In the far distance a helicopter skimmed down between the roofs, hovered for an instant like a bluebottle, and darted away again with a curving flight. It was the police patrol, snooping into people's windows. (1.1.4)
Oceanians are used to living in a constant state of surveillance - either through technology or police patrol.
Inside the flat a fruity voice was reading out a list of figures which had something to do with the production of pig-iron. The voice came from an oblong metal plaque like a dulled mirror which formed part of the surface of the right-hand wall. Winston turned a switch and the voice sank somewhat, though the words were still distinguishable. The instrument (the telescreen, it was called) could be dimmed, but there was no way of shutting it off completely. (1.1.3)
Oceanians live in a constant state of being monitored by the Party, through the use of advanced, invasive technology.
Winston kept his back turned to the telescreen. It was safer, though, as he well knew, even a back can be revealing. (1.1.6)
Fear runs so deep in Winston that he fancies that by turning his back on a telescreen, his rebellious spirit may be sniffed out.
It was terribly dangerous to let your thoughts wander when you were in any public place or within range of a telescreen. The smallest thing could give you away. A nervous tic, an unconscious look of anxiety, a habit of muttering to yourself - anything that carried with it the suggestion of abnormality, of having something to hide. In any case, to wear an improper expression on your face (to look incredulous when a victory was announced, for example) was itself a punishable offense. There was even a word for it in Newspeak: facecrime, it was called. (1.5.65)
The Party's surveillance tactics and technology are so advanced that even the smallest twitch can betray a rebellious spirit.
"That's a first-rate training they give them in the Spies nowadays - better than in my day, even. What d'you think's the latest thing they've served them out with? Ear trumpets for listening through keyholes! My little girl brought one home the other night - tried it out on our sitting-room door, and reckoned she could hear twice as much as with her ear to the hole." (1.5.67, Parsons)
Its reach not limited to technology, the Party employs children against their parents as another way of to survey behavior.
He took his scribbling pad on his knee and pushed back his chair so as to get as far away from the telescreen as possible. To keep your face expressionless was not difficult, and even your breathing could be controlled, with an effort: but you could not control the beating of your heart, and the telescreen was quite delicate enough to pick it up. (1.7.22)
The Party's chief monitoring device, the telescreen, is so sensitive that it can detect the rapid beatings of a person's rebellious heart.
In general you could not assume that you were much safer in the country than in London. There were no telescreens, of course, but there was always the danger of concealed microphones by which your voice might be picked up and recognized; besides, it was not easy to make a journey by yourself without attracting attention. (2.2.2)
Its reach not limited to telescreens, the Party also places hidden microphones throughout London to monitor the interactions of its constituents.
In Oceania at the present day, Science, in the old sense, has almost ceased to exist. In Newspeak there is no word for 'Science'. The empirical method of thought, on which all the scientific achievements of the past were founded, is opposed to the most fundamental principles of Ingsoc. And even technological progress only happens when its products can in some way be used for the diminution of human liberty. (2.9.30).
The Party employs science and technology to curtail human freedom and privacy, and to control human behavior.
"It was behind the picture," said the voice. "Remain exactly where you are. Make no movement until you are ordered."
It was starting, it was starting at last! They could do nothing except stand gazing into one another's eyes [...] unthinkable to disobey the iron voice from the wall. There was a snap as though a catch had been turned back, and a crash of breaking glass. The picture had fallen to the floor uncovering the telescreen behind it. (2.10.21-24)
Winston and Julia come to a rude awakening when it turns out that their rented room has a hidden telescreen that has surveyed them for their entire affair.
"Down with Big Brother! Yes, I said that! Said it over and over again, it seems. Between you and me, old man, I'm glad they got me before it went any further [...]."
"Who denounced you?" said Winston.
"It was my little daughter," said Parsons with a sort of doleful pride. "She listened at the keyhole. Heard what I was saying, and nipped off to the patrols the very next day. Pretty smart for a nipper of seven, eh? I don't bear her any grudge for it. In fact I'm proud of her. It shows I brought her up in the right spirit, anyway." (3.1.48-50)
With children, the success of the Party's plan manifests further in that the children serve as extra surveillance forces for the Party. Indeed, the child of Party member Parsons is so overcome with love for and indoctrination by the Party that she surveys and turns in her own father in for thoughtcrime.