 Whereas low spatial frequencies (the 'fuzzier' parts) are attenuated, higher spatial frequencies (an image's fine details) that would otherwise be blurred by the eye movement remain unaffected.This phenomenon, known as "saccadic masking" or "saccadic suppression", is known to begin prior to saccadic eye movements in every primate species studied, implying neurological reasons for the effect rather than simply the image's motion blur.This phenomenon leads to the so-called stopped-clock illusion, or chronostasis.