Perceived speed in peripheral vision can go up or down

Area of Science:

• Visual perception
• Neuroscience
• Ophthalmology

Background:

• The perception of visual stimuli, including speed and contrast, differs between central (foveal) and peripheral vision.
• Luminance levels significantly impact visual processing, affecting different retinal cell pathways (magno- and parvocellular).

Purpose of the Study:

• To investigate how perceived speed and contrast of visual patterns change in peripheral vision compared to foveal vision.
• To determine the influence of eccentricity, pattern speed, and luminance on perceived visual speed.

Main Methods:

• Measurements of perceived speed and contrast were taken for various patterns at different eccentricities.
• Experiments were conducted under both mesopic (low light) and photopic (high light) luminance conditions.
• Perceived contrast was equated across conditions to isolate the effect on speed perception.

Main Results:

• Perceived speed is dependent on eccentricity, pattern speed, and luminance.
• At photopic levels, peripheral patterns appear slower; at mesopic levels, fast patterns can appear faster peripherally.
• When contrast is matched, perceived speed decreases with eccentricity, independent of pattern speed.

Conclusions:

• Peripheral speed encoding aligns with a ratio-type speed code modulated by ganglion cell density.
• Luminance is a critical factor influencing whether peripheral stimuli are perceived as faster or slower than foveal stimuli.