I'm sure my body language shows people a lot about what I'm thinking. But could the pupils of my eyes give away the answer to a decision I'm about to make?
Yes, say scientists. When they were deliberating over a tricky visual perception task, the amount people's pupils widened could predict if they'd end up choosing a positive or negative answer. I wonder if the effect is big enough to notice in real-life situations? And if so, who might want to get their hands on this technology?