Even when we’re not watching each other, we’re still paying attention. It’s called ambient awareness, and it happens in real life and on social media.
When two strangers sit together, they immediately make snap observations, not necessarily about the coffee stain on the other person's shirt or one's unkempt hair but on each other's general appearance.
“Although people surreptitiously noticed all kinds of details about each other — clothing, personality, mood — we found that people were convinced that the other person wasn’t watching them much, if at all.”
We are loosely spying on each other because the brain is in constant judgment mode. Even when you think you’re not noticing, you’re noticing. We are all unintended watchers.