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Human beings have the ability to communicate with their minds. This form of telepathy is quick and efficient, relying on concepts and ideas rather than words. A person can mindlink with others in their immediate vicinity, say20-30 feet. Rarer, stronger individuals are able to extend this to an indeterminate amount. Individuals can share thoughts, feelings, and memories with no misunderstandings confusion between them, and can include multiple people at a time. This ability has been present in humanity since its earliest days.
All people have a "shield" surrounding their minds, protecting them from unwanted intrusion. Individuals generally cannot force a mindlink with someone. They have to "ping" the person mentally by sending out a signal. That person chooses to respond and opens a connection, or disregards it. All people are capable of this for of communication, but telepathy isn't used very often in society. People normally use traditional forms, such as body language and talking, with most other people.
What would be a good reason for why this ability isn't widely used despite it being more efficency and reliable?
EDIT I have increased the distance of 3-5 feet to 20-30 feet on advice from respondents.