If you focus on the central spot, the others vanish 

This phenomenon is called 'motion-induced blindness'  losing sight of stimuli that are in plain view. The dots don’t actually vanish your mind just perceives it that way. 
 https://t.co/MoqHhnD3kL https://video.twimg.com/ext_tw_video/1846240244414205952/pu/vid/avc1/726x720/GFliNDKTNwjN3BPr.mp4?tag=12