Data from: Macaque monkeys perceive the flash lag illusion

Transmission of neural signals in the brain takes time due to the slow
biological mechanisms that mediate it. During such delays, the position of
moving objects can change substantially. The brain could use statistical
regularities in the natural world to compensate neural delays and
represent moving stimuli closer to real time. This possibility has been
explored in the context of the flash lag illusion, where a briefly flashed
stimulus in alignment with a moving one appears to lag behind the moving
stimulus. Despite numerous psychophysical studies, the neural mechanisms
underlying the flash lag illusion remain poorly understood, partly because
it has never been studied electrophysiologically in behaving animals.
Macaques are a prime model for such studies, but it is unknown if they
perceive the illusion. By training monkeys to report their percepts
unbiased by reward, we show that they indeed perceive the illusion
qualitatively similar to humans. Importantly, the magnitude of the
illusion is smaller in monkeys than in humans, but it increases linearly
with the speed of the moving stimulus in both species. These results
provide further evidence for the similarity of sensory information
processing in macaques and humans and pave the way for detailed
neurophysiological investigations of the flash lag illusion in behaving
macaques.