Final answer:
Radiant heaters, such as infrared lamps, preferentially warm objects and surfaces rather than the air through the emission of infrared radiation, which is a method of heat transfer that can operate without a medium.
Step-by-step explanation:
Radiant heaters, such as infrared lamps or quartz heaters, work by emitting infrared radiation, which does not primarily heat the air but rather directly warms the objects and surfaces it comes into contact with. This is because radiation is a method of heat transfer that does not require a medium; it can transfer energy through the vacuum of space as it does from the Sun to the Earth. Infrared radiation is absorbed more readily by solid objects, including humans, than it is by the air. This is in contrast to convection-based heating systems, like gravity furnaces, which heat air directly to create a convective loop for distributing warm air throughout a space.