In the Minority Report movie there are precogs who can predict some events that will occur in the near future. Why do precogs shiver before they make any prediction?
It's precognition (hence pre-cog) also called future sight, and second sight. As they are receiving these "visions of murder", they are experiencing a number of powerful emotions. Bad emotions, which resonate in visual, auditory, physical, and emotional registers. All these things lead their bodies to shiver or shake. It's murder they are experiencing, both victims and murderers emotions. They are scared, in many ways they also feel pain. It's a state they fall into upon seeing or witnessing the crime.
I couldn't explain it better that this author.
The question is posed even more resonantly below the narrative register, in the ways that the film's mood, its images and sounds, play on our sensibilities to amplify a sense of vulnerability, and fear of violent crime. Certainly, the powerful images and sensations evoked by our first viewings of this film remain with us, years later. One of us associates the film with a visual tinge of blue. The other, with the physical sensation of shivering; of a chill that did not leave her even as she walked out of the air conditioned theater in the summer of 2002. The film operated powerfully across the bodies of its viewers, including our own, making skin crawl and shiver, inducing sensations of nausea. One of us found it virtually impossible to sit through the entire film again even when reviewing it in her own living room for this project. Minority Report is as much about feelings of paranoia, anxiety, and fear fullness it induces, as the story of vengeance, retribution, and justice it plays out. Something in the speeds, the color, the jolts, the music, the screaming, incites sensations of panic and need to escape. The film seems to produce in the viewer a certain affect that we might describe as a 'heightened receptivity' to the event no-screen, that is, a sense of being reduce to a twanging tuning fork or vibrating wire. The viewer is placed to occupy the same affective dimension as the 'pre-cogs' - genetically damaged individuals who (are) can see violent crimes before they are actually committed. The visions of the pre-cogs are powerfully affecting. They resonate in the visual, auditory, physical, and emotional registers - the pre-cogs are often seen shaken/shaking during the witnessing, as they experience the emotions of those whose impending death they inhabit. Although it is not immediately evident to the viewer, the opening sequence of this film is one such vision, which has the dual effect of placing the viewer in subject location of the pre-cog and of introducing a sense of anxiety and a desire for escape that seeps into/saturates the entire experience of watching the film. -Studies in Law, Politics and Society - pages 48, 49
(ratchet freak's comment is spot on. It is right in so many ways.)
The pre-cogs are also in water "plugged in" (as stated in the movie) which could be also be the cause of some of the shaking/shivering. They all appear to have scanners or monitors hooked up to their heads reading their brains. From a medical point of view we can only speculate that they are being monitored for health purposes and that the device could be some sort of EEG, reading them for seizure to the brain, epileptic seizure most probably. They could also be experiencing minor seizures at the time of their visions, causing their shivering.