Nonblurred regions show priority for gaze direction over spatial blur.

Area of Science:

• Visual perception
• Oculomotor behavior
• Image processing

Background:

• The human eye forms images with a dynamic depth of focus, resulting in retinal images with both focused and blurred objects.
• Understanding how the visual system processes scenes with varying depths of focus is crucial for comprehending eye movement patterns.

Purpose of the Study:

• To investigate the effect of a mixed visual diet, containing both focused and blurred image regions, on human eye movement patterns.
• To determine if observers preferentially fixate on clearer image areas within a composite visual scene.

Main Methods:

• Composite stimuli were created, featuring an intact photograph alongside progressively blurred versions in a 3x3 array.
• Eye movements were recorded for these stimuli and their root mean square (RMS) contrast-equated versions.
• Fixation patterns were analyzed to identify preferences for regions with varying degrees of spatial blur.

Main Results:

• Observers significantly fixated more on stimulus regions with little or no blur (p < .001).
• This fixation pattern persisted even in RMS contrast-equated stimuli, suggesting it's not solely due to contrast variations.
• Regions with less blur were fixated earlier, while more blurred regions were fixated later or not at all during presentations.

Conclusions:

• Spatial blur is a significant factor influencing eye movement patterns during scene perception.
• The human visual system demonstrates a clear preference for fixating on sharp, in-focus image areas.
• These findings contribute to understanding how visual scene complexity, specifically depth of focus, guides attention and gaze behavior.