01 — Same task, different world
Changing the screen changes the space available to see and act.
On desktop, gaze covers a large field while the mouse separates the hand from the action point. On a phone, the screen sits in central vision, the finger may occlude content and scrolling rapidly transforms the page. Viewing distance and posture also vary more in natural use.
A saccade measured in pixels is therefore not directly comparable. Even in visual degrees, it remains constrained by visible extent and content density. The device is part of the observed phenomenon.
02 — What persists
The global dynamics remain recognizable.
In the doctoral study, mean fixation duration increased and saccade amplitude decreased on both smartphone and desktop. The K coefficient, which combines these metrics to place exploration between ambient and focal modes, moved toward focal mode. The main transition appeared around the first two seconds.
Task effects on fixation duration were also observed on both devices. This suggests that the timing of visual processing may be more robust than the distance traveled by gaze.
03 — What changes
Geometry and scrolling carry the device signature.
Task effects on saccade amplitude appeared mainly on desktop in this protocol. Stimulus-type effects were broader on smartphone: webpages and images did not use its limited space in the same way.
Kim et al. likewise observed different strategies across search screen sizes, including more scrolling on smaller displays and distinct paths around top results. Responsive design adapts layout to the screen and also changes exploration behavior.
04 — Limits and future
Smartphones increase scale while making control harder.
The thesis study remains exploratory: 21 participants, different groups across devices, a phone fixed on a stand and no detailed touch analysis. These choices improve control but depart from ordinary mobile use.
Valliappan et al. showed that front-camera gaze tracking can reach useful accuracy after personalization and reproduce several classic effects. This democratization can scale research, provided consent, data diversity, calibration and uncertainty remain explicit.
05 — From concept to decision
Responsive design also changes the comparison task.
If a product comparison moves from three columns to one, I would examine which attributes remain visible together and which scroll returns become necessary. The problem may concern what users must remember, as well as button size.
I would compare success and errors on each device, then examine traces and users’ explanations. Findings would guide mobile information hierarchy without assuming gaze coordinates transfer directly.