Fig 2. State spaces used to define sequential scan patterns during scene viewing.

Scan patterns during scene viewing were defined by mapping fixation positions to 3 different state spaces. The Radiating state space (a) measured viewer tendencies to shift their overt attention between central and peripheral scene information. The Vertical and Horizontal state spaces (b and c) measured observers tendencies to shift their overt attention vertically and horizontally. Each of the state spaces contained an outside state 5 that reflected the center bias observed in the global fixation density (d) across all scenes and participants. Each state space was applied globally across all 40 scenes.