Effects of Object Height and AOI Margins on Gaze Measures in a Tabletop Task

AOI margin and object height affect gaze assignment; this methodological case study separates them. In a block-imitation task by ten participants, we compared, on the same 4798 fixations, the printed working area (object and support), that area plus a 19 mm margin (separately measured gaze error), and that region raised to object height; the last two differ only in height. Height alone raised the copy area’s dwell share in all ten participants (median +2.4 percentage points), as geometry dictates. For the model’s area, whose region starts on the turntable and can lose gaze, the median was +0.4 points (−5.7 to +32.0), with five rising and five falling. In this layout, the margin moved medians more (copy +7.1, unassigned −14.5). Raised, model and right-tray regions overlapped at every viewpoint; widening them to 40 mm added a median of 0.81 points of assigned time but raised the share qualifying for multiple regions from 0.0% to 13.1%. Two raters judged 200 fixations: the raised region matched their labels more often but also assigned an area where they saw only mat; more assignment is not evidence of accuracy. Size and height are separable choices to report per participant, and their weight depends on layout, tracker and margin.