How attention is distributed during visual search: An eye-tracking study

Amersdorfer, Alexandra A., Bryce A. Paradis, and Harold H. Greene

The tops of objects are usually better illuminated by overhead light sources, heads and faces are found towards the top of the body, and all written languages are read from top (where one may find the introduction) to bottom.  As well, the slope of the visual world away from a viewer, regularly places more distant objects towards the upper visual field.  Previous studies have shown that people notice the tops of objects more than the bottoms. Is looking behavior  biased  towards the  (i) top of a search display, and (ii)  upper visual field?  An experiment was conducted to determine how people distribute their attention during a visual search of a context-free display. The target was equally likely to be present in the top and bottom of the display. Participants  wore an eye-tracking device and searched for a small target embedded in a random-dot display. We found significantly more eye fixations, and longer eye dwell times on the upper third of the display than the lower third. Additionally, a significantly higher number of eye movements were directed upwards (into the upper visual field) than downwards.  Experiments of the sort described here contribute to our ability to predict/model human visual exploration.