Blinking as the Ultimate Stress and Focus Meter
Blink rate is one of the most reliable physiological signals available in everyday conversation. Stress drives it from the normal 15 per minute up to 85–90. Intense focus drives it down to 2. Psychopaths in interviews who don't blink aren't relaxed — they're intensely focused. Use blink rate as a real-time gauge of engagement or stress in any conversation.
