The researchers have now discovered the actual meaning of too close by examining what's happening when people start feeling in danger by someone else's closeness.

The researchers have now defined invisible boundary that tells the outer limit of our personal space between 20cm and 40cm from one's face. The researchers also discovered the fact that the more of anxious a person is the greater is the size of the personal space.

As the basic etiquette advices of staying out of the personal space of a person the study of the researchers also points at similar things.

A researcher named Dr Gian Domenico Iannetti, stated that the distance appears as a defensive action applied by the brain. He is acting as one of the chief researcher in the study by the department of neuroscience at University College, London, said the distance appeared to be a defensive mechanism employed by the brain.

He stated that the discoveries can be proven helpful for the police and other emergency services personnel in an answer to stress causing situations and in assessments of the dangers.

He further stated that these discoveries will be pointing that the defensive peri-personal space possesses a clean boundary line. He said that the space is also in a relation with the defense. It is the point at which all of us start feeling threatened.