Pupil Dilation Gives You Away

Did you know that your eye pupils tend to dilate in stressful situations? This occurs automatically as part of the "fight-or-flight" response. The reflex is mediated by the release of the hormone noradrenalin, which in animals has also been implicated in memory and decision-making. Noradrenalin helps you to cement decisions toward which you are moving. Pupil dilation is an outward sign of this.