question:  Why are the grey helmets necessary?
context: "He's gone completely hay-wire. Nobody's been able to get near him for three weeks, and now at six o'clock this morning he decides he's leaving the Farm. "So you bring him down here," said Lessing sourly. Lessing nodded at Dorffman and stepped into an adjoining room with him. "Full psi precautions?" asked Dorffman. The first was from Roberts Bros., announcing another shift of deadline on the book, and demanding the galley proofs two weeks earlier than scheduled. As director of psionic research at the Hoffman Medical Center, he had long since learned how administrative detail could suck up daytime hours. It bore the letterhead of the International Psionics Conference: Dear Dr. Lessing: When they were finally forced to recognize that this great and powerful force did indeed exist in human minds, with unimaginable potential if it could only be unlocked, they had plunged eagerly into the search, and found themselves in a maddening bramble bush of contradictions and chaos. Natural laws came crashing down about their ears as they stood sadly by and watched things happen which natural law said could never happen. And the more they struggled, the thicker and more impenetrable the bramble bush became— But now David Lessing had discovered a pathway through that jungle, a theory to work by— At his elbow the intercom buzzed. "Within the stronghold of psionic research at last. "I think you'd better wait before you do that," Melrose said sharply, "because I'm planning to take you apart at the Conference next month unless I like everything I see and hear down here today. But mostly, I want to see just what in psionic hell you're so busy making yourself an Authority about." "If the papers you've already published are a preview, we think it's false as Satan." "So far, we haven't found any way to set up logical controls," said Melrose. "We haven't been energetic enough to find an orthodox approach that got us anywhere.
output:  The helmets block external psionic forces.
options:  The helmets block external psionic forces.  The helmets improve the reception of external psionic forces.  The helmets are for safety, as the children are heavily medicated and at high risk for falling.  The helmets amplify the childrens' psychic abilities.