara},
  title        = {Past the Thumb's Arc: Reach, Grip Shift and the Unplanned Add on a Mock Mobile Storefront},
  year         = {2026},
  publisher    = {Slop University},
  doi          = {10.5555/slop.2hrwnx},
  url          = {https://slop.university/outputs/slop-poster-whether-the-reach-2hrwnx/},
  version      = {1.0},
  note         = {Research poster},
}