Time-dependent modulation of saliency-driven visual attention in free viewing

Area of Science:

• Visual perception research
• Cognitive neuroscience
• Human-computer interaction

Background:

• Understanding visual attention is crucial for fields like psychology and AI.
• Gaze behavior reveals how individuals process complex visual information.
• Distinguishing bottom-up (stimulus-driven) and top-down (goal-driven) attention is key.

Purpose of the Study:

• To investigate gaze behavior similarities across observers in natural scenes.
• To determine if visual saliency guides attention during free viewing.
• To clarify the roles of bottom-up and top-down influences on visual attention.

Main Methods:

• Eye-tracking was used to record gaze behavior in 45 adults viewing 10 natural scenes.
• Fixation heatmaps and gaze parameters were computed.
• Jensen-Shannon Divergence (JSD) measured heatmap similarity over time, compared against saliency maps.

Main Results:

• Initially (first 7.5s), 72% of fixations were directed towards salient regions, with high inter-observer similarity (JSD: 0.15).
• Over 15s, fixation overlap with salient regions varied (52-84%), influenced by scene crowding and social content.
• Gaze similarity decreased over time, indicating a shift towards individualized viewing patterns.

Conclusions:

• Free viewing starts with consistent, saliency-driven attention but becomes more personalized as top-down influences grow.
• Scene characteristics modulate the temporal dynamics of attention.
• This research has clinical implications for assessing visual and cognitive impairments.