Many animals, including humans, look at each other to signal interest or threat. Numerous studies have documented the biological importance of eye gaze and shown that the brain is hardwired to recognize it and process it fast. Eyes meeting can lead to moments of raw emotions and autonomic physiological responses. But any deviation of what is considered normal can signal a problem: Short eye contact may lead people to perceive someone as less confident and untrustworthy. Avoiding it altogether has been suggested to be a symptom of autism spectrum disorders and schizophrenia. A long gaze, on the other hand, can easily make both parties uncomfortable. All of which raises a simple question: How long is a normal gaze? To answer this question, researchers in the U.K. asked about 500 visitors to the London Science Museum to watch videos with an actor staring at them through the screen (like the one below). When the clip had ended, they asked participants to press a button to indicate whether they felt the actor had looked at them for too long or short a period of time. According to a study, the average ideal gaze time for viewers to feel comfortable was 3.3 seconds. http://www.huffingtonpost.com/entry/how-long-eye-contact-creepy_us_5783b694e4b0344d515015aa
