After repeated bombardment by drugs, the system loses sensitivity to more natural rewards.

"If the same scent is in the same environment all the time, you start to lose sensitivity to that scent," she says.

Allow the resident to decide the water temperature, but be aware that people lose sensitivity to heat with age.

This analog machine loses sensitivity over time and requires periodic recalibration to remain accurate.

They are also subject to gradual failure due to using up the reactive materials, and may lose sensitivity in cold conditions.

They also become lose sensitivity as storage time increases.

And for people who have lost sensitivity in their hands, the faucet could avert a burn.

Some people lack one colour pigment, and so lose sensitivity to part of the spectrum, usually red or green.

"They're losing sensitivity to this" as they grow older, Ms. Weikum said.