The robot reacted to its rider's anger by bobbing toward him.

To someone not involved in the situation, it would have looked as though the robot did not react at all.

Then the rightmost robot reacted with its deadly weaponry.

Something about it Derec found affecting, and he suspected other robots might be reacting the same way.

The robot reacted with surprise and urgency that bordered on horror.

Before the robot could react and fight its way out, Pias pressed the button at the side of the hatch.

When the person activates the rod, the robot will react after a short delay.

If it were absent, the robot could not react properly in two dozen obvious ways.

Many researchers have been studying ways to make robots recognize and react to human facial expressions with expressions of their own.

Engineers behind the project say that robots can react more quickly than humans, meaning the number of road accidents could be reduced.