Mental and physical health issues
When you are under stress, you may become more sensitive to light and eye strain. General health conditions that may cause an increase in eye blinking include:
anxiety
stress
fatigue
[Sauce: https://www.healthline.com/health/eye-health/eye-blinking#causes]
Being under pressure
When a person is put under pressure, they might start blinking more often than usual. An interview candidate might blink excessively when asked a difficult question.
Sauce: https://www.speeli.com/what-causes-fast-and-rapid-blinking/