Now, a pen to bust stress

Doctoral student Miguel Bruns Alonso from the Delft University of Technology in the Netherlands found that people tend to play with their pens when they are tense.

"That is why I have developed a pen which can detect 'nervous' movements and determine whether the user is stressed," he said, according to a Delft statement.

"When it detects the quicker movements associated with stress, the pen gradually becomes more difficult to move around. This encourages users to move in a more relaxed way, which in turn makes the pen yield more easily again," Alonso said.

"Sensors in a pen could provide an unobtrusive way of measuring stress levels. Giving users the right feedback could then help them deal with their stress in a constructive way," he added.

When the pen was evaluated in an experiment, people who received feedback on their behaviour had a lower heart rate (around five percent lower) than those who received no feedback. They experienced less psychological stress.