Eye
and Head Movements in the Acquisition of Visual Information
J. A. Stern, T. B. Brown, L. Wang, & M. B. Russo |
Much
of the literature dealing with the measurement of eye movements is
restricted to data collected under conditions where the head is "stabilized".
Since in the "real world" such restrictions cannot readily
be imposed on operators, we here review the Literature dealing with
the use of head movements in the acquisition and processing of visually
presented information. Task difficulty is associated with an increase
in the likelihood of using head movements to acquire visually presented
information. Such head movements have been described with visual
information subtending as little as 5-10 degrees of arc. The present study, requiring subjects to identify and process information presented at 10 degree eccentricity, determined that such head movements do occur. Head movements were not measured directly but inferred from differences in eye movement amplitude as measured with electrooculography, and gaze shift measured with video camera technology. We raise the issue of generalizability of results obtained under conditions where the head is "stabilized" to conditions where it is free to move. Key words: gaze, eye movement, EOG, head movement, saccade |