Can people really see what we are thinking?

"The public speaking is a crucible for what psychologists call "the illusion of transparency" – the certainty we have that our emotions, such as panic before a crowd, are written all over our faces. In truth, we're more enigmatic.But the illusion's cruel irony is that believing in it can make it true: convinced we're coming across terribly, we try to act calmer, kickstarting a vicious cycle of self-correction that does indeed end in detectible panic. If we'd known how little panic we were betraying, perhaps we'd have panicked less.

The illusion also sabotages our efforts to convey meaning. "We always know what we mean by our words," as the blogger Eliezer Yudkowsky puts it, "and so we expect others to know it, too.
"I know what I mean. How can you not?

But this needn't be depressing. First because, as the researcher Thomas Gilovich discovered, in a study highlighted at the always readable YouAreNotSoSmart.com, "the truth can set you free": merely knowing about the illusion frequently halts the vicious cycle that makes public speaking so distressing. And second because – even though it's the title of a 1970s self-help book of the cheddarish variety – there's wisdom in the observation that "what you think of me is none of my business". You can never fully grasp, much less control, how others see you. So don't waste too much energy trying."
The Guardian