The lawful perception of apparent motion

Area of Science:

• Visual perception
• Motion perception
• Psychophysics

Background:

• Apparent motion perception involves successive stimulation of separate locations.
• The interaction between spatial and temporal distances in apparent motion perception is debated, with conflicting reports of space-time coupling versus tradeoff.
• Korte's third law describes space-time coupling in motion perception.

Purpose of the Study:

• To resolve the controversy regarding space-time coupling and tradeoff in apparent motion perception.
• To investigate the influence of speed on the relationship between spatial and temporal distances in apparent motion.
• To develop a unified understanding of space-time interactions in motion perception.

Main Methods:

• Utilized a normative theory of motion measurement and human spatiotemporal sensitivity data.
• Conducted two experiments using suprathreshold multistable apparent-motion displays (motion lattices).
• Reconstructed suprathreshold equivalence contours analogous to isosensitivity contours.

Main Results:

• Demonstrated a speed-dependent transition between space-time tradeoff and coupling.
• Observed tradeoff at low speeds and coupling at high speeds.
• Provided empirical evidence supporting the coexistence of both phenomena under different speed conditions.

Conclusions:

• The apparent motion perception system exhibits both space-time tradeoff and coupling, depending on the speed of motion.
• This finding reconciles conflicting previous research by highlighting the role of speed in modulating space-time interactions.
• The reconstructed equivalence contours offer a novel way to characterize suprathreshold apparent motion perception.