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.

大脑中神经信号的传递需要耗费时间，这是因为介导神经信号传递的生物机制速度较慢。在这类神经传递延迟期间，运动物体的位置会发生显著变化。大脑可借助自然界的统计规律性来补偿神经传递延迟，从而以更接近实时的状态表征运动刺激。这一可能性已在闪光滞后错觉（flash lag illusion）的研究框架下得到探讨：当一个短暂闪现的刺激与一个运动刺激对齐时，前者看起来会滞后于后者。尽管已有大量心理物理学研究，但闪光滞后错觉背后的神经机制仍未被充分阐明，部分原因在于此前从未在行为学实验动物中对该错觉开展电生理学研究。猕猴（macaques）是这类研究的理想动物模型，但目前尚不清楚它们是否能感知该错觉。我们通过训练猕猴在不受奖励干扰的情况下报告其知觉体验，证实它们确实能够感知该错觉，且在知觉表现上与人类具有定性相似性。值得注意的是，猕猴感知到的错觉强度弱于人类，但在两个物种中，错觉强度均随运动刺激的速度呈线性增加。本研究结果进一步证实了猕猴与人类在感觉信息加工层面的相似性，并为开展行为学实验猕猴的闪光滞后错觉精细化神经生理学研究铺平了道路。